move instcombine to its own library, it's past time.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92459 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 0 insertions, 14088 deletions

diff --git a/lib/Transforms/Scalar/CMakeLists.txt b/lib/Transforms/Scalar/CMakeLists.txt
index 5a92399f67..683c1c2fd7 100644
--- a/lib/Transforms/Scalar/CMakeLists.txt
+++ b/lib/Transforms/Scalar/CMakeLists.txt
@@ -9,7 +9,6 @@ add_llvm_library(LLVMScalarOpts
   GEPSplitter.cpp
   GVN.cpp
   IndVarSimplify.cpp
-  InstructionCombining.cpp
   JumpThreading.cpp
   LICM.cpp
   LoopDeletion.cpp
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
deleted file mode 100644
index 03885a5e05..0000000000
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ /dev/null
@@ -1,14087 +0,0 @@
-//===- InstructionCombining.cpp - Combine multiple instructions -----------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// InstructionCombining - Combine instructions to form fewer, simple
-// instructions.  This pass does not modify the CFG.  This pass is where
-// algebraic simplification happens.
-//
-// This pass combines things like:
-//    %Y = add i32 %X, 1
-//    %Z = add i32 %Y, 1
-// into:
-//    %Z = add i32 %X, 2
-//
-// This is a simple worklist driven algorithm.
-//
-// This pass guarantees that the following canonicalizations are performed on
-// the program:
-//    1. If a binary operator has a constant operand, it is moved to the RHS
-//    2. Bitwise operators with constant operands are always grouped so that
-//       shifts are performed first, then or's, then and's, then xor's.
-//    3. Compare instructions are converted from <,>,<=,>= to ==,!= if possible
-//    4. All cmp instructions on boolean values are replaced with logical ops
-//    5. add X, X is represented as (X*2) => (X << 1)
-//    6. Multiplies with a power-of-two constant argument are transformed into
-//       shifts.
-//   ... etc.
-//
-//===----------------------------------------------------------------------===//
-
-#define DEBUG_TYPE "instcombine"
-#include "llvm/Transforms/Scalar.h"
-#include "llvm/IntrinsicInst.h"
-#include "llvm/LLVMContext.h"
-#include "llvm/Pass.h"
-#include "llvm/DerivedTypes.h"
-#include "llvm/GlobalVariable.h"
-#include "llvm/Operator.h"
-#include "llvm/Analysis/ConstantFolding.h"
-#include "llvm/Analysis/InstructionSimplify.h"
-#include "llvm/Analysis/MemoryBuiltins.h"
-#include "llvm/Analysis/ValueTracking.h"
-#include "llvm/Target/TargetData.h"
-#include "llvm/Transforms/Utils/BasicBlockUtils.h"
-#include "llvm/Transforms/Utils/Local.h"
-#include "llvm/Support/CallSite.h"
-#include "llvm/Support/ConstantRange.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Support/ErrorHandling.h"
-#include "llvm/Support/GetElementPtrTypeIterator.h"
-#include "llvm/Support/InstVisitor.h"
-#include "llvm/Support/IRBuilder.h"
-#include "llvm/Support/MathExtras.h"
-#include "llvm/Support/PatternMatch.h"
-#include "llvm/Support/TargetFolder.h"
-#include "llvm/Support/raw_ostream.h"
-#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/SmallPtrSet.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/STLExtras.h"
-#include <algorithm>
-#include <climits>
-using namespace llvm;
-using namespace llvm::PatternMatch;
-
-STATISTIC(NumCombined , "Number of insts combined");
-STATISTIC(NumConstProp, "Number of constant folds");
-STATISTIC(NumDeadInst , "Number of dead inst eliminated");
-STATISTIC(NumDeadStore, "Number of dead stores eliminated");
-STATISTIC(NumSunkInst , "Number of instructions sunk");
-
-/// SelectPatternFlavor - We can match a variety of different patterns for
-/// select operations.
-enum SelectPatternFlavor {
-  SPF_UNKNOWN = 0,
-  SPF_SMIN, SPF_UMIN,
-  SPF_SMAX, SPF_UMAX
-  //SPF_ABS - TODO.
-};
-
-namespace {
-  /// InstCombineWorklist - This is the worklist management logic for
-  /// InstCombine.
-  class InstCombineWorklist {
-    SmallVector<Instruction*, 256> Worklist;
-    DenseMap<Instruction*, unsigned> WorklistMap;
-    
-    void operator=(const InstCombineWorklist&RHS);   // DO NOT IMPLEMENT
-    InstCombineWorklist(const InstCombineWorklist&); // DO NOT IMPLEMENT
-  public:
-    InstCombineWorklist() {}
-    
-    bool isEmpty() const { return Worklist.empty(); }
-    
-    /// Add - Add the specified instruction to the worklist if it isn't already
-    /// in it.
-    void Add(Instruction *I) {
-      if (WorklistMap.insert(std::make_pair(I, Worklist.size())).second) {
-        DEBUG(errs() << "IC: ADD: " << *I << '\n');
-        Worklist.push_back(I);
-      }
-    }
-    
-    void AddValue(Value *V) {
-      if (Instruction *I = dyn_cast<Instruction>(V))
-        Add(I);
-    }
-    
-    /// AddInitialGroup - Add the specified batch of stuff in reverse order.
-    /// which should only be done when the worklist is empty and when the group
-    /// has no duplicates.
-    void AddInitialGroup(Instruction *const *List, unsigned NumEntries) {
-      assert(Worklist.empty() && "Worklist must be empty to add initial group");
-      Worklist.reserve(NumEntries+16);
-      DEBUG(errs() << "IC: ADDING: " << NumEntries << " instrs to worklist\n");
-      for (; NumEntries; --NumEntries) {
-        Instruction *I = List[NumEntries-1];
-        WorklistMap.insert(std::make_pair(I, Worklist.size()));
-        Worklist.push_back(I);
-      }
-    }
-    
-    // Remove - remove I from the worklist if it exists.
-    void Remove(Instruction *I) {
-      DenseMap<Instruction*, unsigned>::iterator It = WorklistMap.find(I);
-      if (It == WorklistMap.end()) return; // Not in worklist.
-      
-      // Don't bother moving everything down, just null out the slot.
-      Worklist[It->second] = 0;
-      
-      WorklistMap.erase(It);
-    }
-    
-    Instruction *RemoveOne() {
-      Instruction *I = Worklist.back();
-      Worklist.pop_back();
-      WorklistMap.erase(I);
-      return I;
-    }
-
-    /// AddUsersToWorkList - When an instruction is simplified, add all users of
-    /// the instruction to the work lists because they might get more simplified
-    /// now.
-    ///
-    void AddUsersToWorkList(Instruction &I) {
-      for (Value::use_iterator UI = I.use_begin(), UE = I.use_end();
-           UI != UE; ++UI)
-        Add(cast<Instruction>(*UI));
-    }
-    
-    
-    /// Zap - check that the worklist is empty and nuke the backing store for
-    /// the map if it is large.
-    void Zap() {
-      assert(WorklistMap.empty() && "Worklist empty, but map not?");
-      
-      // Do an explicit clear, this shrinks the map if needed.
-      WorklistMap.clear();
-    }
-  };
-} // end anonymous namespace.
-
-
-namespace {
-  /// InstCombineIRInserter - This is an IRBuilder insertion helper that works
-  /// just like the normal insertion helper, but also adds any new instructions
-  /// to the instcombine worklist.
-  class InstCombineIRInserter : public IRBuilderDefaultInserter<true> {
-    InstCombineWorklist &Worklist;
-  public:
-    InstCombineIRInserter(InstCombineWorklist &WL) : Worklist(WL) {}
-    
-    void InsertHelper(Instruction *I, const Twine &Name,
-                      BasicBlock *BB, BasicBlock::iterator InsertPt) const {
-      IRBuilderDefaultInserter<true>::InsertHelper(I, Name, BB, InsertPt);
-      Worklist.Add(I);
-    }
-  };
-} // end anonymous namespace
-
-
-namespace {
-  class InstCombiner : public FunctionPass,
-                       public InstVisitor<InstCombiner, Instruction*> {
-    TargetData *TD;
-    bool MustPreserveLCSSA;
-    bool MadeIRChange;
-  public:
-    /// Worklist - All of the instructions that need to be simplified.
-    InstCombineWorklist Worklist;
-
-    /// Builder - This is an IRBuilder that automatically inserts new
-    /// instructions into the worklist when they are created.
-    typedef IRBuilder<true, TargetFolder, InstCombineIRInserter> BuilderTy;
-    BuilderTy *Builder;
-        
-    static char ID; // Pass identification, replacement for typeid
-    InstCombiner() : FunctionPass(&ID), TD(0), Builder(0) {}
-
-    LLVMContext *Context;
-    LLVMContext *getContext() const { return Context; }
-
-  public:
-    virtual bool runOnFunction(Function &F);
-    
-    bool DoOneIteration(Function &F, unsigned ItNum);
-
-    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
-      AU.addPreservedID(LCSSAID);
-      AU.setPreservesCFG();
-    }
-
-    TargetData *getTargetData() const { return TD; }
-
-    // Visitation implementation - Implement instruction combining for different
-    // instruction types.  The semantics are as follows:
-    // Return Value:
-    //    null        - No change was made
-    //     I          - Change was made, I is still valid, I may be dead though
-    //   otherwise    - Change was made, replace I with returned instruction
-    //
-    Instruction *visitAdd(BinaryOperator &I);
-    Instruction *visitFAdd(BinaryOperator &I);
-    Value *OptimizePointerDifference(Value *LHS, Value *RHS, const Type *Ty);
-    Instruction *visitSub(BinaryOperator &I);
-    Instruction *visitFSub(BinaryOperator &I);
-    Instruction *visitMul(BinaryOperator &I);
-    Instruction *visitFMul(BinaryOperator &I);
-    Instruction *visitURem(BinaryOperator &I);
-    Instruction *visitSRem(BinaryOperator &I);
-    Instruction *visitFRem(BinaryOperator &I);
-    bool SimplifyDivRemOfSelect(BinaryOperator &I);
-    Instruction *commonRemTransforms(BinaryOperator &I);
-    Instruction *commonIRemTransforms(BinaryOperator &I);
-    Instruction *commonDivTransforms(BinaryOperator &I);
-    Instruction *commonIDivTransforms(BinaryOperator &I);
-    Instruction *visitUDiv(BinaryOperator &I);
-    Instruction *visitSDiv(BinaryOperator &I);
-    Instruction *visitFDiv(BinaryOperator &I);
-    Instruction *FoldAndOfICmps(Instruction &I, ICmpInst *LHS, ICmpInst *RHS);
-    Instruction *FoldAndOfFCmps(Instruction &I, FCmpInst *LHS, FCmpInst *RHS);
-    Instruction *visitAnd(BinaryOperator &I);
-    Instruction *FoldOrOfICmps(Instruction &I, ICmpInst *LHS, ICmpInst *RHS);
-    Instruction *FoldOrOfFCmps(Instruction &I, FCmpInst *LHS, FCmpInst *RHS);
-    Instruction *FoldOrWithConstants(BinaryOperator &I, Value *Op,
-                                     Value *A, Value *B, Value *C);
-    Instruction *visitOr (BinaryOperator &I);
-    Instruction *visitXor(BinaryOperator &I);
-    Instruction *visitShl(BinaryOperator &I);
-    Instruction *visitAShr(BinaryOperator &I);
-    Instruction *visitLShr(BinaryOperator &I);
-    Instruction *commonShiftTransforms(BinaryOperator &I);
-    Instruction *FoldFCmp_IntToFP_Cst(FCmpInst &I, Instruction *LHSI,
-                                      Constant *RHSC);
-    Instruction *FoldCmpLoadFromIndexedGlobal(GetElementPtrInst *GEP,
-                                              GlobalVariable *GV, CmpInst &ICI,
-                                              ConstantInt *AndCst = 0);
-    Instruction *visitFCmpInst(FCmpInst &I);
-    Instruction *visitICmpInst(ICmpInst &I);
-    Instruction *visitICmpInstWithCastAndCast(ICmpInst &ICI);
-    Instruction *visitICmpInstWithInstAndIntCst(ICmpInst &ICI,
-                                                Instruction *LHS,
-                                                ConstantInt *RHS);
-    Instruction *FoldICmpDivCst(ICmpInst &ICI, BinaryOperator *DivI,
-                                ConstantInt *DivRHS);
-    Instruction *FoldICmpAddOpCst(ICmpInst &ICI, Value *X, ConstantInt *CI,
-                                  ICmpInst::Predicate Pred, Value *TheAdd);
-    Instruction *FoldGEPICmp(GEPOperator *GEPLHS, Value *RHS,
-                             ICmpInst::Predicate Cond, Instruction &I);
-    Instruction *FoldShiftByConstant(Value *Op0, ConstantInt *Op1,
-                                     BinaryOperator &I);
-    Instruction *commonCastTransforms(CastInst &CI);
-    Instruction *commonIntCastTransforms(CastInst &CI);
-    Instruction *commonPointerCastTransforms(CastInst &CI);
-    Instruction *visitTrunc(TruncInst &CI);
-    Instruction *visitZExt(ZExtInst &CI);
-    Instruction *visitSExt(SExtInst &CI);
-    Instruction *visitFPTrunc(FPTruncInst &CI);
-    Instruction *visitFPExt(CastInst &CI);
-    Instruction *visitFPToUI(FPToUIInst &FI);
-    Instruction *visitFPToSI(FPToSIInst &FI);
-    Instruction *visitUIToFP(CastInst &CI);
-    Instruction *visitSIToFP(CastInst &CI);
-    Instruction *visitPtrToInt(PtrToIntInst &CI);
-    Instruction *visitIntToPtr(IntToPtrInst &CI);
-    Instruction *visitBitCast(BitCastInst &CI);
-    Instruction *FoldSelectOpOp(SelectInst &SI, Instruction *TI,
-                                Instruction *FI);
-    Instruction *FoldSelectIntoOp(SelectInst &SI, Value*, Value*);
-    Instruction *FoldSPFofSPF(Instruction *Inner, SelectPatternFlavor SPF1,
-                              Value *A, Value *B, Instruction &Outer,
-                              SelectPatternFlavor SPF2, Value *C);
-    Instruction *visitSelectInst(SelectInst &SI);
-    Instruction *visitSelectInstWithICmp(SelectInst &SI, ICmpInst *ICI);
-    Instruction *visitCallInst(CallInst &CI);
-    Instruction *visitInvokeInst(InvokeInst &II);
-
-    Instruction *SliceUpIllegalIntegerPHI(PHINode &PN);
-    Instruction *visitPHINode(PHINode &PN);
-    Instruction *visitGetElementPtrInst(GetElementPtrInst &GEP);
-    Instruction *visitAllocaInst(AllocaInst &AI);
-    Instruction *visitFree(Instruction &FI);
-    Instruction *visitLoadInst(LoadInst &LI);
-    Instruction *visitStoreInst(StoreInst &SI);
-    Instruction *visitBranchInst(BranchInst &BI);
-    Instruction *visitSwitchInst(SwitchInst &SI);
-    Instruction *visitInsertElementInst(InsertElementInst &IE);
-    Instruction *visitExtractElementInst(ExtractElementInst &EI);
-    Instruction *visitShuffleVectorInst(ShuffleVectorInst &SVI);
-    Instruction *visitExtractValueInst(ExtractValueInst &EV);
-
-    // visitInstruction - Specify what to return for unhandled instructions...
-    Instruction *visitInstruction(Instruction &I) { return 0; }
-
-  private:
-    Instruction *visitCallSite(CallSite CS);
-    bool transformConstExprCastCall(CallSite CS);
-    Instruction *transformCallThroughTrampoline(CallSite CS);
-    Instruction *transformZExtICmp(ICmpInst *ICI, Instruction &CI,
-                                   bool DoXform = true);
-    bool WillNotOverflowSignedAdd(Value *LHS, Value *RHS);
-    DbgDeclareInst *hasOneUsePlusDeclare(Value *V);
-
-
-  public:
-    // InsertNewInstBefore - insert an instruction New before instruction Old
-    // in the program.  Add the new instruction to the worklist.
-    //
-    Instruction *InsertNewInstBefore(Instruction *New, Instruction &Old) {
-      assert(New && New->getParent() == 0 &&
-             "New instruction already inserted into a basic block!");
-      BasicBlock *BB = Old.getParent();
-      BB->getInstList().insert(&Old, New);  // Insert inst
-      Worklist.Add(New);
-      return New;
-    }
-        
-    // ReplaceInstUsesWith - This method is to be used when an instruction is
-    // found to be dead, replacable with another preexisting expression.  Here
-    // we add all uses of I to the worklist, replace all uses of I with the new
-    // value, then return I, so that the inst combiner will know that I was
-    // modified.
-    //
-    Instruction *ReplaceInstUsesWith(Instruction &I, Value *V) {
-      Worklist.AddUsersToWorkList(I);   // Add all modified instrs to worklist.
-      
-      // If we are replacing the instruction with itself, this must be in a
-      // segment of unreachable code, so just clobber the instruction.
-      if (&I == V) 
-        V = UndefValue::get(I.getType());
-        
-      I.replaceAllUsesWith(V);
-      return &I;
-    }
-
-    // EraseInstFromFunction - When dealing with an instruction that has side
-    // effects or produces a void value, we can't rely on DCE to delete the
-    // instruction.  Instead, visit methods should return the value returned by
-    // this function.
-    Instruction *EraseInstFromFunction(Instruction &I) {
-      DEBUG(errs() << "IC: ERASE " << I << '\n');
-
-      assert(I.use_empty() && "Cannot erase instruction that is used!");
-      // Make sure that we reprocess all operands now that we reduced their
-      // use counts.
-      if (I.getNumOperands() < 8) {
-        for (User::op_iterator i = I.op_begin(), e = I.op_end(); i != e; ++i)
-          if (Instruction *Op = dyn_cast<Instruction>(*i))
-            Worklist.Add(Op);
-      }
-      Worklist.Remove(&I);
-      I.eraseFromParent();
-      MadeIRChange = true;
-      return 0;  // Don't do anything with FI
-    }
-        
-    void ComputeMaskedBits(Value *V, const APInt &Mask, APInt &KnownZero,
-                           APInt &KnownOne, unsigned Depth = 0) const {
-      return llvm::ComputeMaskedBits(V, Mask, KnownZero, KnownOne, TD, Depth);
-    }
-    
-    bool MaskedValueIsZero(Value *V, const APInt &Mask, 
-                           unsigned Depth = 0) const {
-      return llvm::MaskedValueIsZero(V, Mask, TD, Depth);
-    }
-    unsigned ComputeNumSignBits(Value *Op, unsigned Depth = 0) const {
-      return llvm::ComputeNumSignBits(Op, TD, Depth);
-    }
-
-  private:
-
-    /// SimplifyCommutative - This performs a few simplifications for 
-    /// commutative operators.
-    bool SimplifyCommutative(BinaryOperator &I);
-
-    /// SimplifyDemandedUseBits - Attempts to replace V with a simpler value
-    /// based on the demanded bits.
-    Value *SimplifyDemandedUseBits(Value *V, APInt DemandedMask, 
-                                   APInt& KnownZero, APInt& KnownOne,
-                                   unsigned Depth);
-    bool SimplifyDemandedBits(Use &U, APInt DemandedMask, 
-                              APInt& KnownZero, APInt& KnownOne,
-                              unsigned Depth=0);
-        
-    /// SimplifyDemandedInstructionBits - Inst is an integer instruction that
-    /// SimplifyDemandedBits knows about.  See if the instruction has any
-    /// properties that allow us to simplify its operands.
-    bool SimplifyDemandedInstructionBits(Instruction &Inst);
-        
-    Value *SimplifyDemandedVectorElts(Value *V, APInt DemandedElts,
-                                      APInt& UndefElts, unsigned Depth = 0);
-      
-    // FoldOpIntoPhi - Given a binary operator, cast instruction, or select
-    // which has a PHI node as operand #0, see if we can fold the instruction
-    // into the PHI (which is only possible if all operands to the PHI are
-    // constants).
-    //
-    // If AllowAggressive is true, FoldOpIntoPhi will allow certain transforms
-    // that would normally be unprofitable because they strongly encourage jump
-    // threading.
-    Instruction *FoldOpIntoPhi(Instruction &I, bool AllowAggressive = false);
-
-    // FoldPHIArgOpIntoPHI - If all operands to a PHI node are the same "unary"
-    // operator and they all are only used by the PHI, PHI together their
-    // inputs, and do the operation once, to the result of the PHI.
-    Instruction *FoldPHIArgOpIntoPHI(PHINode &PN);
-    Instruction *FoldPHIArgBinOpIntoPHI(PHINode &PN);
-    Instruction *FoldPHIArgGEPIntoPHI(PHINode &PN);
-    Instruction *FoldPHIArgLoadIntoPHI(PHINode &PN);
-
-    
-    Instruction *OptAndOp(Instruction *Op, ConstantInt *OpRHS,
-                          ConstantInt *AndRHS, BinaryOperator &TheAnd);
-    
-    Value *FoldLogicalPlusAnd(Value *LHS, Value *RHS, ConstantInt *Mask,
-                              bool isSub, Instruction &I);
-    Instruction *InsertRangeTest(Value *V, Constant *Lo, Constant *Hi,
-                                 bool isSigned, bool Inside, Instruction &IB);
-    Instruction *PromoteCastOfAllocation(BitCastInst &CI, AllocaInst &AI);
-    Instruction *MatchBSwap(BinaryOperator &I);
-    bool SimplifyStoreAtEndOfBlock(StoreInst &SI);
-    Instruction *SimplifyMemTransfer(MemIntrinsic *MI);
-    Instruction *SimplifyMemSet(MemSetInst *MI);
-
-
-    Value *EvaluateInDifferentType(Value *V, const Type *Ty, bool isSigned);
-
-    bool CanEvaluateInDifferentType(Value *V, const Type *Ty,
-                                    unsigned CastOpc, int &NumCastsRemoved);
-    unsigned GetOrEnforceKnownAlignment(Value *V,
-                                        unsigned PrefAlign = 0);
-
-  };
-} // end anonymous namespace
-
-char InstCombiner::ID = 0;
-static RegisterPass<InstCombiner>
-X("instcombine", "Combine redundant instructions");
-
-// getComplexity:  Assign a complexity or rank value to LLVM Values...
-//   0 -> undef, 1 -> Const, 2 -> Other, 3 -> Arg, 3 -> Unary, 4 -> OtherInst
-static unsigned getComplexity(Value *V) {
-  if (isa<Instruction>(V)) {
-    if (BinaryOperator::isNeg(V) ||
-        BinaryOperator::isFNeg(V) ||
-        BinaryOperator::isNot(V))
-      return 3;
-    return 4;
-  }
-  if (isa<Argument>(V)) return 3;
-  return isa<Constant>(V) ? (isa<UndefValue>(V) ? 0 : 1) : 2;
-}
-
-// isOnlyUse - Return true if this instruction will be deleted if we stop using
-// it.
-static bool isOnlyUse(Value *V) {
-  return V->hasOneUse() || isa<Constant>(V);
-}
-
-// getPromotedType - Return the specified type promoted as it would be to pass
-// though a va_arg area...
-static const Type *getPromotedType(const Type *Ty) {
-  if (const IntegerType* ITy = dyn_cast<IntegerType>(Ty)) {
-    if (ITy->getBitWidth() < 32)
-      return Type::getInt32Ty(Ty->getContext());
-  }
-  return Ty;
-}
-
-/// ShouldChangeType - Return true if it is desirable to convert a computation
-/// from 'From' to 'To'.  We don't want to convert from a legal to an illegal
-/// type for example, or from a smaller to a larger illegal type.
-static bool ShouldChangeType(const Type *From, const Type *To,
-                             const TargetData *TD) {
-  assert(isa<IntegerType>(From) && isa<IntegerType>(To));
-  
-  // If we don't have TD, we don't know if the source/dest are legal.
-  if (!TD) return false;
-  
-  unsigned FromWidth = From->getPrimitiveSizeInBits();
-  unsigned ToWidth = To->getPrimitiveSizeInBits();
-  bool FromLegal = TD->isLegalInteger(FromWidth);
-  bool ToLegal = TD->isLegalInteger(ToWidth);
-  
-  // If this is a legal integer from type, and the result would be an illegal
-  // type, don't do the transformation.
-  if (FromLegal && !ToLegal)
-    return false;
-  
-  // Otherwise, if both are illegal, do not increase the size of the result. We
-  // do allow things like i160 -> i64, but not i64 -> i160.
-  if (!FromLegal && !ToLegal && ToWidth > FromWidth)
-    return false;
-  
-  return true;
-}
-
-/// getBitCastOperand - If the specified operand is a CastInst, a constant
-/// expression bitcast, or a GetElementPtrInst with all zero indices, return the
-/// operand value, otherwise return null.
-static Value *getBitCastOperand(Value *V) {
-  if (Operator *O = dyn_cast<Operator>(V)) {
-    if (O->getOpcode() == Instruction::BitCast)
-      return O->getOperand(0);
-    if (GEPOperator *GEP = dyn_cast<GEPOperator>(V))
-      if (GEP->hasAllZeroIndices())
-        return GEP->getPointerOperand();
-  }
-  return 0;
-}
-
-/// This function is a wrapper around CastInst::isEliminableCastPair. It
-/// simply extracts arguments and returns what that function returns.
-static Instruction::CastOps 
-isEliminableCastPair(
-  const CastInst *CI, ///< The first cast instruction
-  unsigned opcode,       ///< The opcode of the second cast instruction
-  const Type *DstTy,     ///< The target type for the second cast instruction
-  TargetData *TD         ///< The target data for pointer size
-) {
-
-  const Type *SrcTy = CI->getOperand(0)->getType();   // A from above
-  const Type *MidTy = CI->getType();                  // B from above
-
-  // Get the opcodes of the two Cast instructions
-  Instruction::CastOps firstOp = Instruction::CastOps(CI->getOpcode());
-  Instruction::CastOps secondOp = Instruction::CastOps(opcode);
-
-  unsigned Res = CastInst::isEliminableCastPair(firstOp, secondOp, SrcTy, MidTy,
-                                                DstTy,
-                                  TD ? TD->getIntPtrType(CI->getContext()) : 0);
-  
-  // We don't want to form an inttoptr or ptrtoint that converts to an integer
-  // type that differs from the pointer size.
-  if ((Res == Instruction::IntToPtr &&
-          (!TD || SrcTy != TD->getIntPtrType(CI->getContext()))) ||
-      (Res == Instruction::PtrToInt &&
-          (!TD || DstTy != TD->getIntPtrType(CI->getContext()))))
-    Res = 0;
-  
-  return Instruction::CastOps(Res);
-}
-
-/// ValueRequiresCast - Return true if the cast from "V to Ty" actually results
-/// in any code being generated.  It does not require codegen if V is simple
-/// enough or if the cast can be folded into other casts.
-static bool ValueRequiresCast(Instruction::CastOps opcode, const Value *V, 
-                              const Type *Ty, TargetData *TD) {
-  if (V->getType() == Ty || isa<Constant>(V)) return false;
-  
-  // If this is another cast that can be eliminated, it isn't codegen either.
-  if (const CastInst *CI = dyn_cast<CastInst>(V))
-    if (isEliminableCastPair(CI, opcode, Ty, TD))
-      return false;
-  return true;
-}
-
-// SimplifyCommutative - This performs a few simplifications for commutative
-// operators:
-//
-//  1. Order operands such that they are listed from right (least complex) to
-//     left (most complex).  This puts constants before unary operators before
-//     binary operators.
-//
-//  2. Transform: (op (op V, C1), C2) ==> (op V, (op C1, C2))
-//  3. Transform: (op (op V1, C1), (op V2, C2)) ==> (op (op V1, V2), (op C1,C2))
-//
-bool InstCombiner::SimplifyCommutative(BinaryOperator &I) {
-  bool Changed = false;
-  if (getComplexity(I.getOperand(0)) < getComplexity(I.getOperand(1)))
-    Changed = !I.swapOperands();
-
-  if (!I.isAssociative()) return Changed;
-  Instruction::BinaryOps Opcode = I.getOpcode();
-  if (BinaryOperator *Op = dyn_cast<BinaryOperator>(I.getOperand(0)))
-    if (Op->getOpcode() == Opcode && isa<Constant>(Op->getOperand(1))) {
-      if (isa<Constant>(I.getOperand(1))) {
-        Constant *Folded = ConstantExpr::get(I.getOpcode(),
-                                             cast<Constant>(I.getOperand(1)),
-                                             cast<Constant>(Op->getOperand(1)));
-        I.setOperand(0, Op->getOperand(0));
-        I.setOperand(1, Folded);
-        return true;
-      } else if (BinaryOperator *Op1=dyn_cast<BinaryOperator>(I.getOperand(1)))
-        if (Op1->getOpcode() == Opcode && isa<Constant>(Op1->getOperand(1)) &&
-            isOnlyUse(Op) && isOnlyUse(Op1)) {
-          Constant *C1 = cast<Constant>(Op->getOperand(1));
-          Constant *C2 = cast<Constant>(Op1->getOperand(1));
-
-          // Fold (op (op V1, C1), (op V2, C2)) ==> (op (op V1, V2), (op C1,C2))
-          Constant *Folded = ConstantExpr::get(I.getOpcode(), C1, C2);
-          Instruction *New = BinaryOperator::Create(Opcode, Op->getOperand(0),
-                                                    Op1->getOperand(0),
-                                                    Op1->getName(), &I);
-          Worklist.Add(New);
-          I.setOperand(0, New);
-          I.setOperand(1, Folded);
-          return true;
-        }
-    }
-  return Changed;
-}
-
-// dyn_castNegVal - Given a 'sub' instruction, return the RHS of the instruction
-// if the LHS is a constant zero (which is the 'negate' form).
-//
-static inline Value *dyn_castNegVal(Value *V) {
-  if (BinaryOperator::isNeg(V))
-    return BinaryOperator::getNegArgument(V);
-
-  // Constants can be considered to be negated values if they can be folded.
-  if (ConstantInt *C = dyn_cast<ConstantInt>(V))
-    return ConstantExpr::getNeg(C);
-
-  if (ConstantVector *C = dyn_cast<ConstantVector>(V))
-    if (C->getType()->getElementType()->isInteger())
-      return ConstantExpr::getNeg(C);
-
-  return 0;
-}
-
-// dyn_castFNegVal - Given a 'fsub' instruction, return the RHS of the
-// instruction if the LHS is a constant negative zero (which is the 'negate'
-// form).
-//
-static inline Value *dyn_castFNegVal(Value *V) {
-  if (BinaryOperator::isFNeg(V))
-    return BinaryOperator::getFNegArgument(V);
-
-  // Constants can be considered to be negated values if they can be folded.
-  if (ConstantFP *C = dyn_cast<ConstantFP>(V))
-    return ConstantExpr::getFNeg(C);
-
-  if (ConstantVector *C = dyn_cast<ConstantVector>(V))
-    if (C->getType()->getElementType()->isFloatingPoint())
-      return ConstantExpr::getFNeg(C);
-
-  return 0;
-}
-
-/// MatchSelectPattern - Pattern match integer [SU]MIN, [SU]MAX, and ABS idioms,
-/// returning the kind and providing the out parameter results if we
-/// successfully match.
-static SelectPatternFlavor
-MatchSelectPattern(Value *V, Value *&LHS, Value *&RHS) {
-  SelectInst *SI = dyn_cast<SelectInst>(V);
-  if (SI == 0) return SPF_UNKNOWN;
-  
-  ICmpInst *ICI = dyn_cast<ICmpInst>(SI->getCondition());
-  if (ICI == 0) return SPF_UNKNOWN;
-  
-  LHS = ICI->getOperand(0);
-  RHS = ICI->getOperand(1);
-  
-  // (icmp X, Y) ? X : Y 
-  if (SI->getTrueValue() == ICI->getOperand(0) &&
-      SI->getFalseValue() == ICI->getOperand(1)) {
-    switch (ICI->getPredicate()) {
-    default: return SPF_UNKNOWN; // Equality.
-    case ICmpInst::ICMP_UGT:
-    case ICmpInst::ICMP_UGE: return SPF_UMAX;
-    case ICmpInst::ICMP_SGT:
-    case ICmpInst::ICMP_SGE: return SPF_SMAX;
-    case ICmpInst::ICMP_ULT:
-    case ICmpInst::ICMP_ULE: return SPF_UMIN;
-    case ICmpInst::ICMP_SLT:
-    case ICmpInst::ICMP_SLE: return SPF_SMIN;
-    }
-  }
-  
-  // (icmp X, Y) ? Y : X 
-  if (SI->getTrueValue() == ICI->getOperand(1) &&
-      SI->getFalseValue() == ICI->getOperand(0)) {
-    switch (ICI->getPredicate()) {
-      default: return SPF_UNKNOWN; // Equality.
-      case ICmpInst::ICMP_UGT:
-      case ICmpInst::ICMP_UGE: return SPF_UMIN;
-      case ICmpInst::ICMP_SGT:
-      case ICmpInst::ICMP_SGE: return SPF_SMIN;
-      case ICmpInst::ICMP_ULT:
-      case ICmpInst::ICMP_ULE: return SPF_UMAX;
-      case ICmpInst::ICMP_SLT:
-      case ICmpInst::ICMP_SLE: return SPF_SMAX;
-    }
-  }
-  
-  // TODO: (X > 4) ? X : 5   -->  (X >= 5) ? X : 5  -->  MAX(X, 5)
-  
-  return SPF_UNKNOWN;
-}
-
-/// isFreeToInvert - Return true if the specified value is free to invert (apply
-/// ~ to).  This happens in cases where the ~ can be eliminated.
-static inline bool isFreeToInvert(Value *V) {
-  // ~(~(X)) -> X.
-  if (BinaryOperator::isNot(V))
-    return true;
-  
-  // Constants can be considered to be not'ed values.
-  if (isa<ConstantInt>(V))
-    return true;
-  
-  // Compares can be inverted if they have a single use.
-  if (CmpInst *CI = dyn_cast<CmpInst>(V))
-    return CI->hasOneUse();
-  
-  return false;
-}
-
-static inline Value *dyn_castNotVal(Value *V) {
-  // If this is not(not(x)) don't return that this is a not: we want the two
-  // not's to be folded first.
-  if (BinaryOperator::isNot(V)) {
-    Value *Operand = BinaryOperator::getNotArgument(V);
-    if (!isFreeToInvert(Operand))
-      return Operand;
-  }
-
-  // Constants can be considered to be not'ed values...
-  if (ConstantInt *C = dyn_cast<ConstantInt>(V))
-    return ConstantInt::get(C->getType(), ~C->getValue());
-  return 0;
-}
-
-
-
-// dyn_castFoldableMul - If this value is a multiply that can be folded into
-// other computations (because it has a constant operand), return the
-// non-constant operand of the multiply, and set CST to point to the multiplier.
-// Otherwise, return null.
-//
-static inline Value *dyn_castFoldableMul(Value *V, ConstantInt *&CST) {
-  if (V->hasOneUse() && V->getType()->isInteger())
-    if (Instruction *I = dyn_cast<Instruction>(V)) {
-      if (I->getOpcode() == Instruction::Mul)
-        if ((CST = dyn_cast<ConstantInt>(I->getOperand(1))))
-          return I->getOperand(0);
-      if (I->getOpcode() == Instruction::Shl)
-        if ((CST = dyn_cast<ConstantInt>(I->getOperand(1)))) {
-          // The multiplier is really 1 << CST.
-          uint32_t BitWidth = cast<IntegerType>(V->getType())->getBitWidth();
-          uint32_t CSTVal = CST->getLimitedValue(BitWidth);
-          CST = ConstantInt::get(V->getType()->getContext(),
-                                 APInt(BitWidth, 1).shl(CSTVal));
-          return I->getOperand(0);
-        }
-    }
-  return 0;
-}
-
-/// AddOne - Add one to a ConstantInt
-static Constant *AddOne(Constant *C) {
-  return ConstantExpr::getAdd(C, 
-    ConstantInt::get(C->getType(), 1));
-}
-/// SubOne - Subtract one from a ConstantInt
-static Constant *SubOne(ConstantInt *C) {
-  return ConstantExpr::getSub(C, 
-    ConstantInt::get(C->getType(), 1));
-}
-/// MultiplyOverflows - True if the multiply can not be expressed in an int
-/// this size.
-static bool MultiplyOverflows(ConstantInt *C1, ConstantInt *C2, bool sign) {
-  uint32_t W = C1->getBitWidth();
-  APInt LHSExt = C1->getValue(), RHSExt = C2->getValue();
-  if (sign) {
-    LHSExt.sext(W * 2);
-    RHSExt.sext(W * 2);
-  } else {
-    LHSExt.zext(W * 2);
-    RHSExt.zext(W * 2);
-  }
-
-  APInt MulExt = LHSExt * RHSExt;
-
-  if (!sign)
-    return MulExt.ugt(APInt::getLowBitsSet(W * 2, W));
-  
-  APInt Min = APInt::getSignedMinValue(W).sext(W * 2);
-  APInt Max = APInt::getSignedMaxValue(W).sext(W * 2);
-  return MulExt.slt(Min) || MulExt.sgt(Max);
-}
-
-
-/// ShrinkDemandedConstant - Check to see if the specified operand of the 
-/// specified instruction is a constant integer.  If so, check to see if there
-/// are any bits set in the constant that are not demanded.  If so, shrink the
-/// constant and return true.
-static bool ShrinkDemandedConstant(Instruction *I, unsigned OpNo, 
-                                   APInt Demanded) {
-  assert(I && "No instruction?");
-  assert(OpNo < I->getNumOperands() && "Operand index too large");
-
-  // If the operand is not a constant integer, nothing to do.
-  ConstantInt *OpC = dyn_cast<ConstantInt>(I->getOperand(OpNo));
-  if (!OpC) return false;
-
-  // If there are no bits set that aren't demanded, nothing to do.
-  Demanded.zextOrTrunc(OpC->getValue().getBitWidth());
-  if ((~Demanded & OpC->getValue()) == 0)
-    return false;
-
-  // This instruction is producing bits that are not demanded. Shrink the RHS.
-  Demanded &= OpC->getValue();
-  I->setOperand(OpNo, ConstantInt::get(OpC->getType(), Demanded));
-  return true;
-}
-
-// ComputeSignedMinMaxValuesFromKnownBits - Given a signed integer type and a 
-// set of known zero and one bits, compute the maximum and minimum values that
-// could have the specified known zero and known one bits, returning them in
-// min/max.
-static void ComputeSignedMinMaxValuesFromKnownBits(const APInt& KnownZero,
-                                                   const APInt& KnownOne,
-                                                   APInt& Min, APInt& Max) {
-  assert(KnownZero.getBitWidth() == KnownOne.getBitWidth() &&
-         KnownZero.getBitWidth() == Min.getBitWidth() &&
-         KnownZero.getBitWidth() == Max.getBitWidth() &&
-         "KnownZero, KnownOne and Min, Max must have equal bitwidth.");
-  APInt UnknownBits = ~(KnownZero|KnownOne);
-
-  // The minimum value is when all unknown bits are zeros, EXCEPT for the sign
-  // bit if it is unknown.
-  Min = KnownOne;
-  Max = KnownOne|UnknownBits;
-  
-  if (UnknownBits.isNegative()) { // Sign bit is unknown
-    Min.set(Min.getBitWidth()-1);
-    Max.clear(Max.getBitWidth()-1);
-  }
-}
-
-// ComputeUnsignedMinMaxValuesFromKnownBits - Given an unsigned integer type and
-// a set of known zero and one bits, compute the maximum and minimum values that
-// could have the specified known zero and known one bits, returning them in
-// min/max.
-static void ComputeUnsignedMinMaxValuesFromKnownBits(const APInt &KnownZero,
-                                                     const APInt &KnownOne,
-                                                     APInt &Min, APInt &Max) {
-  assert(KnownZero.getBitWidth() == KnownOne.getBitWidth() &&
-         KnownZero.getBitWidth() == Min.getBitWidth() &&
-         KnownZero.getBitWidth() == Max.getBitWidth() &&
-         "Ty, KnownZero, KnownOne and Min, Max must have equal bitwidth.");
-  APInt UnknownBits = ~(KnownZero|KnownOne);
-  
-  // The minimum value is when the unknown bits are all zeros.
-  Min = KnownOne;
-  // The maximum value is when the unknown bits are all ones.
-  Max = KnownOne|UnknownBits;
-}
-
-/// SimplifyDemandedInstructionBits - Inst is an integer instruction that
-/// SimplifyDemandedBits knows about.  See if the instruction has any
-/// properties that allow us to simplify its operands.
-bool InstCombiner::SimplifyDemandedInstructionBits(Instruction &Inst) {
-  unsigned BitWidth = Inst.getType()->getScalarSizeInBits();
-  APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
-  APInt DemandedMask(APInt::getAllOnesValue(BitWidth));
-  
-  Value *V = SimplifyDemandedUseBits(&Inst, DemandedMask, 
-                                     KnownZero, KnownOne, 0);
-  if (V == 0) return false;
-  if (V == &Inst) return true;
-  ReplaceInstUsesWith(Inst, V);
-  return true;
-}
-
-/// SimplifyDemandedBits - This form of SimplifyDemandedBits simplifies the
-/// specified instruction operand if possible, updating it in place.  It returns
-/// true if it made any change and false otherwise.
-bool InstCombiner::SimplifyDemandedBits(Use &U, APInt DemandedMask, 
-                                        APInt &KnownZero, APInt &KnownOne,
-                                        unsigned Depth) {
-  Value *NewVal = SimplifyDemandedUseBits(U.get(), DemandedMask,
-                                          KnownZero, KnownOne, Depth);
-  if (NewVal == 0) return false;
-  U = NewVal;
-  return true;
-}
-
-
-/// SimplifyDemandedUseBits - This function attempts to replace V with a simpler
-/// value based on the demanded bits.  When this function is called, it is known
-/// that only the bits set in DemandedMask of the result of V are ever used
-/// downstream. Consequently, depending on the mask and V, it may be possible
-/// to replace V with a constant or one of its operands. In such cases, this
-/// function does the replacement and returns true. In all other cases, it
-/// returns false after analyzing the expression and setting KnownOne and known
-/// to be one in the expression.  KnownZero contains all the bits that are known
-/// to be zero in the expression. These are provided to potentially allow the
-/// caller (which might recursively be SimplifyDemandedBits itself) to simplify
-/// the expression. KnownOne and KnownZero always follow the invariant that 
-/// KnownOne & KnownZero == 0. That is, a bit can't be both 1 and 0. Note that
-/// the bits in KnownOne and KnownZero may only be accurate for those bits set
-/// in DemandedMask. Note also that the bitwidth of V, DemandedMask, KnownZero
-/// and KnownOne must all be the same.
-///
-/// This returns null if it did not change anything and it permits no
-/// simplification.  This returns V itself if it did some simplification of V's
-/// operands based on the information about what bits are demanded. This returns
-/// some other non-null value if it found out that V is equal to another value
-/// in the context where the specified bits are demanded, but not for all users.
-Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
-                                             APInt &KnownZero, APInt &KnownOne,
-                                             unsigned Depth) {
-  assert(V != 0 && "Null pointer of Value???");
-  assert(Depth <= 6 && "Limit Search Depth");
-  uint32_t BitWidth = DemandedMask.getBitWidth();
-  const Type *VTy = V->getType();
-  assert((TD || !isa<PointerType>(VTy)) &&
-         "SimplifyDemandedBits needs to know bit widths!");
-  assert((!TD || TD->getTypeSizeInBits(VTy->getScalarType()) == BitWidth) &&
-         (!VTy->isIntOrIntVector() ||
-          VTy->getScalarSizeInBits() == BitWidth) &&
-         KnownZero.getBitWidth() == BitWidth &&
-         KnownOne.getBitWidth() == BitWidth &&
-         "Value *V, DemandedMask, KnownZero and KnownOne "
-         "must have same BitWidth");
-  if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
-    // We know all of the bits for a constant!
-    KnownOne = CI->getValue() & DemandedMask;
-    KnownZero = ~KnownOne & DemandedMask;
-    return 0;
-  }
-  if (isa<ConstantPointerNull>(V)) {
-    // We know all of the bits for a constant!
-    KnownOne.clear();
-    KnownZero = DemandedMask;
-    return 0;
-  }
-
-  KnownZero.clear();
-  KnownOne.clear();
-  if (DemandedMask == 0) {   // Not demanding any bits from V.
-    if (isa<UndefValue>(V))
-      return 0;
-    return UndefValue::get(VTy);
-  }
-  
-  if (Depth == 6)        // Limit search depth.
-    return 0;
-  
-  APInt LHSKnownZero(BitWidth, 0), LHSKnownOne(BitWidth, 0);
-  APInt &RHSKnownZero = KnownZero, &RHSKnownOne = KnownOne;
-
-  Instruction *I = dyn_cast<Instruction>(V);
-  if (!I) {
-    ComputeMaskedBits(V, DemandedMask, RHSKnownZero, RHSKnownOne, Depth);
-    return 0;        // Only analyze instructions.
-  }
-
-  // If there are multiple uses of this value and we aren't at the root, then
-  // we can't do any simplifications of the operands, because DemandedMask
-  // only reflects the bits demanded by *one* of the users.
-  if (Depth != 0 && !I->hasOneUse()) {
-    // Despite the fact that we can't simplify this instruction in all User's
-    // context, we can at least compute the knownzero/knownone bits, and we can
-    // do simplifications that apply to *just* the one user if we know that
-    // this instruction has a simpler value in that context.
-    if (I->getOpcode() == Instruction::And) {
-      // If either the LHS or the RHS are Zero, the result is zero.
-      ComputeMaskedBits(I->getOperand(1), DemandedMask,
-                        RHSKnownZero, RHSKnownOne, Depth+1);
-      ComputeMaskedBits(I->getOperand(0), DemandedMask & ~RHSKnownZero,
-                        LHSKnownZero, LHSKnownOne, Depth+1);
-      
-      // If all of the demanded bits are known 1 on one side, return the other.
-      // These bits cannot contribute to the result of the 'and' in this
-      // context.
-      if ((DemandedMask & ~LHSKnownZero & RHSKnownOne) == 
-          (DemandedMask & ~LHSKnownZero))
-        return I->getOperand(0);
-      if ((DemandedMask & ~RHSKnownZero & LHSKnownOne) == 
-          (DemandedMask & ~RHSKnownZero))
-        return I->getOperand(1);
-      
-      // If all of the demanded bits in the inputs are known zeros, return zero.
-      if ((DemandedMask & (RHSKnownZero|LHSKnownZero)) == DemandedMask)
-        return Constant::getNullValue(VTy);
-      
-    } else if (I->getOpcode() == Instruction::Or) {
-      // We can simplify (X|Y) -> X or Y in the user's context if we know that
-      // only bits from X or Y are demanded.
-      
-      // If either the LHS or the RHS are One, the result is One.
-      ComputeMaskedBits(I->getOperand(1), DemandedMask, 
-                        RHSKnownZero, RHSKnownOne, Depth+1);
-      ComputeMaskedBits(I->getOperand(0), DemandedMask & ~RHSKnownOne, 
-                        LHSKnownZero, LHSKnownOne, Depth+1);
-      
-      // If all of the demanded bits are known zero on one side, return the
-      // other.  These bits cannot contribute to the result of the 'or' in this
-      // context.
-      if ((DemandedMask & ~LHSKnownOne & RHSKnownZero) == 
-          (DemandedMask & ~LHSKnownOne))
-        return I->getOperand(0);
-      if ((DemandedMask & ~RHSKnownOne & LHSKnownZero) == 
-          (DemandedMask & ~RHSKnownOne))
-        return I->getOperand(1);
-      
-      // If all of the potentially set bits on one side are known to be set on
-      // the other side, just use the 'other' side.
-      if ((DemandedMask & (~RHSKnownZero) & LHSKnownOne) == 
-          (DemandedMask & (~RHSKnownZero)))
-        return I->getOperand(0);
-      if ((DemandedMask & (~LHSKnownZero) & RHSKnownOne) == 
-          (DemandedMask & (~LHSKnownZero)))
-        return I->getOperand(1);
-    }
-    
-    // Compute the KnownZero/KnownOne bits to simplify things downstream.
-    ComputeMaskedBits(I, DemandedMask, KnownZero, KnownOne, Depth);
-    return 0;
-  }
-  
-  // If this is the root being simplified, allow it to have multiple uses,
-  // just set the DemandedMask to all bits so that we can try to simplify the
-  // operands.  This allows visitTruncInst (for example) to simplify the
-  // operand of a trunc without duplicating all the logic below.
-  if (Depth == 0 && !V->hasOneUse())
-    DemandedMask = APInt::getAllOnesValue(BitWidth);
-  
-  switch (I->getOpcode()) {
-  default:
-    ComputeMaskedBits(I, DemandedMask, RHSKnownZero, RHSKnownOne, Depth);
-    break;
-  case Instruction::And:
-    // If either the LHS or the RHS are Zero, the result is zero.
-    if (SimplifyDemandedBits(I->getOperandUse(1), DemandedMask,
-                             RHSKnownZero, RHSKnownOne, Depth+1) ||
-        SimplifyDemandedBits(I->getOperandUse(0), DemandedMask & ~RHSKnownZero,
-                             LHSKnownZero, LHSKnownOne, Depth+1))
-      return I;
-    assert(!(RHSKnownZero & RHSKnownOne) && "Bits known to be one AND zero?"); 
-    assert(!(LHSKnownZero & LHSKnownOne) && "Bits known to be one AND zero?"); 
-
-    // If all of the demanded bits are known 1 on one side, return the other.
-    // These bits cannot contribute to the result of the 'and'.
-    if ((DemandedMask & ~LHSKnownZero & RHSKnownOne) == 
-        (DemandedMask & ~LHSKnownZero))
-      return I->getOperand(0);
-    if ((DemandedMask & ~RHSKnownZero & LHSKnownOne) == 
-        (DemandedMask & ~RHSKnownZero))
-      return I->getOperand(1);
-    
-    // If all of the demanded bits in the inputs are known zeros, return zero.
-    if ((DemandedMask & (RHSKnownZero|LHSKnownZero)) == DemandedMask)
-      return Constant::getNullValue(VTy);
-      
-    // If the RHS is a constant, see if we can simplify it.
-    if (ShrinkDemandedConstant(I, 1, DemandedMask & ~LHSKnownZero))
-      return I;
-      
-    // Output known-1 bits are only known if set in both the LHS & RHS.
-    RHSKnownOne &= LHSKnownOne;
-    // Output known-0 are known to be clear if zero in either the LHS | RHS.
-    RHSKnownZero |= LHSKnownZero;
-    break;
-  case Instruction::Or:
-    // If either the LHS or the RHS are One, the result is One.
-    if (SimplifyDemandedBits(I->getOperandUse(1), DemandedMask, 
-                             RHSKnownZero, RHSKnownOne, Depth+1) ||
-        SimplifyDemandedBits(I->getOperandUse(0), DemandedMask & ~RHSKnownOne, 
-                             LHSKnownZero, LHSKnownOne, Depth+1))
-      return I;
-    assert(!(RHSKnownZero & RHSKnownOne) && "Bits known to be one AND zero?"); 
-    assert(!(LHSKnownZero & LHSKnownOne) && "Bits known to be one AND zero?"); 
-    
-    // If all of the demanded bits are known zero on one side, return the other.
-    // These bits cannot contribute to the result of the 'or'.
-    if ((DemandedMask & ~LHSKnownOne & RHSKnownZero) == 
-        (DemandedMask & ~LHSKnownOne))
-      return I->getOperand(0);
-    if ((DemandedMask & ~RHSKnownOne & LHSKnownZero) == 
-        (DemandedMask & ~RHSKnownOne))
-      return I->getOperand(1);
-
-    // If all of the potentially set bits on one side are known to be set on
-    // the other side, just use the 'other' side.
-    if ((DemandedMask & (~RHSKnownZero) & LHSKnownOne) == 
-        (DemandedMask & (~RHSKnownZero)))
-      return I->getOperand(0);
-    if ((DemandedMask & (~LHSKnownZero) & RHSKnownOne) == 
-        (DemandedMask & (~LHSKnownZero)))
-      return I->getOperand(1);
-        
-    // If the RHS is a constant, see if we can simplify it.
-    if (ShrinkDemandedConstant(I, 1, DemandedMask))
-      return I;
-          
-    // Output known-0 bits are only known if clear in both the LHS & RHS.
-    RHSKnownZero &= LHSKnownZero;
-    // Output known-1 are known to be set if set in either the LHS | RHS.
-    RHSKnownOne |= LHSKnownOne;
-    break;
-  case Instruction::Xor: {
-    if (SimplifyDemandedBits(I->getOperandUse(1), DemandedMask,
-                             RHSKnownZero, RHSKnownOne, Depth+1) ||
-        SimplifyDemandedBits(I->getOperandUse(0), DemandedMask, 
-                             LHSKnownZero, LHSKnownOne, Depth+1))
-      return I;
-    assert(!(RHSKnownZero & RHSKnownOne) && "Bits known to be one AND zero?"); 
-    assert(!(LHSKnownZero & LHSKnownOne) && "Bits known to be one AND zero?"); 
-    
-    // If all of the demanded bits are known zero on one side, return the other.
-    // These bits cannot contribute to the result of the 'xor'.
-    if ((DemandedMask & RHSKnownZero) == DemandedMask)
-      return I->getOperand(0);
-    if ((DemandedMask & LHSKnownZero) == DemandedMask)
-      return I->getOperand(1);
-    
-    // Output known-0 bits are known if clear or set in both the LHS & RHS.
-    APInt KnownZeroOut = (RHSKnownZero & LHSKnownZero) | 
-                         (RHSKnownOne & LHSKnownOne);
-    // Output known-1 are known to be set if set in only one of the LHS, RHS.
-    APInt KnownOneOut = (RHSKnownZero & LHSKnownOne) | 
-                        (RHSKnownOne & LHSKnownZero);
-    
-    // If all of the demanded bits are known to be zero on one side or the
-    // other, turn this into an *inclusive* or.
-    //    e.g. (A & C1)^(B & C2) -> (A & C1)|(B & C2) iff C1&C2 == 0
-    if ((DemandedMask & ~RHSKnownZero & ~LHSKnownZero) == 0) {
-      Instruction *Or = 
-        BinaryOperator::CreateOr(I->getOperand(0), I->getOperand(1),
-                                 I->getName());
-      return InsertNewInstBefore(Or, *I);
-    }
-    
-    // If all of the demanded bits on one side are known, and all of the set
-    // bits on that side are also known to be set on the other side, turn this
-    // into an AND, as we know the bits will be cleared.
-    //    e.g. (X | C1) ^ C2 --> (X | C1) & ~C2 iff (C1&C2) == C2
-    if ((DemandedMask & (RHSKnownZero|RHSKnownOne)) == DemandedMask) { 
-      // all known
-      if ((RHSKnownOne & LHSKnownOne) == RHSKnownOne) {
-        Constant *AndC = Constant::getIntegerValue(VTy,
-                                                   ~RHSKnownOne & DemandedMask);
-        Instruction *And = 
-          BinaryOperator::CreateAnd(I->getOperand(0), AndC, "tmp");
-        return InsertNewInstBefore(And, *I);
-      }
-    }
-    
-    // If the RHS is a constant, see if we can simplify it.
-    // FIXME: for XOR, we prefer to force bits to 1 if they will make a -1.
-    if (ShrinkDemandedConstant(I, 1, DemandedMask))
-      return I;
-    
-    // If our LHS is an 'and' and if it has one use, and if any of the bits we
-    // are flipping are known to be set, then the xor is just resetting those
-    // bits to zero.  We can just knock out bits from the 'and' and the 'xor',
-    // simplifying both of them.
-    if (Instruction *LHSInst = dyn_cast<Instruction>(I->getOperand(0)))
-      if (LHSInst->getOpcode() == Instruction::And && LHSInst->hasOneUse() &&
-          isa<ConstantInt>(I->getOperand(1)) &&
-          isa<ConstantInt>(LHSInst->getOperand(1)) &&
-          (LHSKnownOne & RHSKnownOne & DemandedMask) != 0) {
-        ConstantInt *AndRHS = cast<ConstantInt>(LHSInst->getOperand(1));
-        ConstantInt *XorRHS = cast<ConstantInt>(I->getOperand(1));
-        APInt NewMask = ~(LHSKnownOne & RHSKnownOne & DemandedMask);
-        
-        Constant *AndC =
-          ConstantInt::get(I->getType(), NewMask & AndRHS->getValue());
-        Instruction *NewAnd = 
-          BinaryOperator::CreateAnd(I->getOperand(0), AndC, "tmp");
-        InsertNewInstBefore(NewAnd, *I);
-        
-        Constant *XorC =
-          ConstantInt::get(I->getType(), NewMask & XorRHS->getValue());
-        Instruction *NewXor =
-          BinaryOperator::CreateXor(NewAnd, XorC, "tmp");
-        return InsertNewInstBefore(NewXor, *I);
-      }
-          
-          
-    RHSKnownZero = KnownZeroOut;
-    RHSKnownOne  = KnownOneOut;
-    break;
-  }
-  case Instruction::Select:
-    if (SimplifyDemandedBits(I->getOperandUse(2), DemandedMask,
-                             RHSKnownZero, RHSKnownOne, Depth+1) ||
-        SimplifyDemandedBits(I->getOperandUse(1), DemandedMask, 
-                             LHSKnownZero, LHSKnownOne, Depth+1))
-      return I;
-    assert(!(RHSKnownZero & RHSKnownOne) && "Bits known to be one AND zero?"); 
-    assert(!(LHSKnownZero & LHSKnownOne) && "Bits known to be one AND zero?"); 
-    
-    // If the operands are constants, see if we can simplify them.
-    if (ShrinkDemandedConstant(I, 1, DemandedMask) ||
-        ShrinkDemandedConstant(I, 2, DemandedMask))
-      return I;
-    
-    // Only known if known in both the LHS and RHS.
-    RHSKnownOne &= LHSKnownOne;
-    RHSKnownZero &= LHSKnownZero;
-    break;
-  case Instruction::Trunc: {
-    unsigned truncBf = I->getOperand(0)->getType()->getScalarSizeInBits();
-    DemandedMask.zext(truncBf);
-    RHSKnownZero.zext(truncBf);
-    RHSKnownOne.zext(truncBf);
-    if (SimplifyDemandedBits(I->getOperandUse(0), DemandedMask, 
-                             RHSKnownZero, RHSKnownOne, Depth+1))
-      return I;
-    DemandedMask.trunc(BitWidth);
-    RHSKnownZero.trunc(BitWidth);
-    RHSKnownOne.trunc(BitWidth);
-    assert(!(RHSKnownZero & RHSKnownOne) && "Bits known to be one AND zero?"); 
-    break;
-  }
-  case Instruction::BitCast:
-    if (!I->getOperand(0)->getType()->isIntOrIntVector())
-      return false;  // vector->int or fp->int?
-
-    if (const VectorType *DstVTy = dyn_cast<VectorType>(I->getType())) {
-      if (const VectorType *SrcVTy =
-            dyn_cast<VectorType>(I->getOperand(0)->getType())) {
-        if (DstVTy->getNumElements() != SrcVTy->getNumElements())
-          // Don't touch a bitcast between vectors of different element counts.
-          return false;
-      } else
-        // Don't touch a scalar-to-vector bitcast.
-        return false;
-    } else if (isa<VectorType>(I->getOperand(0)->getType()))
-      // Don't touch a vector-to-scalar bitcast.
-      return false;
-
-    if (SimplifyDemandedBits(I->getOperandUse(0), DemandedMask,
-                             RHSKnownZero, RHSKnownOne, Depth+1))
-      return I;
-    assert(!(RHSKnownZero & RHSKnownOne) && "Bits known to be one AND zero?"); 
-    break;
-  case Instruction::ZExt: {
-    // Compute the bits in the result that are not present in the input.
-    unsigned SrcBitWidth =I->getOperand(0)->getType()->getScalarSizeInBits();
-    
-    DemandedMask.trunc(SrcBitWidth);
-    RHSKnownZero.trunc(SrcBitWidth);
-    RHSKnownOne.trunc(SrcBitWidth);
-    if (SimplifyDemandedBits(I->getOperandUse(0), DemandedMask,
-                             RHSKnownZero, RHSKnownOne, Depth+1))
-      return I;
-    DemandedMask.zext(BitWidth);
-    RHSKnownZero.zext(BitWidth);
-    RHSKnownOne.zext(BitWidth);
-    assert(!(RHSKnownZero & RHSKnownOne) && "Bits known to be one AND zero?"); 
-    // The top bits are known to be zero.
-    RHSKnownZero |= APInt::getHighBitsSet(BitWidth, BitWidth - SrcBitWidth);
-    break;
-  }
-  case Instruction::SExt: {
-    // Compute the bits in the result that are not present in the input.
-    unsigned SrcBitWidth =I->getOperand(0)->getType()->getScalarSizeInBits();
-    
-    APInt InputDemandedBits = DemandedMask & 
-                              APInt::getLowBitsSet(BitWidth, SrcBitWidth);
-
-    APInt NewBits(APInt::getHighBitsSet(BitWidth, BitWidth - SrcBitWidth));
-    // If any of the sign extended bits are demanded, we know that the sign
-    // bit is demanded.
-    if ((NewBits & DemandedMask) != 0)
-      InputDemandedBits.set(SrcBitWidth-1);
-      
-    InputDemandedBits.trunc(SrcBitWidth);
-    RHSKnownZero.trunc(SrcBitWidth);
-    RHSKnownOne.trunc(SrcBitWidth);
-    if (SimplifyDemandedBits(I->getOperandUse(0), InputDemandedBits,
-                             RHSKnownZero, RHSKnownOne, Depth+1))
-      return I;
-    InputDemandedBits.zext(BitWidth);
-    RHSKnownZero.zext(BitWidth);
-    RHSKnownOne.zext(BitWidth);
-    assert(!(RHSKnownZero & RHSKnownOne) && "Bits known to be one AND zero?"); 
-      
-    // If the sign bit of the input is known set or clear, then we know the
-    // top bits of the result.
-
-    // If the input sign bit is known zero, or if the NewBits are not demanded
-    // convert this into a zero extension.
-    if (RHSKnownZero[SrcBitWidth-1] || (NewBits & ~DemandedMask) == NewBits) {
-      // Convert to ZExt cast
-      CastInst *NewCast = new ZExtInst(I->getOperand(0), VTy, I->getName());
-      return InsertNewInstBefore(NewCast, *I);
-    } else if (RHSKnownOne[SrcBitWidth-1]) {    // Input sign bit known set
-      RHSKnownOne |= NewBits;
-    }
-    break;
-  }
-  case Instruction::Add: {
-    // Figure out what the input bits are.  If the top bits of the and result
-    // are not demanded, then the add doesn't demand them from its input
-    // either.
-    unsigned NLZ = DemandedMask.countLeadingZeros();
-      
-    // If there is a constant on the RHS, there are a variety of xformations
-    // we can do.
-    if (ConstantInt *RHS = dyn_cast<ConstantInt>(I->getOperand(1))) {
-      // If null, this should be simplified elsewhere.  Some of the xforms here
-      // won't work if the RHS is zero.
-      if (RHS->isZero())
-        break;
-      
-      // If the top bit of the output is demanded, demand everything from the
-      // input.  Otherwise, we demand all the input bits except NLZ top bits.
-      APInt InDemandedBits(APInt::getLowBitsSet(BitWidth, BitWidth - NLZ));
-
-      // Find information about known zero/one bits in the input.
-      if (SimplifyDemandedBits(I->getOperandUse(0), InDemandedBits, 
-                               LHSKnownZero, LHSKnownOne, Depth+1))
-        return I;
-
-      // If the RHS of the add has bits set that can't affect the input, reduce
-      // the constant.
-      if (ShrinkDemandedConstant(I, 1, InDemandedBits))
-        return I;
-      
-      // Avoid excess work.
-      if (LHSKnownZero == 0 && LHSKnownOne == 0)
-        break;
-      
-      // Turn it into OR if input bits are zero.
-      if ((LHSKnownZero & RHS->getValue()) == RHS->getValue()) {
-        Instruction *Or =
-          BinaryOperator::CreateOr(I->getOperand(0), I->getOperand(1),
-                                   I->getName());
-        return InsertNewInstBefore(Or, *I);
-      }
-      
-      // We can say something about the output known-zero and known-one bits,
-      // depending on potential carries from the input constant and the
-      // unknowns.  For example if the LHS is known to have at most the 0x0F0F0
-      // bits set and the RHS constant is 0x01001, then we know we have a known
-      // one mask of 0x00001 and a known zero mask of 0xE0F0E.
-      
-      // To compute this, we first compute the potential carry bits.  These are
-      // the bits which may be modified.  I'm not aware of a better way to do
-      // this scan.
-      const APInt &RHSVal = RHS->getValue();
-      APInt CarryBits((~LHSKnownZero + RHSVal) ^ (~LHSKnownZero ^ RHSVal));
-      
-      // Now that we know which bits have carries, compute the known-1/0 sets.
-      
-      // Bits are known one if they are known zero in one operand and one in the
-      // other, and there is no input carry.
-      RHSKnownOne = ((LHSKnownZero & RHSVal) | 
-                     (LHSKnownOne & ~RHSVal)) & ~CarryBits;
-      
-      // Bits are known zero if they are known zero in both operands and there
-      // is no input carry.
-      RHSKnownZero = LHSKnownZero & ~RHSVal & ~CarryBits;
-    } else {
-      // If the high-bits of this ADD are not demanded, then it does not demand
-      // the high bits of its LHS or RHS.
-      if (DemandedMask[BitWidth-1] == 0) {
-        // Right fill the mask of bits for this ADD to demand the most
-        // significant bit and all those below it.
-        APInt DemandedFromOps(APInt::getLowBitsSet(BitWidth, BitWidth-NLZ));
-        if (SimplifyDemandedBits(I->getOperandUse(0), DemandedFromOps,
-                                 LHSKnownZero, LHSKnownOne, Depth+1) ||
-            SimplifyDemandedBits(I->getOperandUse(1), DemandedFromOps,
-                                 LHSKnownZero, LHSKnownOne, Depth+1))
-          return I;
-      }
-    }
-    break;
-  }
-  case Instruction::Sub:
-    // If the high-bits of this SUB are not demanded, then it does not demand
-    // the high bits of its LHS or RHS.
-    if (DemandedMask[BitWidth-1] == 0) {
-      // Right fill the mask of bits for this SUB to demand the most
-      // significant bit and all those below it.
-      uint32_t NLZ = DemandedMask.countLeadingZeros();
-      APInt DemandedFromOps(APInt::getLowBitsSet(BitWidth, BitWidth-NLZ));
-      if (SimplifyDemandedBits(I->getOperandUse(0), DemandedFromOps,
-                               LHSKnownZero, LHSKnownOne, Depth+1) ||
-          SimplifyDemandedBits(I->getOperandUse(1), DemandedFromOps,
-                               LHSKnownZero, LHSKnownOne, Depth+1))
-        return I;
-    }
-    // Otherwise just hand the sub off to ComputeMaskedBits to fill in
-    // the known zeros and ones.
-    ComputeMaskedBits(V, DemandedMask, RHSKnownZero, RHSKnownOne, Depth);
-    break;
-  case Instruction::Shl:
-    if (ConstantInt *SA = dyn_cast<ConstantInt>(I->getOperand(1))) {
-      uint64_t ShiftAmt = SA->getLimitedValue(BitWidth);
-      APInt DemandedMaskIn(DemandedMask.lshr(ShiftAmt));
-      if (SimplifyDemandedBits(I->getOperandUse(0), DemandedMaskIn, 
-                               RHSKnownZero, RHSKnownOne, Depth+1))
-        return I;
-      assert(!(RHSKnownZero & RHSKnownOne) && "Bits known to be one AND zero?");
-      RHSKnownZero <<= ShiftAmt;
-      RHSKnownOne  <<= ShiftAmt;
-      // low bits known zero.
-      if (ShiftAmt)
-        RHSKnownZero |= APInt::getLowBitsSet(BitWidth, ShiftAmt);
-    }
-    break;
-  case Instruction::LShr:
-    // For a logical shift right
-    if (ConstantInt *SA = dyn_cast<ConstantInt>(I->getOperand(1))) {
-      uint64_t ShiftAmt = SA->getLimitedValue(BitWidth);
-      
-      // Unsigned shift right.
-      APInt DemandedMaskIn(DemandedMask.shl(ShiftAmt));
-      if (SimplifyDemandedBits(I->getOperandUse(0), DemandedMaskIn,
-                               RHSKnownZero, RHSKnownOne, Depth+1))
-        return I;
-      assert(!(RHSKnownZero & RHSKnownOne) && "Bits known to be one AND zero?");
-      RHSKnownZero = APIntOps::lshr(RHSKnownZero, ShiftAmt);
-      RHSKnownOne  = APIntOps::lshr(RHSKnownOne, ShiftAmt);
-      if (ShiftAmt) {
-        // Compute the new bits that are at the top now.
-        APInt HighBits(APInt::getHighBitsSet(BitWidth, ShiftAmt));
-        RHSKnownZero |= HighBits;  // high bits known zero.
-      }
-    }
-    break;
-  case Instruction::AShr:
-    // If this is an arithmetic shift right and only the low-bit is set, we can
-    // always convert this into a logical shr, even if the shift amount is
-    // variable.  The low bit of the shift cannot be an input sign bit unless
-    // the shift amount is >= the size of the datatype, which is undefined.
-    if (DemandedMask == 1) {
-      // Perform the logical shift right.
-      Instruction *NewVal = BinaryOperator::CreateLShr(
-                        I->getOperand(0), I->getOperand(1), I->getName());
-      return InsertNewInstBefore(NewVal, *I);
-    }    
-
-    // If the sign bit is the only bit demanded by this ashr, then there is no
-    // need to do it, the shift doesn't change the high bit.
-    if (DemandedMask.isSignBit())
-      return I->getOperand(0);
-    
-    if (ConstantInt *SA = dyn_cast<ConstantInt>(I->getOperand(1))) {
-      uint32_t ShiftAmt = SA->getLimitedValue(BitWidth);
-      
-      // Signed shift right.
-      APInt DemandedMaskIn(DemandedMask.shl(ShiftAmt));
-      // If any of the "high bits" are demanded, we should set the sign bit as
-      // demanded.
-      if (DemandedMask.countLeadingZeros() <= ShiftAmt)
-        DemandedMaskIn.set(BitWidth-1);
-      if (SimplifyDemandedBits(I->getOperandUse(0), DemandedMaskIn,
-                               RHSKnownZero, RHSKnownOne, Depth+1))
-        return I;
-      assert(!(RHSKnownZero & RHSKnownOne) && "Bits known to be one AND zero?");
-      // Compute the new bits that are at the top now.
-      APInt HighBits(APInt::getHighBitsSet(BitWidth, ShiftAmt));
-      RHSKnownZero = APIntOps::lshr(RHSKnownZero, ShiftAmt);
-      RHSKnownOne  = APIntOps::lshr(RHSKnownOne, ShiftAmt);
-        
-      // Handle the sign bits.
-      APInt SignBit(APInt::getSignBit(BitWidth));
-      // Adjust to where it is now in the mask.
-      SignBit = APIntOps::lshr(SignBit, ShiftAmt);  
-        
-      // If the input sign bit is known to be zero, or if none of the top bits
-      // are demanded, turn this into an unsigned shift right.
-      if (BitWidth <= ShiftAmt || RHSKnownZero[BitWidth-ShiftAmt-1] || 
-          (HighBits & ~DemandedMask) == HighBits) {
-        // Perform the logical shift right.
-        Instruction *NewVal = BinaryOperator::CreateLShr(
-                          I->getOperand(0), SA, I->getName());
-        return InsertNewInstBefore(NewVal, *I);
-      } else if ((RHSKnownOne & SignBit) != 0) { // New bits are known one.
-        RHSKnownOne |= HighBits;
-      }
-    }
-    break;
-  case Instruction::SRem:
-    if (ConstantInt *Rem = dyn_cast<ConstantInt>(I->getOperand(1))) {
-      APInt RA = Rem->getValue().abs();
-      if (RA.isPowerOf2()) {
-        if (DemandedMask.ult(RA))    // srem won't affect demanded bits
-          return I->getOperand(0);
-
-        APInt LowBits = RA - 1;
-        APInt Mask2 = LowBits | APInt::getSignBit(BitWidth);
-        if (SimplifyDemandedBits(I->getOperandUse(0), Mask2,
-                                 LHSKnownZero, LHSKnownOne, Depth+1))
-          return I;
-
-        if (LHSKnownZero[BitWidth-1] || ((LHSKnownZero & LowBits) == LowBits))
-          LHSKnownZero |= ~LowBits;
-
-        KnownZero |= LHSKnownZero & DemandedMask;
-
-        assert(!(KnownZero & KnownOne) && "Bits known to be one AND zero?"); 
-      }
-    }
-    break;
-  case Instruction::URem: {
-    APInt KnownZero2(BitWidth, 0), KnownOne2(BitWidth, 0);
-    APInt AllOnes = APInt::getAllOnesValue(BitWidth);
-    if (SimplifyDemandedBits(I->getOperandUse(0), AllOnes,
-                             KnownZero2, KnownOne2, Depth+1) ||
-        SimplifyDemandedBits(I->getOperandUse(1), AllOnes,
-                             KnownZero2, KnownOne2, Depth+1))
-      return I;
-
-    unsigned Leaders = KnownZero2.countLeadingOnes();
-    Leaders = std::max(Leaders,
-                       KnownZero2.countLeadingOnes());
-    KnownZero = APInt::getHighBitsSet(BitWidth, Leaders) & DemandedMask;
-    break;
-  }
-  case Instruction::Call:
-    if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
-      switch (II->getIntrinsicID()) {
-      default: break;
-      case Intrinsic::bswap: {
-        // If the only bits demanded come from one byte of the bswap result,
-        // just shift the input byte into position to eliminate the bswap.
-        unsigned NLZ = DemandedMask.countLeadingZeros();
-        unsigned NTZ = DemandedMask.countTrailingZeros();
-          
-        // Round NTZ down to the next byte.  If we have 11 trailing zeros, then
-        // we need all the bits down to bit 8.  Likewise, round NLZ.  If we
-        // have 14 leading zeros, round to 8.
-        NLZ &= ~7;
-        NTZ &= ~7;
-        // If we need exactly one byte, we can do this transformation.
-        if (BitWidth-NLZ-NTZ == 8) {
-          unsigned ResultBit = NTZ;
-          unsigned InputBit = BitWidth-NTZ-8;
-          
-          // Replace this with either a left or right shift to get the byte into
-          // the right place.
-          Instruction *NewVal;
-          if (InputBit > ResultBit)
-            NewVal = BinaryOperator::CreateLShr(I->getOperand(1),
-                    ConstantInt::get(I->getType(), InputBit-ResultBit));
-          else
-            NewVal = BinaryOperator::CreateShl(I->getOperand(1),
-                    ConstantInt::get(I->getType(), ResultBit-InputBit));
-          NewVal->takeName(I);
-          return InsertNewInstBefore(NewVal, *I);
-        }
-          
-        // TODO: Could compute known zero/one bits based on the input.
-        break;
-      }
-      }
-    }
-    ComputeMaskedBits(V, DemandedMask, RHSKnownZero, RHSKnownOne, Depth);
-    break;
-  }
-  
-  // If the client is only demanding bits that we know, return the known
-  // constant.
-  if ((DemandedMask & (RHSKnownZero|RHSKnownOne)) == DemandedMask)
-    return Constant::getIntegerValue(VTy, RHSKnownOne);
-  return false;
-}
-
-
-/// SimplifyDemandedVectorElts - The specified value produces a vector with
-/// any number of elements. DemandedElts contains the set of elements that are
-/// actually used by the caller.  This method analyzes which elements of the
-/// operand are undef and returns that information in UndefElts.
-///
-/// If the information about demanded elements can be used to simplify the
-/// operation, the operation is simplified, then the resultant value is
-/// returned.  This returns null if no change was made.
-Value *InstCombiner::SimplifyDemandedVectorElts(Value *V, APInt DemandedElts,
-                                                APInt& UndefElts,
-                                                unsigned Depth) {
-  unsigned VWidth = cast<VectorType>(V->getType())->getNumElements();
-  APInt EltMask(APInt::getAllOnesValue(VWidth));
-  assert((DemandedElts & ~EltMask) == 0 && "Invalid DemandedElts!");
-
-  if (isa<UndefValue>(V)) {
-    // If the entire vector is undefined, just return this info.
-    UndefElts = EltMask;
-    return 0;
-  } else if (DemandedElts == 0) { // If nothing is demanded, provide undef.
-    UndefElts = EltMask;
-    return UndefValue::get(V->getType());
-  }
-
-  UndefElts = 0;
-  if (ConstantVector *CP = dyn_cast<ConstantVector>(V)) {
-    const Type *EltTy = cast<VectorType>(V->getType())->getElementType();
-    Constant *Undef = UndefValue::get(EltTy);
-
-    std::vector<Constant*> Elts;
-    for (unsigned i = 0; i != VWidth; ++i)
-      if (!DemandedElts[i]) {   // If not demanded, set to undef.
-        Elts.push_back(Undef);
-        UndefElts.set(i);
-      } else if (isa<UndefValue>(CP->getOperand(i))) {   // Already undef.
-        Elts.push_back(Undef);
-        UndefElts.set(i);
-      } else {                               // Otherwise, defined.
-        Elts.push_back(CP->getOperand(i));
-      }
-
-    // If we changed the constant, return it.
-    Constant *NewCP = ConstantVector::get(Elts);
-    return NewCP != CP ? NewCP : 0;
-  } else if (isa<ConstantAggregateZero>(V)) {
-    // Simplify the CAZ to a ConstantVector where the non-demanded elements are
-    // set to undef.
-    
-    // Check if this is identity. If so, return 0 since we are not simplifying
-    // anything.
-    if (DemandedElts == ((1ULL << VWidth) -1))
-      return 0;
-    
-    const Type *EltTy = cast<VectorType>(V->getType())->getElementType();
-    Constant *Zero = Constant::getNullValue(EltTy);
-    Constant *Undef = UndefValue::get(EltTy);
-    std::vector<Constant*> Elts;
-    for (unsigned i = 0; i != VWidth; ++i) {
-      Constant *Elt = DemandedElts[i] ? Zero : Undef;
-      Elts.push_back(Elt);
-    }
-    UndefElts = DemandedElts ^ EltMask;
-    return ConstantVector::get(Elts);
-  }
-  
-  // Limit search depth.
-  if (Depth == 10)
-    return 0;
-
-  // If multiple users are using the root value, procede with
-  // simplification conservatively assuming that all elements
-  // are needed.
-  if (!V->hasOneUse()) {
-    // Quit if we find multiple users of a non-root value though.
-    // They'll be handled when it's their turn to be visited by
-    // the main instcombine process.
-    if (Depth != 0)
-      // TODO: Just compute the UndefElts information recursively.
-      return 0;
-
-    // Conservatively assume that all elements are needed.
-    DemandedElts = EltMask;
-  }
-  
-  Instruction *I = dyn_cast<Instruction>(V);
-  if (!I) return 0;        // Only analyze instructions.
-  
-  bool MadeChange = false;
-  APInt UndefElts2(VWidth, 0);
-  Value *TmpV;
-  switch (I->getOpcode()) {
-  default: break;
-    
-  case Instruction::InsertElement: {
-    // If this is a variable index, we don't know which element it overwrites.
-    // demand exactly the same input as we produce.
-    ConstantInt *Idx = dyn_cast<ConstantInt>(I->getOperand(2));
-    if (Idx == 0) {
-      // Note that we can't propagate undef elt info, because we don't know
-      // which elt is getting updated.
-      TmpV = SimplifyDemandedVectorElts(I->getOperand(0), DemandedElts,
-                                        UndefElts2, Depth+1);
-      if (TmpV) { I->setOperand(0, TmpV); MadeChange = true; }
-      break;
-    }
-    
-    // If this is inserting an element that isn't demanded, remove this
-    // insertelement.
-    unsigned IdxNo = Idx->getZExtValue();
-    if (IdxNo >= VWidth || !DemandedElts[IdxNo]) {
-      Worklist.Add(I);
-      return I->getOperand(0);
-    }
-    
-    // Otherwise, the element inserted overwrites whatever was there, so the
-    // input demanded set is simpler than the output set.
-    APInt DemandedElts2 = DemandedElts;
-    DemandedElts2.clear(IdxNo);
-    TmpV = SimplifyDemandedVectorElts(I->getOperand(0), DemandedElts2,
-                                      UndefElts, Depth+1);
-    if (TmpV) { I->setOperand(0, TmpV); MadeChange = true; }
-
-    // The inserted element is defined.
-    UndefElts.clear(IdxNo);
-    break;
-  }
-  case Instruction::ShuffleVector: {
-    ShuffleVectorInst *Shuffle = cast<ShuffleVectorInst>(I);
-    uint64_t LHSVWidth =
-      cast<VectorType>(Shuffle->getOperand(0)->getType())->getNumElements();
-    APInt LeftDemanded(LHSVWidth, 0), RightDemanded(LHSVWidth, 0);
-    for (unsigned i = 0; i < VWidth; i++) {
-      if (DemandedElts[i]) {
-        unsigned MaskVal = Shuffle->getMaskValue(i);
-        if (MaskVal != -1u) {
-          assert(MaskVal < LHSVWidth * 2 &&
-                 "shufflevector mask index out of range!");
-          if (MaskVal < LHSVWidth)
-            LeftDemanded.set(MaskVal);
-          else
-            RightDemanded.set(MaskVal - LHSVWidth);
-        }
-      }
-    }
-
-    APInt UndefElts4(LHSVWidth, 0);
-    TmpV = SimplifyDemandedVectorElts(I->getOperand(0), LeftDemanded,
-                                      UndefElts4, Depth+1);
-    if (TmpV) { I->setOperand(0, TmpV); MadeChange = true; }
-
-    APInt UndefElts3(LHSVWidth, 0);
-    TmpV = SimplifyDemandedVectorElts(I->getOperand(1), RightDemanded,
-                                      UndefElts3, Depth+1);
-    if (TmpV) { I->setOperand(1, TmpV); MadeChange = true; }
-
-    bool NewUndefElts = false;
-    for (unsigned i = 0; i < VWidth; i++) {
-      unsigned MaskVal = Shuffle->getMaskValue(i);
-      if (MaskVal == -1u) {
-        UndefElts.set(i);
-      } else if (MaskVal < LHSVWidth) {
-        if (UndefElts4[MaskVal]) {
-          NewUndefElts = true;
-          UndefElts.set(i);
-        }
-      } else {
-        if (UndefElts3[MaskVal - LHSVWidth]) {
-          NewUndefElts = true;
-          UndefElts.set(i);
-        }
-      }
-    }
-
-    if (NewUndefElts) {
-      // Add additional discovered undefs.
-      std::vector<Constant*> Elts;
-      for (unsigned i = 0; i < VWidth; ++i) {
-        if (UndefElts[i])
-          Elts.push_back(UndefValue::get(Type::getInt32Ty(*Context)));
-        else
-          Elts.push_back(ConstantInt::get(Type::getInt32Ty(*Context),
-                                          Shuffle->getMaskValue(i)));
-      }
-      I->setOperand(2, ConstantVector::get(Elts));
-      MadeChange = true;
-    }
-    break;
-  }
-  case Instruction::BitCast: {
-    // Vector->vector casts only.
-    const VectorType *VTy = dyn_cast<VectorType>(I->getOperand(0)->getType());
-    if (!VTy) break;
-    unsigned InVWidth = VTy->getNumElements();
-    APInt InputDemandedElts(InVWidth, 0);
-    unsigned Ratio;
-
-    if (VWidth == InVWidth) {
-      // If we are converting from <4 x i32> -> <4 x f32>, we demand the same
-      // elements as are demanded of us.
-      Ratio = 1;
-      InputDemandedElts = DemandedElts;
-    } else if (VWidth > InVWidth) {
-      // Untested so far.
-      break;
-      
-      // If there are more elements in the result than there are in the source,
-      // then an input element is live if any of the corresponding output
-      // elements are live.
-      Ratio = VWidth/InVWidth;
-      for (unsigned OutIdx = 0; OutIdx != VWidth; ++OutIdx) {
-        if (DemandedElts[OutIdx])
-          InputDemandedElts.set(OutIdx/Ratio);
-      }
-    } else {
-      // Untested so far.
-      break;
-      
-      // If there are more elements in the source than there are in the result,
-      // then an input element is live if the corresponding output element is
-      // live.
-      Ratio = InVWidth/VWidth;
-      for (unsigned InIdx = 0; InIdx != InVWidth; ++InIdx)
-        if (DemandedElts[InIdx/Ratio])
-          InputDemandedElts.set(InIdx);
-    }
-    
-    // div/rem demand all inputs, because they don't want divide by zero.
-    TmpV = SimplifyDemandedVectorElts(I->getOperand(0), InputDemandedElts,
-                                      UndefElts2, Depth+1);
-    if (TmpV) {
-      I->setOperand(0, TmpV);
-      MadeChange = true;
-    }
-    
-    UndefElts = UndefElts2;
-    if (VWidth > InVWidth) {
-      llvm_unreachable("Unimp");
-      // If there are more elements in the result than there are in the source,
-      // then an output element is undef if the corresponding input element is
-      // undef.
-      for (unsigned OutIdx = 0; OutIdx != VWidth; ++OutIdx)
-        if (UndefElts2[OutIdx/Ratio])
-          UndefElts.set(OutIdx);
-    } else if (VWidth < InVWidth) {
-      llvm_unreachable("Unimp");
-      // If there are more elements in the source than there are in the result,
-      // then a result element is undef if all of the corresponding input
-      // elements are undef.
-      UndefElts = ~0ULL >> (64-VWidth);  // Start out all undef.
-      for (unsigned InIdx = 0; InIdx != InVWidth; ++InIdx)
-        if (!UndefElts2[InIdx])            // Not undef?
-          UndefElts.clear(InIdx/Ratio);    // Clear undef bit.
-    }
-    break;
-  }
-  case Instruction::And:
-  case Instruction::Or:
-  case Instruction::Xor:
-  case Instruction::Add:
-  case Instruction::Sub:
-  case Instruction::Mul:
-    // div/rem demand all inputs, because they don't want divide by zero.
-    TmpV = SimplifyDemandedVectorElts(I->getOperand(0), DemandedElts,
-                                      UndefElts, Depth+1);
-    if (TmpV) { I->setOperand(0, TmpV); MadeChange = true; }
-    TmpV = SimplifyDemandedVectorElts(I->getOperand(1), DemandedElts,
-                                      UndefElts2, Depth+1);
-    if (TmpV) { I->setOperand(1, TmpV); MadeChange = true; }
-      
-    // Output elements are undefined if both are undefined.  Consider things
-    // like undef&0.  The result is known zero, not undef.
-    UndefElts &= UndefElts2;
-    break;
-    
-  case Instruction::Call: {
-    IntrinsicInst *II = dyn_cast<IntrinsicInst>(I);
-    if (!II) break;
-    switch (II->getIntrinsicID()) {
-    default: break;
-      
-    // Binary vector operations that work column-wise.  A dest element is a
-    // function of the corresponding input elements from the two inputs.
-    case Intrinsic::x86_sse_sub_ss:
-    case Intrinsic::x86_sse_mul_ss:
-    case Intrinsic::x86_sse_min_ss:
-    case Intrinsic::x86_sse_max_ss:
-    case Intrinsic::x86_sse2_sub_sd:
-    case Intrinsic::x86_sse2_mul_sd:
-    case Intrinsic::x86_sse2_min_sd:
-    case Intrinsic::x86_sse2_max_sd:
-      TmpV = SimplifyDemandedVectorElts(II->getOperand(1), DemandedElts,
-                                        UndefElts, Depth+1);
-      if (TmpV) { II->setOperand(1, TmpV); MadeChange = true; }
-      TmpV = SimplifyDemandedVectorElts(II->getOperand(2), DemandedElts,
-                                        UndefElts2, Depth+1);
-      if (TmpV) { II->setOperand(2, TmpV); MadeChange = true; }
-
-      // If only the low elt is demanded and this is a scalarizable intrinsic,
-      // scalarize it now.
-      if (DemandedElts == 1) {
-        switch (II->getIntrinsicID()) {
-        default: break;
-        case Intrinsic::x86_sse_sub_ss:
-        case Intrinsic::x86_sse_mul_ss:
-        case Intrinsic::x86_sse2_sub_sd:
-        case Intrinsic::x86_sse2_mul_sd:
-          // TODO: Lower MIN/MAX/ABS/etc
-          Value *LHS = II->getOperand(1);
-          Value *RHS = II->getOperand(2);
-          // Extract the element as scalars.
-          LHS = InsertNewInstBefore(ExtractElementInst::Create(LHS, 
-            ConstantInt::get(Type::getInt32Ty(*Context), 0U, false), "tmp"), *II);
-          RHS = InsertNewInstBefore(ExtractElementInst::Create(RHS,
-            ConstantInt::get(Type::getInt32Ty(*Context), 0U, false), "tmp"), *II);
-          
-          switch (II->getIntrinsicID()) {
-          default: llvm_unreachable("Case stmts out of sync!");
-          case Intrinsic::x86_sse_sub_ss:
-          case Intrinsic::x86_sse2_sub_sd:
-            TmpV = InsertNewInstBefore(BinaryOperator::CreateFSub(LHS, RHS,
-                                                        II->getName()), *II);
-            break;
-          case Intrinsic::x86_sse_mul_ss:
-          case Intrinsic::x86_sse2_mul_sd:
-            TmpV = InsertNewInstBefore(BinaryOperator::CreateFMul(LHS, RHS,
-                                                         II->getName()), *II);
-            break;
-          }
-          
-          Instruction *New =
-            InsertElementInst::Create(
-              UndefValue::get(II->getType()), TmpV,
-              ConstantInt::get(Type::getInt32Ty(*Context), 0U, false), II->getName());
-          InsertNewInstBefore(New, *II);
-          return New;
-        }            
-      }
-        
-      // Output elements are undefined if both are undefined.  Consider things
-      // like undef&0.  The result is known zero, not undef.
-      UndefElts &= UndefElts2;
-      break;
-    }
-    break;
-  }
-  }
-  return MadeChange ? I : 0;
-}
-
-
-/// AssociativeOpt - Perform an optimization on an associative operator.  This
-/// function is designed to check a chain of associative operators for a
-/// potential to apply a certain optimization.  Since the optimization may be
-/// applicable if the expression was reassociated, this checks the chain, then
-/// reassociates the expression as necessary to expose the optimization
-/// opportunity.  This makes use of a special Functor, which must define
-/// 'shouldApply' and 'apply' methods.
-///
-template<typename Functor>
-static Instruction *AssociativeOpt(BinaryOperator &Root, const Functor &F) {
-  unsigned Opcode = Root.getOpcode();
-  Value *LHS = Root.getOperand(0);
-
-  // Quick check, see if the immediate LHS matches...
-  if (F.shouldApply(LHS))
-    return F.apply(Root);
-
-  // Otherwise, if the LHS is not of the same opcode as the root, return.
-  Instruction *LHSI = dyn_cast<Instruction>(LHS);
-  while (LHSI && LHSI->getOpcode() == Opcode && LHSI->hasOneUse()) {
-    // Should we apply this transform to the RHS?
-    bool ShouldApply = F.shouldApply(LHSI->getOperand(1));
-
-    // If not to the RHS, check to see if we should apply to the LHS...
-    if (!ShouldApply && F.shouldApply(LHSI->getOperand(0))) {
-      cast<BinaryOperator>(LHSI)->swapOperands();   // Make the LHS the RHS
-      ShouldApply = true;
-    }
-
-    // If the functor wants to apply the optimization to the RHS of LHSI,
-    // reassociate the expression from ((? op A) op B) to (? op (A op B))
-    if (ShouldApply) {
-      // Now all of the instructions are in the current basic block, go ahead
-      // and perform the reassociation.
-      Instruction *TmpLHSI = cast<Instruction>(Root.getOperand(0));
-
-      // First move the selected RHS to the LHS of the root...
-      Root.setOperand(0, LHSI->getOperand(1));
-
-      // Make what used to be the LHS of the root be the user of the root...
-      Value *ExtraOperand = TmpLHSI->getOperand(1);
-      if (&Root == TmpLHSI) {
-        Root.replaceAllUsesWith(Constant::getNullValue(TmpLHSI->getType()));
-        return 0;
-      }
-      Root.replaceAllUsesWith(TmpLHSI);          // Users now use TmpLHSI
-      TmpLHSI->setOperand(1, &Root);             // TmpLHSI now uses the root
-      BasicBlock::iterator ARI = &Root; ++ARI;
-      TmpLHSI->moveBefore(ARI);                  // Move TmpLHSI to after Root
-      ARI = Root;
-
-      // Now propagate the ExtraOperand down the chain of instructions until we
-      // get to LHSI.
-      while (TmpLHSI != LHSI) {
-        Instruction *NextLHSI = cast<Instruction>(TmpLHSI->getOperand(0));
-        // Move the instruction to immediately before the chain we are
-        // constructing to avoid breaking dominance properties.
-        NextLHSI->moveBefore(ARI);
-        ARI = NextLHSI;
-
-        Value *NextOp = NextLHSI->getOperand(1);
-        NextLHSI->setOperand(1, ExtraOperand);
-        TmpLHSI = NextLHSI;
-        ExtraOperand = NextOp;
-      }
-
-      // Now that the instructions are reassociated, have the functor perform
-      // the transformation...
-      return F.apply(Root);
-    }
-
-    LHSI = dyn_cast<Instruction>(LHSI->getOperand(0));
-  }
-  return 0;
-}
-
-namespace {
-
-// AddRHS - Implements: X + X --> X << 1
-struct AddRHS {
-  Value *RHS;
-  explicit AddRHS(Value *rhs) : RHS(rhs) {}
-  bool shouldApply(Value *LHS) const { return LHS == RHS; }
-  Instruction *apply(BinaryOperator &Add) const {
-    return BinaryOperator::CreateShl(Add.getOperand(0),
-                                     ConstantInt::get(Add.getType(), 1));
-  }
-};
-
-// AddMaskingAnd - Implements (A & C1)+(B & C2) --> (A & C1)|(B & C2)
-//                 iff C1&C2 == 0
-struct AddMaskingAnd {
-  Constant *C2;
-  explicit AddMaskingAnd(Constant *c) : C2(c) {}
-  bool shouldApply(Value *LHS) const {
-    ConstantInt *C1;
-    return match(LHS, m_And(m_Value(), m_ConstantInt(C1))) &&
-           ConstantExpr::getAnd(C1, C2)->isNullValue();
-  }
-  Instruction *apply(BinaryOperator &Add) const {
-    return BinaryOperator::CreateOr(Add.getOperand(0), Add.getOperand(1));
-  }
-};
-
-}
-
-static Value *FoldOperationIntoSelectOperand(Instruction &I, Value *SO,
-                                             InstCombiner *IC) {
-  if (CastInst *CI = dyn_cast<CastInst>(&I))
-    return IC->Builder->CreateCast(CI->getOpcode(), SO, I.getType());
-
-  // Figure out if the constant is the left or the right argument.
-  bool ConstIsRHS = isa<Constant>(I.getOperand(1));
-  Constant *ConstOperand = cast<Constant>(I.getOperand(ConstIsRHS));
-
-  if (Constant *SOC = dyn_cast<Constant>(SO)) {
-    if (ConstIsRHS)
-      return ConstantExpr::get(I.getOpcode(), SOC, ConstOperand);
-    return ConstantExpr::get(I.getOpcode(), ConstOperand, SOC);
-  }
-
-  Value *Op0 = SO, *Op1 = ConstOperand;
-  if (!ConstIsRHS)
-    std::swap(Op0, Op1);
-  
-  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(&I))
-    return IC->Builder->CreateBinOp(BO->getOpcode(), Op0, Op1,
-                                    SO->getName()+".op");
-  if (ICmpInst *CI = dyn_cast<ICmpInst>(&I))
-    return IC->Builder->CreateICmp(CI->getPredicate(), Op0, Op1,
-                                   SO->getName()+".cmp");
-  if (FCmpInst *CI = dyn_cast<FCmpInst>(&I))
-    return IC->Builder->CreateICmp(CI->getPredicate(), Op0, Op1,
-                                   SO->getName()+".cmp");
-  llvm_unreachable("Unknown binary instruction type!");
-}
-
-// FoldOpIntoSelect - Given an instruction with a select as one operand and a
-// constant as the other operand, try to fold the binary operator into the
-// select arguments.  This also works for Cast instructions, which obviously do
-// not have a second operand.
-static Instruction *FoldOpIntoSelect(Instruction &Op, SelectInst *SI,
-                                     InstCombiner *IC) {
-  // Don't modify shared select instructions
-  if (!SI->hasOneUse()) return 0;
-  Value *TV = SI->getOperand(1);
-  Value *FV = SI->getOperand(2);
-
-  if (isa<Constant>(TV) || isa<Constant>(FV)) {
-    // Bool selects with constant operands can be folded to logical ops.
-    if (SI->getType() == Type::getInt1Ty(*IC->getContext())) return 0;
-
-    Value *SelectTrueVal = FoldOperationIntoSelectOperand(Op, TV, IC);
-    Value *SelectFalseVal = FoldOperationIntoSelectOperand(Op, FV, IC);
-
-    return SelectInst::Create(SI->getCondition(), SelectTrueVal,
-                              SelectFalseVal);
-  }
-  return 0;
-}
-
-
-/// FoldOpIntoPhi - Given a binary operator, cast instruction, or select which
-/// has a PHI node as operand #0, see if we can fold the instruction into the
-/// PHI (which is only possible if all operands to the PHI are constants).
-///
-/// If AllowAggressive is true, FoldOpIntoPhi will allow certain transforms
-/// that would normally be unprofitable because they strongly encourage jump
-/// threading.
-Instruction *InstCombiner::FoldOpIntoPhi(Instruction &I,
-                                         bool AllowAggressive) {
-  AllowAggressive = false;
-  PHINode *PN = cast<PHINode>(I.getOperand(0));
-  unsigned NumPHIValues = PN->getNumIncomingValues();
-  if (NumPHIValues == 0 ||
-      // We normally only transform phis with a single use, unless we're trying
-      // hard to make jump threading happen.
-      (!PN->hasOneUse() && !AllowAggressive))
-    return 0;
-  
-  
-  // Check to see if all of the operands of the PHI are simple constants
-  // (constantint/constantfp/undef).  If there is one non-constant value,
-  // remember the BB it is in.  If there is more than one or if *it* is a PHI,
-  // bail out.  We don't do arbitrary constant expressions here because moving
-  // their computation can be expensive without a cost model.
-  BasicBlock *NonConstBB = 0;
-  for (unsigned i = 0; i != NumPHIValues; ++i)
-    if (!isa<Constant>(PN->getIncomingValue(i)) ||
-        isa<ConstantExpr>(PN->getIncomingValue(i))) {
-      if (NonConstBB) return 0;  // More than one non-const value.
-      if (isa<PHINode>(PN->getIncomingValue(i))) return 0;  // Itself a phi.
-      NonConstBB = PN->getIncomingBlock(i);
-      
-      // If the incoming non-constant value is in I's block, we have an infinite
-      // loop.
-      if (NonConstBB == I.getParent())
-        return 0;
-    }
-  
-  // If there is exactly one non-constant value, we can insert a copy of the
-  // operation in that block.  However, if this is a critical edge, we would be
-  // inserting the computation one some other paths (e.g. inside a loop).  Only
-  // do this if the pred block is unconditionally branching into the phi block.
-  if (NonConstBB != 0 && !AllowAggressive) {
-    BranchInst *BI = dyn_cast<BranchInst>(NonConstBB->getTerminator());
-    if (!BI || !BI->isUnconditional()) return 0;
-  }
-
-  // Okay, we can do the transformation: create the new PHI node.
-  PHINode *NewPN = PHINode::Create(I.getType(), "");
-  NewPN->reserveOperandSpace(PN->getNumOperands()/2);
-  InsertNewInstBefore(NewPN, *PN);
-  NewPN->takeName(PN);
-
-  // Next, add all of the operands to the PHI.
-  if (SelectInst *SI = dyn_cast<SelectInst>(&I)) {
-    // We only currently try to fold the condition of a select when it is a phi,
-    // not the true/false values.
-    Value *TrueV = SI->getTrueValue();
-    Value *FalseV = SI->getFalseValue();
-    BasicBlock *PhiTransBB = PN->getParent();
-    for (unsigned i = 0; i != NumPHIValues; ++i) {
-      BasicBlock *ThisBB = PN->getIncomingBlock(i);
-      Value *TrueVInPred = TrueV->DoPHITranslation(PhiTransBB, ThisBB);
-      Value *FalseVInPred = FalseV->DoPHITranslation(PhiTransBB, ThisBB);
-      Value *InV = 0;
-      if (Constant *InC = dyn_cast<Constant>(PN->getIncomingValue(i))) {
-        InV = InC->isNullValue() ? FalseVInPred : TrueVInPred;
-      } else {
-        assert(PN->getIncomingBlock(i) == NonConstBB);
-        InV = SelectInst::Create(PN->getIncomingValue(i), TrueVInPred,
-                                 FalseVInPred,
-                                 "phitmp", NonConstBB->getTerminator());
-        Worklist.Add(cast<Instruction>(InV));
-      }
-      NewPN->addIncoming(InV, ThisBB);
-    }
-  } else if (I.getNumOperands() == 2) {
-    Constant *C = cast<Constant>(I.getOperand(1));
-    for (unsigned i = 0; i != NumPHIValues; ++i) {
-      Value *InV = 0;
-      if (Constant *InC = dyn_cast<Constant>(PN->getIncomingValue(i))) {
-        if (CmpInst *CI = dyn_cast<CmpInst>(&I))
-          InV = ConstantExpr::getCompare(CI->getPredicate(), InC, C);
-        else
-          InV = ConstantExpr::get(I.getOpcode(), InC, C);
-      } else {
-        assert(PN->getIncomingBlock(i) == NonConstBB);
-        if (BinaryOperator *BO = dyn_cast<BinaryOperator>(&I)) 
-          InV = BinaryOperator::Create(BO->getOpcode(),
-                                       PN->getIncomingValue(i), C, "phitmp",
-                                       NonConstBB->getTerminator());
-        else if (CmpInst *CI = dyn_cast<CmpInst>(&I))
-          InV = CmpInst::Create(CI->getOpcode(),
-                                CI->getPredicate(),
-                                PN->getIncomingValue(i), C, "phitmp",
-                                NonConstBB->getTerminator());
-        else
-          llvm_unreachable("Unknown binop!");
-        
-        Worklist.Add(cast<Instruction>(InV));
-      }
-      NewPN->addIncoming(InV, PN->getIncomingBlock(i));
-    }
-  } else { 
-    CastInst *CI = cast<CastInst>(&I);
-    const Type *RetTy = CI->getType();
-    for (unsigned i = 0; i != NumPHIValues; ++i) {
-      Value *InV;
-      if (Constant *InC = dyn_cast<Constant>(PN->getIncomingValue(i))) {
-        InV = ConstantExpr::getCast(CI->getOpcode(), InC, RetTy);
-      } else {
-        assert(PN->getIncomingBlock(i) == NonConstBB);
-        InV = CastInst::Create(CI->getOpcode(), PN->getIncomingValue(i), 
-                               I.getType(), "phitmp", 
-                               NonConstBB->getTerminator());
-        Worklist.Add(cast<Instruction>(InV));
-      }
-      NewPN->addIncoming(InV, PN->getIncomingBlock(i));
-    }
-  }
-  return ReplaceInstUsesWith(I, NewPN);
-}
-
-
-/// WillNotOverflowSignedAdd - Return true if we can prove that:
-///    (sext (add LHS, RHS))  === (add (sext LHS), (sext RHS))
-/// This basically requires proving that the add in the original type would not
-/// overflow to change the sign bit or have a carry out.
-bool InstCombiner::WillNotOverflowSignedAdd(Value *LHS, Value *RHS) {
-  // There are different heuristics we can use for this.  Here are some simple
-  // ones.
-  
-  // Add has the property that adding any two 2's complement numbers can only 
-  // have one carry bit which can change a sign.  As such, if LHS and RHS each
-  // have at least two sign bits, we know that the addition of the two values
-  // will sign extend fine.
-  if (ComputeNumSignBits(LHS) > 1 && ComputeNumSignBits(RHS) > 1)
-    return true;
-  
-  
-  // If one of the operands only has one non-zero bit, and if the other operand
-  // has a known-zero bit in a more significant place than it (not including the
-  // sign bit) the ripple may go up to and fill the zero, but won't change the
-  // sign.  For example, (X & ~4) + 1.
-  
-  // TODO: Implement.
-  
-  return false;
-}
-
-
-Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
-  bool Changed = SimplifyCommutative(I);
-  Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
-
-  if (Value *V = SimplifyAddInst(LHS, RHS, I.hasNoSignedWrap(),
-                                 I.hasNoUnsignedWrap(), TD))
-    return ReplaceInstUsesWith(I, V);
-
-  
-  if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
-    if (ConstantInt *CI = dyn_cast<ConstantInt>(RHSC)) {
-      // X + (signbit) --> X ^ signbit
-      const APInt& Val = CI->getValue();
-      uint32_t BitWidth = Val.getBitWidth();
-      if (Val == APInt::getSignBit(BitWidth))
-        return BinaryOperator::CreateXor(LHS, RHS);
-      
-      // See if SimplifyDemandedBits can simplify this.  This handles stuff like
-      // (X & 254)+1 -> (X&254)|1
-      if (SimplifyDemandedInstructionBits(I))
-        return &I;
-
-      // zext(bool) + C -> bool ? C + 1 : C
-      if (ZExtInst *ZI = dyn_cast<ZExtInst>(LHS))
-        if (ZI->getSrcTy() == Type::getInt1Ty(*Context))
-          return SelectInst::Create(ZI->getOperand(0), AddOne(CI), CI);
-    }
-
-    if (isa<PHINode>(LHS))
-      if (Instruction *NV = FoldOpIntoPhi(I))
-        return NV;
-    
-    ConstantInt *XorRHS = 0;
-    Value *XorLHS = 0;
-    if (isa<ConstantInt>(RHSC) &&
-        match(LHS, m_Xor(m_Value(XorLHS), m_ConstantInt(XorRHS)))) {
-      uint32_t TySizeBits = I.getType()->getScalarSizeInBits();
-      const APInt& RHSVal = cast<ConstantInt>(RHSC)->getValue();
-      
-      uint32_t Size = TySizeBits / 2;
-      APInt C0080Val(APInt(TySizeBits, 1ULL).shl(Size - 1));
-      APInt CFF80Val(-C0080Val);
-      do {
-        if (TySizeBits > Size) {
-          // If we have ADD(XOR(AND(X, 0xFF), 0x80), 0xF..F80), it's a sext.
-          // If we have ADD(XOR(AND(X, 0xFF), 0xF..F80), 0x80), it's a sext.
-          if ((RHSVal == CFF80Val && XorRHS->getValue() == C0080Val) ||
-              (RHSVal == C0080Val && XorRHS->getValue() == CFF80Val)) {
-            // This is a sign extend if the top bits are known zero.
-            if (!MaskedValueIsZero(XorLHS, 
-                   APInt::getHighBitsSet(TySizeBits, TySizeBits - Size)))
-              Size = 0;  // Not a sign ext, but can't be any others either.
-            break;
-          }
-        }
-        Size >>= 1;
-        C0080Val = APIntOps::lshr(C0080Val, Size);
-        CFF80Val = APIntOps::ashr(CFF80Val, Size);
-      } while (Size >= 1);
-      
-      // FIXME: This shouldn't be necessary. When the backends can handle types
-      // with funny bit widths then this switch statement should be removed. It
-      // is just here to get the size of the "middle" type back up to something
-      // that the back ends can handle.
-      const Type *MiddleType = 0;
-      switch (Size) {
-        default: break;
-        case 32: MiddleType = Type::getInt32Ty(*Context); break;
-        case 16: MiddleType = Type::getInt16Ty(*Context); break;
-        case  8: MiddleType = Type::getInt8Ty(*Context); break;
-      }
-      if (MiddleType) {
-        Value *NewTrunc = Builder->CreateTrunc(XorLHS, MiddleType, "sext");
-        return new SExtInst(NewTrunc, I.getType(), I.getName());
-      }
-    }
-  }
-
-  if (I.getType() == Type::getInt1Ty(*Context))
-    return BinaryOperator::CreateXor(LHS, RHS);
-
-  // X + X --> X << 1
-  if (I.getType()->isInteger()) {
-    if (Instruction *Result = AssociativeOpt(I, AddRHS(RHS)))
-      return Result;
-
-    if (Instruction *RHSI = dyn_cast<Instruction>(RHS)) {
-      if (RHSI->getOpcode() == Instruction::Sub)
-        if (LHS == RHSI->getOperand(1))                   // A + (B - A) --> B
-          return ReplaceInstUsesWith(I, RHSI->getOperand(0));
-    }
-    if (Instruction *LHSI = dyn_cast<Instruction>(LHS)) {
-      if (LHSI->getOpcode() == Instruction::Sub)
-        if (RHS == LHSI->getOperand(1))                   // (B - A) + A --> B
-          return ReplaceInstUsesWith(I, LHSI->getOperand(0));
-    }
-  }
-
-  // -A + B  -->  B - A
-  // -A + -B  -->  -(A + B)
-  if (Value *LHSV = dyn_castNegVal(LHS)) {
-    if (LHS->getType()->isIntOrIntVector()) {
-      if (Value *RHSV = dyn_castNegVal(RHS)) {
-        Value *NewAdd = Builder->CreateAdd(LHSV, RHSV, "sum");
-        return BinaryOperator::CreateNeg(NewAdd);
-      }
-    }
-    
-    return BinaryOperator::CreateSub(RHS, LHSV);
-  }
-
-  // A + -B  -->  A - B
-  if (!isa<Constant>(RHS))
-    if (Value *V = dyn_castNegVal(RHS))
-      return BinaryOperator::CreateSub(LHS, V);
-
-
-  ConstantInt *C2;
-  if (Value *X = dyn_castFoldableMul(LHS, C2)) {
-    if (X == RHS)   // X*C + X --> X * (C+1)
-      return BinaryOperator::CreateMul(RHS, AddOne(C2));
-
-    // X*C1 + X*C2 --> X * (C1+C2)
-    ConstantInt *C1;
-    if (X == dyn_castFoldableMul(RHS, C1))
-      return BinaryOperator::CreateMul(X, ConstantExpr::getAdd(C1, C2));
-  }
-
-  // X + X*C --> X * (C+1)
-  if (dyn_castFoldableMul(RHS, C2) == LHS)
-    return BinaryOperator::CreateMul(LHS, AddOne(C2));
-
-  // X + ~X --> -1   since   ~X = -X-1
-  if (dyn_castNotVal(LHS) == RHS ||
-      dyn_castNotVal(RHS) == LHS)
-    return ReplaceInstUsesWith(I, Constant::getAllOnesValue(I.getType()));
-  
-
-  // (A & C1)+(B & C2) --> (A & C1)|(B & C2) iff C1&C2 == 0
-  if (match(RHS, m_And(m_Value(), m_ConstantInt(C2))))
-    if (Instruction *R = AssociativeOpt(I, AddMaskingAnd(C2)))
-      return R;
-  
-  // A+B --> A|B iff A and B have no bits set in common.
-  if (const IntegerType *IT = dyn_cast<IntegerType>(I.getType())) {
-    APInt Mask = APInt::getAllOnesValue(IT->getBitWidth());
-    APInt LHSKnownOne(IT->getBitWidth(), 0);
-    APInt LHSKnownZero(IT->getBitWidth(), 0);
-    ComputeMaskedBits(LHS, Mask, LHSKnownZero, LHSKnownOne);
-    if (LHSKnownZero != 0) {
-      APInt RHSKnownOne(IT->getBitWidth(), 0);
-      APInt RHSKnownZero(IT->getBitWidth(), 0);
-      ComputeMaskedBits(RHS, Mask, RHSKnownZero, RHSKnownOne);
-      
-      // No bits in common -> bitwise or.
-      if ((LHSKnownZero|RHSKnownZero).isAllOnesValue())
-        return BinaryOperator::CreateOr(LHS, RHS);
-    }
-  }
-
-  // W*X + Y*Z --> W * (X+Z)  iff W == Y
-  if (I.getType()->isIntOrIntVector()) {
-    Value *W, *X, *Y, *Z;
-    if (match(LHS, m_Mul(m_Value(W), m_Value(X))) &&
-        match(RHS, m_Mul(m_Value(Y), m_Value(Z)))) {
-      if (W != Y) {
-        if (W == Z) {
-          std::swap(Y, Z);
-        } else if (Y == X) {
-          std::swap(W, X);
-        } else if (X == Z) {
-          std::swap(Y, Z);
-          std::swap(W, X);
-        }
-      }
-
-      if (W == Y) {
-        Value *NewAdd = Builder->CreateAdd(X, Z, LHS->getName());
-        return BinaryOperator::CreateMul(W, NewAdd);
-      }
-    }
-  }
-
-  if (ConstantInt *CRHS = dyn_cast<ConstantInt>(RHS)) {
-    Value *X = 0;
-    if (match(LHS, m_Not(m_Value(X))))    // ~X + C --> (C-1) - X
-      return BinaryOperator::CreateSub(SubOne(CRHS), X);
-
-    // (X & FF00) + xx00  -> (X+xx00) & FF00
-    if (LHS->hasOneUse() &&
-        match(LHS, m_And(m_Value(X), m_ConstantInt(C2)))) {
-      Constant *Anded = ConstantExpr::getAnd(CRHS, C2);
-      if (Anded == CRHS) {
-        // See if all bits from the first bit set in the Add RHS up are included
-        // in the mask.  First, get the rightmost bit.
-        const APInt& AddRHSV = CRHS->getValue();
-
-        // Form a mask of all bits from the lowest bit added through the top.
-        APInt AddRHSHighBits(~((AddRHSV & -AddRHSV)-1));
-
-        // See if the and mask includes all of these bits.
-        APInt AddRHSHighBitsAnd(AddRHSHighBits & C2->getValue());
-
-        if (AddRHSHighBits == AddRHSHighBitsAnd) {
-          // Okay, the xform is safe.  Insert the new add pronto.
-          Value *NewAdd = Builder->CreateAdd(X, CRHS, LHS->getName());
-          return BinaryOperator::CreateAnd(NewAdd, C2);
-        }
-      }
-    }
-
-    // Try to fold constant add into select arguments.
-    if (SelectInst *SI = dyn_cast<SelectInst>(LHS))
-      if (Instruction *R = FoldOpIntoSelect(I, SI, this))
-        return R;
-  }
-
-  // add (select X 0 (sub n A)) A  -->  select X A n
-  {
-    SelectInst *SI = dyn_cast<SelectInst>(LHS);
-    Value *A = RHS;
-    if (!SI) {
-      SI = dyn_cast<SelectInst>(RHS);
-      A = LHS;
-    }
-    if (SI && SI->hasOneUse()) {
-      Value *TV = SI->getTrueValue();
-      Value *FV = SI->getFalseValue();
-      Value *N;
-
-      // Can we fold the add into the argument of the select?
-      // We check both true and false select arguments for a matching subtract.
-      if (match(FV, m_Zero()) &&
-          match(TV, m_Sub(m_Value(N), m_Specific(A))))
-        // Fold the add into the true select value.
-        return SelectInst::Create(SI->getCondition(), N, A);
-      if (match(TV, m_Zero()) &&
-          match(FV, m_Sub(m_Value(N), m_Specific(A))))
-        // Fold the add into the false select value.
-        return SelectInst::Create(SI->getCondition(), A, N);
-    }
-  }
-
-  // Check for (add (sext x), y), see if we can merge this into an
-  // integer add followed by a sext.
-  if (SExtInst *LHSConv = dyn_cast<SExtInst>(LHS)) {
-    // (add (sext x), cst) --> (sext (add x, cst'))
-    if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS)) {
-      Constant *CI = 
-        ConstantExpr::getTrunc(RHSC, LHSConv->getOperand(0)->getType());
-      if (LHSConv->hasOneUse() &&
-          ConstantExpr::getSExt(CI, I.getType()) == RHSC &&
-          WillNotOverflowSignedAdd(LHSConv->getOperand(0), CI)) {
-        // Insert the new, smaller add.
-        Value *NewAdd = Builder->CreateNSWAdd(LHSConv->getOperand(0), 
-                                              CI, "addconv");
-        return new SExtInst(NewAdd, I.getType());
-      }
-    }
-    
-    // (add (sext x), (sext y)) --> (sext (add int x, y))
-    if (SExtInst *RHSConv = dyn_cast<SExtInst>(RHS)) {
-      // Only do this if x/y have the same type, if at last one of them has a
-      // single use (so we don't increase the number of sexts), and if the
-      // integer add will not overflow.
-      if (LHSConv->getOperand(0)->getType()==RHSConv->getOperand(0)->getType()&&
-          (LHSConv->hasOneUse() || RHSConv->hasOneUse()) &&
-          WillNotOverflowSignedAdd(LHSConv->getOperand(0),
-                                   RHSConv->getOperand(0))) {
-        // Insert the new integer add.
-        Value *NewAdd = Builder->CreateNSWAdd(LHSConv->getOperand(0), 
-                                              RHSConv->getOperand(0), "addconv");
-        return new SExtInst(NewAdd, I.getType());
-      }
-    }
-  }
-
-  return Changed ? &I : 0;
-}
-
-Instruction *InstCombiner::visitFAdd(BinaryOperator &I) {
-  bool Changed = SimplifyCommutative(I);
-  Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
-
-  if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
-    // X + 0 --> X
-    if (ConstantFP *CFP = dyn_cast<ConstantFP>(RHSC)) {
-      if (CFP->isExactlyValue(ConstantFP::getNegativeZero
-                              (I.getType())->getValueAPF()))
-        return ReplaceInstUsesWith(I, LHS);
-    }
-
-    if (isa<PHINode>(LHS))
-      if (Instruction *NV = FoldOpIntoPhi(I))
-        return NV;
-  }
-
-  // -A + B  -->  B - A
-  // -A + -B  -->  -(A + B)
-  if (Value *LHSV = dyn_castFNegVal(LHS))
-    return BinaryOperator::CreateFSub(RHS, LHSV);
-
-  // A + -B  -->  A - B
-  if (!isa<Constant>(RHS))
-    if (Value *V = dyn_castFNegVal(RHS))
-      return BinaryOperator::CreateFSub(LHS, V);
-
-  // Check for X+0.0.  Simplify it to X if we know X is not -0.0.
-  if (ConstantFP *CFP = dyn_cast<ConstantFP>(RHS))
-    if (CFP->getValueAPF().isPosZero() && CannotBeNegativeZero(LHS))
-      return ReplaceInstUsesWith(I, LHS);
-
-  // Check for (add double (sitofp x), y), see if we can merge this into an
-  // integer add followed by a promotion.
-  if (SIToFPInst *LHSConv = dyn_cast<SIToFPInst>(LHS)) {
-    // (add double (sitofp x), fpcst) --> (sitofp (add int x, intcst))
-    // ... if the constant fits in the integer value.  This is useful for things
-    // like (double)(x & 1234) + 4.0 -> (double)((X & 1234)+4) which no longer
-    // requires a constant pool load, and generally allows the add to be better
-    // instcombined.
-    if (ConstantFP *CFP = dyn_cast<ConstantFP>(RHS)) {
-      Constant *CI = 
-      ConstantExpr::getFPToSI(CFP, LHSConv->getOperand(0)->getType());
-      if (LHSConv->hasOneUse() &&
-          ConstantExpr::getSIToFP(CI, I.getType()) == CFP &&
-          WillNotOverflowSignedAdd(LHSConv->getOperand(0), CI)) {
-        // Insert the new integer add.
-        Value *NewAdd = Builder->CreateNSWAdd(LHSConv->getOperand(0),
-                                              CI, "addconv");
-        return new SIToFPInst(NewAdd, I.getType());
-      }
-    }
-    
-    // (add double (sitofp x), (sitofp y)) --> (sitofp (add int x, y))
-    if (SIToFPInst *RHSConv = dyn_cast<SIToFPInst>(RHS)) {
-      // Only do this if x/y have the same type, if at last one of them has a
-      // single use (so we don't increase the number of int->fp conversions),
-      // and if the integer add will not overflow.
-      if (LHSConv->getOperand(0)->getType()==RHSConv->getOperand(0)->getType()&&
-          (LHSConv->hasOneUse() || RHSConv->hasOneUse()) &&
-          WillNotOverflowSignedAdd(LHSConv->getOperand(0),
-                                   RHSConv->getOperand(0))) {
-        // Insert the new integer add.
-        Value *NewAdd = Builder->CreateNSWAdd(LHSConv->getOperand(0), 
-                                              RHSConv->getOperand(0),"addconv");
-        return new SIToFPInst(NewAdd, I.getType());
-      }
-    }
-  }
-  
-  return Changed ? &I : 0;
-}
-
-
-/// EmitGEPOffset - Given a getelementptr instruction/constantexpr, emit the
-/// code necessary to compute the offset from the base pointer (without adding
-/// in the base pointer).  Return the result as a signed integer of intptr size.
-static Value *EmitGEPOffset(User *GEP, InstCombiner &IC) {
-  TargetData &TD = *IC.getTargetData();
-  gep_type_iterator GTI = gep_type_begin(GEP);
-  const Type *IntPtrTy = TD.getIntPtrType(GEP->getContext());
-  Value *Result = Constant::getNullValue(IntPtrTy);
-
-  // Build a mask for high order bits.
-  unsigned IntPtrWidth = TD.getPointerSizeInBits();
-  uint64_t PtrSizeMask = ~0ULL >> (64-IntPtrWidth);
-
-  for (User::op_iterator i = GEP->op_begin() + 1, e = GEP->op_end(); i != e;
-       ++i, ++GTI) {
-    Value *Op = *i;
-    uint64_t Size = TD.getTypeAllocSize(GTI.getIndexedType()) & PtrSizeMask;
-    if (ConstantInt *OpC = dyn_cast<ConstantInt>(Op)) {
-      if (OpC->isZero()) continue;
-      
-      // Handle a struct index, which adds its field offset to the pointer.
-      if (const StructType *STy = dyn_cast<StructType>(*GTI)) {
-        Size = TD.getStructLayout(STy)->getElementOffset(OpC->getZExtValue());
-        
-        Result = IC.Builder->CreateAdd(Result,
-                                       ConstantInt::get(IntPtrTy, Size),
-                                       GEP->getName()+".offs");
-        continue;
-      }
-      
-      Constant *Scale = ConstantInt::get(IntPtrTy, Size);
-      Constant *OC =
-              ConstantExpr::getIntegerCast(OpC, IntPtrTy, true /*SExt*/);
-      Scale = ConstantExpr::getMul(OC, Scale);
-      // Emit an add instruction.
-      Result = IC.Builder->CreateAdd(Result, Scale, GEP->getName()+".offs");
-      continue;
-    }
-    // Convert to correct type.
-    if (Op->getType() != IntPtrTy)
-      Op = IC.Builder->CreateIntCast(Op, IntPtrTy, true, Op->getName()+".c");
-    if (Size != 1) {
-      Constant *Scale = ConstantInt::get(IntPtrTy, Size);
-      // We'll let instcombine(mul) convert this to a shl if possible.
-      Op = IC.Builder->CreateMul(Op, Scale, GEP->getName()+".idx");
-    }
-
-    // Emit an add instruction.
-    Result = IC.Builder->CreateAdd(Op, Result, GEP->getName()+".offs");
-  }
-  return Result;
-}
-
-
-/// EvaluateGEPOffsetExpression - Return a value that can be used to compare
-/// the *offset* implied by a GEP to zero.  For example, if we have &A[i], we
-/// want to return 'i' for "icmp ne i, 0".  Note that, in general, indices can
-/// be complex, and scales are involved.  The above expression would also be
-/// legal to codegen as "icmp ne (i*4), 0" (assuming A is a pointer to i32).
-/// This later form is less amenable to optimization though, and we are allowed
-/// to generate the first by knowing that pointer arithmetic doesn't overflow.
-///
-/// If we can't emit an optimized form for this expression, this returns null.
-/// 
-static Value *EvaluateGEPOffsetExpression(User *GEP, Instruction &I,
-                                          InstCombiner &IC) {
-  TargetData &TD = *IC.getTargetData();
-  gep_type_iterator GTI = gep_type_begin(GEP);
-
-  // Check to see if this gep only has a single variable index.  If so, and if
-  // any constant indices are a multiple of its scale, then we can compute this
-  // in terms of the scale of the variable index.  For example, if the GEP
-  // implies an offset of "12 + i*4", then we can codegen this as "3 + i",
-  // because the expression will cross zero at the same point.
-  unsigned i, e = GEP->getNumOperands();
-  int64_t Offset = 0;
-  for (i = 1; i != e; ++i, ++GTI) {
-    if (ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(i))) {
-      // Compute the aggregate offset of constant indices.
-      if (CI->isZero()) continue;
-
-      // Handle a struct index, which adds its field offset to the pointer.
-      if (const StructType *STy = dyn_cast<StructType>(*GTI)) {
-        Offset += TD.getStructLayout(STy)->getElementOffset(CI->getZExtValue());
-      } else {
-        uint64_t Size = TD.getTypeAllocSize(GTI.getIndexedType());
-        Offset += Size*CI->getSExtValue();
-      }
-    } else {
-      // Found our variable index.
-      break;
-    }
-  }
-  
-  // If there are no variable indices, we must have a constant offset, just
-  // evaluate it the general way.
-  if (i == e) return 0;
-  
-  Value *VariableIdx = GEP->getOperand(i);
-  // Determine the scale factor of the variable element.  For example, this is
-  // 4 if the variable index is into an array of i32.
-  uint64_t VariableScale = TD.getTypeAllocSize(GTI.getIndexedType());
-  
-  // Verify that there are no other variable indices.  If so, emit the hard way.
-  for (++i, ++GTI; i != e; ++i, ++GTI) {
-    ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(i));
-    if (!CI) return 0;
-   
-    // Compute the aggregate offset of constant indices.
-    if (CI->isZero()) continue;
-    
-    // Handle a struct index, which adds its field offset to the pointer.
-    if (const StructType *STy = dyn_cast<StructType>(*GTI)) {
-      Offset += TD.getStructLayout(STy)->getElementOffset(CI->getZExtValue());
-    } else {
-      uint64_t Size = TD.getTypeAllocSize(GTI.getIndexedType());
-      Offset += Size*CI->getSExtValue();
-    }
-  }
-  
-  // Okay, we know we have a single variable index, which must be a
-  // pointer/array/vector index.  If there is no offset, life is simple, return
-  // the index.
-  unsigned IntPtrWidth = TD.getPointerSizeInBits();
-  if (Offset == 0) {
-    // Cast to intptrty in case a truncation occurs.  If an extension is needed,
-    // we don't need to bother extending: the extension won't affect where the
-    // computation crosses zero.
-    if (VariableIdx->getType()->getPrimitiveSizeInBits() > IntPtrWidth)
-      VariableIdx = new TruncInst(VariableIdx, 
-                                  TD.getIntPtrType(VariableIdx->getContext()),
-                                  VariableIdx->getName(), &I);
-    return VariableIdx;
-  }
-  
-  // Otherwise, there is an index.  The computation we will do will be modulo
-  // the pointer size, so get it.
-  uint64_t PtrSizeMask = ~0ULL >> (64-IntPtrWidth);
-  
-  Offset &= PtrSizeMask;
-  VariableScale &= PtrSizeMask;
-
-  // To do this transformation, any constant index must be a multiple of the
-  // variable scale factor.  For example, we can evaluate "12 + 4*i" as "3 + i",
-  // but we can't evaluate "10 + 3*i" in terms of i.  Check that the offset is a
-  // multiple of the variable scale.
-  int64_t NewOffs = Offset / (int64_t)VariableScale;
-  if (Offset != NewOffs*(int64_t)VariableScale)
-    return 0;
-
-  // Okay, we can do this evaluation.  Start by converting the index to intptr.
-  const Type *IntPtrTy = TD.getIntPtrType(VariableIdx->getContext());
-  if (VariableIdx->getType() != IntPtrTy)
-    VariableIdx = CastInst::CreateIntegerCast(VariableIdx, IntPtrTy,
-                                              true /*SExt*/, 
-                                              VariableIdx->getName(), &I);
-  Constant *OffsetVal = ConstantInt::get(IntPtrTy, NewOffs);
-  return BinaryOperator::CreateAdd(VariableIdx, OffsetVal, "offset", &I);
-}
-
-
-/// Optimize pointer differences into the same array into a size.  Consider:
-///  &A[10] - &A[0]: we should compile this to "10".  LHS/RHS are the pointer
-/// operands to the ptrtoint instructions for the LHS/RHS of the subtract.
-///
-Value *InstCombiner::OptimizePointerDifference(Value *LHS, Value *RHS,
-                                               const Type *Ty) {
-  assert(TD && "Must have target data info for this");
-  
-  // If LHS is a gep based on RHS or RHS is a gep based on LHS, we can optimize
-  // this.
-  bool Swapped;
-  GetElementPtrInst *GEP = 0;
-  ConstantExpr *CstGEP = 0;
-  
-  // TODO: Could also optimize &A[i] - &A[j] -> "i-j", and "&A.foo[i] - &A.foo".
-  // For now we require one side to be the base pointer "A" or a constant
-  // expression derived from it.
-  if (GetElementPtrInst *LHSGEP = dyn_cast<GetElementPtrInst>(LHS)) {
-    // (gep X, ...) - X
-    if (LHSGEP->getOperand(0) == RHS) {
-      GEP = LHSGEP;
-      Swapped = false;
-    } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(RHS)) {
-      // (gep X, ...) - (ce_gep X, ...)
-      if (CE->getOpcode() == Instruction::GetElementPtr &&
-          LHSGEP->getOperand(0) == CE->getOperand(0)) {
-        CstGEP = CE;
-        GEP = LHSGEP;
-        Swapped = false;
-      }
-    }
-  }
-  
-  if (GetElementPtrInst *RHSGEP = dyn_cast<GetElementPtrInst>(RHS)) {
-    // X - (gep X, ...)
-    if (RHSGEP->getOperand(0) == LHS) {
-      GEP = RHSGEP;
-      Swapped = true;
-    } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(LHS)) {
-      // (ce_gep X, ...) - (gep X, ...)
-      if (CE->getOpcode() == Instruction::GetElementPtr &&
-          RHSGEP->getOperand(0) == CE->getOperand(0)) {
-        CstGEP = CE;
-        GEP = RHSGEP;
-        Swapped = true;
-      }
-    }
-  }
-  
-  if (GEP == 0)
-    return 0;
-  
-  // Emit the offset of the GEP and an intptr_t.
-  Value *Result = EmitGEPOffset(GEP, *this);
-  
-  // If we had a constant expression GEP on the other side offsetting the
-  // pointer, subtract it from the offset we have.
-  if (CstGEP) {
-    Value *CstOffset = EmitGEPOffset(CstGEP, *this);
-    Result = Builder->CreateSub(Result, CstOffset);
-  }
-  
-
-  // If we have p - gep(p, ...)  then we have to negate the result.
-  if (Swapped)
-    Result = Builder->CreateNeg(Result, "diff.neg");
-
-  return Builder->CreateIntCast(Result, Ty, true);
-}
-
-
-Instruction *InstCombiner::visitSub(BinaryOperator &I) {
-  Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
-  if (Op0 == Op1)                        // sub X, X  -> 0
-    return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
-
-  // If this is a 'B = x-(-A)', change to B = x+A.  This preserves NSW/NUW.
-  if (Value *V = dyn_castNegVal(Op1)) {
-    BinaryOperator *Res = BinaryOperator::CreateAdd(Op0, V);
-    Res->setHasNoSignedWrap(I.hasNoSignedWrap());
-    Res->setHasNoUnsignedWrap(I.hasNoUnsignedWrap());
-    return Res;
-  }
-
-  if (isa<UndefValue>(Op0))
-    return ReplaceInstUsesWith(I, Op0);    // undef - X -> undef
-  if (isa<UndefValue>(Op1))
-    return ReplaceInstUsesWith(I, Op1);    // X - undef -> undef
-  if (I.getType() == Type::getInt1Ty(*Context))
-    return BinaryOperator::CreateXor(Op0, Op1);
-  
-  if (ConstantInt *C = dyn_cast<ConstantInt>(Op0)) {
-    // Replace (-1 - A) with (~A).
-    if (C->isAllOnesValue())
-      return BinaryOperator::CreateNot(Op1);
-
-    // C - ~X == X + (1+C)
-    Value *X = 0;
-    if (match(Op1, m_Not(m_Value(X))))
-      return BinaryOperator::CreateAdd(X, AddOne(C));
-
-    // -(X >>u 31) -> (X >>s 31)
-    // -(X >>s 31) -> (X >>u 31)
-    if (C->isZero()) {
-      if (BinaryOperator *SI = dyn_cast<BinaryOperator>(Op1)) {
-        if (SI->getOpcode() == Instruction::LShr) {
-          if (ConstantInt *CU = dyn_cast<ConstantInt>(SI->getOperand(1))) {
-            // Check to see if we are shifting out everything but the sign bit.
-            if (CU->getLimitedValue(SI->getType()->getPrimitiveSizeInBits()) ==
-                SI->getType()->getPrimitiveSizeInBits()-1) {
-              // Ok, the transformation is safe.  Insert AShr.
-              return BinaryOperator::Create(Instruction::AShr, 
-                                          SI->getOperand(0), CU, SI->getName());
-            }
-          }
-        } else if (SI->getOpcode() == Instruction::AShr) {
-          if (ConstantInt *CU = dyn_cast<ConstantInt>(SI->getOperand(1))) {
-            // Check to see if we are shifting out everything but the sign bit.
-            if (CU->getLimitedValue(SI->getType()->getPrimitiveSizeInBits()) ==
-                SI->getType()->getPrimitiveSizeInBits()-1) {
-              // Ok, the transformation is safe.  Insert LShr. 
-              return BinaryOperator::CreateLShr(
-                                          SI->getOperand(0), CU, SI->getName());
-            }
-          }
-        }
-      }
-    }
-
-    // Try to fold constant sub into select arguments.
-    if (SelectInst *SI = dyn_cast<SelectInst>(Op1))
-      if (Instruction *R = FoldOpIntoSelect(I, SI, this))
-        return R;
-
-    // C - zext(bool) -> bool ? C - 1 : C
-    if (ZExtInst *ZI = dyn_cast<ZExtInst>(Op1))
-      if (ZI->getSrcTy() == Type::getInt1Ty(*Context))
-        return SelectInst::Create(ZI->getOperand(0), SubOne(C), C);
-  }
-
-  if (BinaryOperator *Op1I = dyn_cast<BinaryOperator>(Op1)) {
-    if (Op1I->getOpcode() == Instruction::Add) {
-      if (Op1I->getOperand(0) == Op0)              // X-(X+Y) == -Y
-        return BinaryOperator::CreateNeg(Op1I->getOperand(1),
-                                         I.getName());
-      else if (Op1I->getOperand(1) == Op0)         // X-(Y+X) == -Y
-        return BinaryOperator::CreateNeg(Op1I->getOperand(0),
-                                         I.getName());
-      else if (ConstantInt *CI1 = dyn_cast<ConstantInt>(I.getOperand(0))) {
-        if (ConstantInt *CI2 = dyn_cast<ConstantInt>(Op1I->getOperand(1)))
-          // C1-(X+C2) --> (C1-C2)-X
-          return BinaryOperator::CreateSub(
-            ConstantExpr::getSub(CI1, CI2), Op1I->getOperand(0));
-      }
-    }
-
-    if (Op1I->hasOneUse()) {
-      // Replace (x - (y - z)) with (x + (z - y)) if the (y - z) subexpression
-      // is not used by anyone else...
-      //
-      if (Op1I->getOpcode() == Instruction::Sub) {
-        // Swap the two operands of the subexpr...
-        Value *IIOp0 = Op1I->getOperand(0), *IIOp1 = Op1I->getOperand(1);
-        Op1I->setOperand(0, IIOp1);
-        Op1I->setOperand(1, IIOp0);
-
-        // Create the new top level add instruction...
-        return BinaryOperator::CreateAdd(Op0, Op1);
-      }
-
-      // Replace (A - (A & B)) with (A & ~B) if this is the only use of (A&B)...
-      //
-      if (Op1I->getOpcode() == Instruction::And &&
-          (Op1I->getOperand(0) == Op0 || Op1I->getOperand(1) == Op0)) {
-        Value *OtherOp = Op1I->getOperand(Op1I->getOperand(0) == Op0);
-
-        Value *NewNot = Builder->CreateNot(OtherOp, "B.not");
-        return BinaryOperator::CreateAnd(Op0, NewNot);
-      }
-
-      // 0 - (X sdiv C)  -> (X sdiv -C)
-      if (Op1I->getOpcode() == Instruction::SDiv)
-        if (ConstantInt *CSI = dyn_cast<ConstantInt>(Op0))
-          if (CSI->isZero())
-            if (Constant *DivRHS = dyn_cast<Constant>(Op1I->getOperand(1)))
-              return BinaryOperator::CreateSDiv(Op1I->getOperand(0),
-                                          ConstantExpr::getNeg(DivRHS));
-
-      // X - X*C --> X * (1-C)
-      ConstantInt *C2 = 0;
-      if (dyn_castFoldableMul(Op1I, C2) == Op0) {
-        Constant *CP1 = 
-          ConstantExpr::getSub(ConstantInt::get(I.getType(), 1),
-                                             C2);
-        return BinaryOperator::CreateMul(Op0, CP1);
-      }
-    }
-  }
-
-  if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) {
-    if (Op0I->getOpcode() == Instruction::Add) {
-      if (Op0I->getOperand(0) == Op1)             // (Y+X)-Y == X
-        return ReplaceInstUsesWith(I, Op0I->getOperand(1));
-      else if (Op0I->getOperand(1) == Op1)        // (X+Y)-Y == X
-        return ReplaceInstUsesWith(I, Op0I->getOperand(0));
-    } else if (Op0I->getOpcode() == Instruction::Sub) {
-      if (Op0I->getOperand(0) == Op1)             // (X-Y)-X == -Y
-        return BinaryOperator::CreateNeg(Op0I->getOperand(1),
-                                         I.getName());
-    }
-  }
-
-  ConstantInt *C1;
-  if (Value *X = dyn_castFoldableMul(Op0, C1)) {
-    if (X == Op1)  // X*C - X --> X * (C-1)
-      return BinaryOperator::CreateMul(Op1, SubOne(C1));
-
-    ConstantInt *C2;   // X*C1 - X*C2 -> X * (C1-C2)
-    if (X == dyn_castFoldableMul(Op1, C2))
-      return BinaryOperator::CreateMul(X, ConstantExpr::getSub(C1, C2));
-  }
-  
-  // Optimize pointer differences into the same array into a size.  Consider:
-  //  &A[10] - &A[0]: we should compile this to "10".
-  if (TD) {
-    Value *LHSOp, *RHSOp;
-    if (match(Op0, m_PtrToInt(m_Value(LHSOp))) &&
-        match(Op1, m_PtrToInt(m_Value(RHSOp))))
-      if (Value *Res = OptimizePointerDifference(LHSOp, RHSOp, I.getType()))
-        return ReplaceInstUsesWith(I, Res);
-    
-    // trunc(p)-trunc(q) -> trunc(p-q)
-    if (match(Op0, m_Trunc(m_PtrToInt(m_Value(LHSOp)))) &&
-        match(Op1, m_Trunc(m_PtrToInt(m_Value(RHSOp)))))
-      if (Value *Res = OptimizePointerDifference(LHSOp, RHSOp, I.getType()))
-        return ReplaceInstUsesWith(I, Res);
-  }
-  
-  return 0;
-}
-
-Instruction *InstCombiner::visitFSub(BinaryOperator &I) {
-  Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
-  // If this is a 'B = x-(-A)', change to B = x+A...
-  if (Value *V = dyn_castFNegVal(Op1))
-    return BinaryOperator::CreateFAdd(Op0, V);
-
-  if (BinaryOperator *Op1I = dyn_cast<BinaryOperator>(Op1)) {
-    if (Op1I->getOpcode() == Instruction::FAdd) {
-      if (Op1I->getOperand(0) == Op0)              // X-(X+Y) == -Y
-        return BinaryOperator::CreateFNeg(Op1I->getOperand(1),
-                                          I.getName());
-      else if (Op1I->getOperand(1) == Op0)         // X-(Y+X) == -Y
-        return BinaryOperator::CreateFNeg(Op1I->getOperand(0),
-                                          I.getName());
-    }
-  }
-
-  return 0;
-}
-
-/// isSignBitCheck - Given an exploded icmp instruction, return true if the
-/// comparison only checks the sign bit.  If it only checks the sign bit, set
-/// TrueIfSigned if the result of the comparison is true when the input value is
-/// signed.
-static bool isSignBitCheck(ICmpInst::Predicate pred, ConstantInt *RHS,
-                           bool &TrueIfSigned) {
-  switch (pred) {
-  case ICmpInst::ICMP_SLT:   // True if LHS s< 0
-    TrueIfSigned = true;
-    return RHS->isZero();
-  case ICmpInst::ICMP_SLE:   // True if LHS s<= RHS and RHS == -1
-    TrueIfSigned = true;
-    return RHS->isAllOnesValue();
-  case ICmpInst::ICMP_SGT:   // True if LHS s> -1
-    TrueIfSigned = false;
-    return RHS->isAllOnesValue();
-  case ICmpInst::ICMP_UGT:
-    // True if LHS u> RHS and RHS == high-bit-mask - 1
-    TrueIfSigned = true;
-    return RHS->getValue() ==
-      APInt::getSignedMaxValue(RHS->getType()->getPrimitiveSizeInBits());
-  case ICmpInst::ICMP_UGE: 
-    // True if LHS u>= RHS and RHS == high-bit-mask (2^7, 2^15, 2^31, etc)
-    TrueIfSigned = true;
-    return RHS->getValue().isSignBit();
-  default:
-    return false;
-  }
-}
-
-Instruction *InstCombiner::visitMul(BinaryOperator &I) {
-  bool Changed = SimplifyCommutative(I);
-  Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
-  if (isa<UndefValue>(Op1))              // undef * X -> 0
-    return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
-
-  // Simplify mul instructions with a constant RHS.
-  if (Constant *Op1C = dyn_cast<Constant>(Op1)) {
-    if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1C)) {
-
-      // ((X << C1)*C2) == (X * (C2 << C1))
-      if (BinaryOperator *SI = dyn_cast<BinaryOperator>(Op0))
-        if (SI->getOpcode() == Instruction::Shl)
-          if (Constant *ShOp = dyn_cast<Constant>(SI->getOperand(1)))
-            return BinaryOperator::CreateMul(SI->getOperand(0),
-                                        ConstantExpr::getShl(CI, ShOp));
-
-      if (CI->isZero())
-        return ReplaceInstUsesWith(I, Op1C);  // X * 0  == 0
-      if (CI->equalsInt(1))                  // X * 1  == X
-        return ReplaceInstUsesWith(I, Op0);
-      if (CI->isAllOnesValue())              // X * -1 == 0 - X
-        return BinaryOperator::CreateNeg(Op0, I.getName());
-
-      const APInt& Val = cast<ConstantInt>(CI)->getValue();
-      if (Val.isPowerOf2()) {          // Replace X*(2^C) with X << C
-        return BinaryOperator::CreateShl(Op0,
-                 ConstantInt::get(Op0->getType(), Val.logBase2()));
-      }
-    } else if (isa<VectorType>(Op1C->getType())) {
-      if (Op1C->isNullValue())
-        return ReplaceInstUsesWith(I, Op1C);
-
-      if (ConstantVector *Op1V = dyn_cast<ConstantVector>(Op1C)) {
-        if (Op1V->isAllOnesValue())              // X * -1 == 0 - X
-          return BinaryOperator::CreateNeg(Op0, I.getName());
-
-        // As above, vector X*splat(1.0) -> X in all defined cases.
-        if (Constant *Splat = Op1V->getSplatValue()) {
-          if (ConstantInt *CI = dyn_cast<ConstantInt>(Splat))
-            if (CI->equalsInt(1))
-              return ReplaceInstUsesWith(I, Op0);
-        }
-      }
-    }
-    
-    if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0))
-      if (Op0I->getOpcode() == Instruction::Add && Op0I->hasOneUse() &&
-          isa<ConstantInt>(Op0I->getOperand(1)) && isa<ConstantInt>(Op1C)) {
-        // Canonicalize (X+C1)*C2 -> X*C2+C1*C2.
-        Value *Add = Builder->CreateMul(Op0I->getOperand(0), Op1C, "tmp");
-        Value *C1C2 = Builder->CreateMul(Op1C, Op0I->getOperand(1));
-        return BinaryOperator::CreateAdd(Add, C1C2);
-        
-      }
-
-    // Try to fold constant mul into select arguments.
-    if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
-      if (Instruction *R = FoldOpIntoSelect(I, SI, this))
-        return R;
-
-    if (isa<PHINode>(Op0))
-      if (Instruction *NV = FoldOpIntoPhi(I))
-        return NV;
-  }
-
-  if (Value *Op0v = dyn_castNegVal(Op0))     // -X * -Y = X*Y
-    if (Value *Op1v = dyn_castNegVal(Op1))
-      return BinaryOperator::CreateMul(Op0v, Op1v);
-
-  // (X / Y) *  Y = X - (X % Y)
-  // (X / Y) * -Y = (X % Y) - X
-  {
-    Value *Op1C = Op1;
-    BinaryOperator *BO = dyn_cast<BinaryOperator>(Op0);
-    if (!BO ||
-        (BO->getOpcode() != Instruction::UDiv && 
-         BO->getOpcode() != Instruction::SDiv)) {
-      Op1C = Op0;
-      BO = dyn_cast<BinaryOperator>(Op1);
-    }
-    Value *Neg = dyn_castNegVal(Op1C);
-    if (BO && BO->hasOneUse() &&
-        (BO->getOperand(1) == Op1C || BO->getOperand(1) == Neg) &&
-        (BO->getOpcode() == Instruction::UDiv ||
-         BO->getOpcode() == Instruction::SDiv)) {
-      Value *Op0BO = BO->getOperand(0), *Op1BO = BO->getOperand(1);
-
-      // If the division is exact, X % Y is zero.
-      if (SDivOperator *SDiv = dyn_cast<SDivOperator>(BO))
-        if (SDiv->isExact()) {
-          if (Op1BO == Op1C)
-            return ReplaceInstUsesWith(I, Op0BO);
-          return BinaryOperator::CreateNeg(Op0BO);
-        }
-
-      Value *Rem;
-      if (BO->getOpcode() == Instruction::UDiv)
-        Rem = Builder->CreateURem(Op0BO, Op1BO);
-      else
-        Rem = Builder->CreateSRem(Op0BO, Op1BO);
-      Rem->takeName(BO);
-
-      if (Op1BO == Op1C)
-        return BinaryOperator::CreateSub(Op0BO, Rem);
-      return BinaryOperator::CreateSub(Rem, Op0BO);
-    }
-  }
-
-  /// i1 mul -> i1 and.
-  if (I.getType() == Type::getInt1Ty(*Context))
-    return BinaryOperator::CreateAnd(Op0, Op1);
-
-  // X*(1 << Y) --> X << Y
-  // (1 << Y)*X --> X << Y
-  {
-    Value *Y;
-    if (match(Op0, m_Shl(m_One(), m_Value(Y))))
-      return BinaryOperator::CreateShl(Op1, Y);
-    if (match(Op1, m_Shl(m_One(), m_Value(Y))))
-      return BinaryOperator::CreateShl(Op0, Y);
-  }
-  
-  // If one of the operands of the multiply is a cast from a boolean value, then
-  // we know the bool is either zero or one, so this is a 'masking' multiply.
-  //   X * Y (where Y is 0 or 1) -> X & (0-Y)
-  if (!isa<VectorType>(I.getType())) {
-    // -2 is "-1 << 1" so it is all bits set except the low one.
-    APInt Negative2(I.getType()->getPrimitiveSizeInBits(), (uint64_t)-2, true);
-    
-    Value *BoolCast = 0, *OtherOp = 0;
-    if (MaskedValueIsZero(Op0, Negative2))
-      BoolCast = Op0, OtherOp = Op1;
-    else if (MaskedValueIsZero(Op1, Negative2))
-      BoolCast = Op1, OtherOp = Op0;
-
-    if (BoolCast) {
-      Value *V = Builder->CreateSub(Constant::getNullValue(I.getType()),
-                                    BoolCast, "tmp");
-      return BinaryOperator::CreateAnd(V, OtherOp);
-    }
-  }
-
-  return Changed ? &I : 0;
-}
-
-Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
-  bool Changed = SimplifyCommutative(I);
-  Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
-  // Simplify mul instructions with a constant RHS...
-  if (Constant *Op1C = dyn_cast<Constant>(Op1)) {
-    if (ConstantFP *Op1F = dyn_cast<ConstantFP>(Op1C)) {
-      // "In IEEE floating point, x*1 is not equivalent to x for nans.  However,
-      // ANSI says we can drop signals, so we can do this anyway." (from GCC)
-      if (Op1F->isExactlyValue(1.0))
-        return ReplaceInstUsesWith(I, Op0);  // Eliminate 'mul double %X, 1.0'
-    } else if (isa<VectorType>(Op1C->getType())) {
-      if (ConstantVector *Op1V = dyn_cast<ConstantVector>(Op1C)) {
-        // As above, vector X*splat(1.0) -> X in all defined cases.
-        if (Constant *Splat = Op1V->getSplatValue()) {
-          if (ConstantFP *F = dyn_cast<ConstantFP>(Splat))
-            if (F->isExactlyValue(1.0))
-              return ReplaceInstUsesWith(I, Op0);
-        }
-      }
-    }
-
-    // Try to fold constant mul into select arguments.
-    if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
-      if (Instruction *R = FoldOpIntoSelect(I, SI, this))
-        return R;
-
-    if (isa<PHINode>(Op0))
-      if (Instruction *NV = FoldOpIntoPhi(I))
-        return NV;
-  }
-
-  if (Value *Op0v = dyn_castFNegVal(Op0))     // -X * -Y = X*Y
-    if (Value *Op1v = dyn_castFNegVal(Op1))
-      return BinaryOperator::CreateFMul(Op0v, Op1v);
-
-  return Changed ? &I : 0;
-}
-
-/// SimplifyDivRemOfSelect - Try to fold a divide or remainder of a select
-/// instruction.
-bool InstCombiner::SimplifyDivRemOfSelect(BinaryOperator &I) {
-  SelectInst *SI = cast<SelectInst>(I.getOperand(1));
-  
-  // div/rem X, (Cond ? 0 : Y) -> div/rem X, Y
-  int NonNullOperand = -1;
-  if (Constant *ST = dyn_cast<Constant>(SI->getOperand(1)))
-    if (ST->isNullValue())
-      NonNullOperand = 2;
-  // div/rem X, (Cond ? Y : 0) -> div/rem X, Y
-  if (Constant *ST = dyn_cast<Constant>(SI->getOperand(2)))
-    if (ST->isNullValue())
-      NonNullOperand = 1;
-  
-  if (NonNullOperand == -1)
-    return false;
-  
-  Value *SelectCond = SI->getOperand(0);
-  
-  // Change the div/rem to use 'Y' instead of the select.
-  I.setOperand(1, SI->getOperand(NonNullOperand));
-  
-  // Okay, we know we replace the operand of the div/rem with 'Y' with no
-  // problem.  However, the select, or the condition of the select may have
-  // multiple uses.  Based on our knowledge that the operand must be non-zero,
-  // propagate the known value for the select into other uses of it, and
-  // propagate a known value of the condition into its other users.
-  
-  // If the select and condition only have a single use, don't bother with this,
-  // early exit.
-  if (SI->use_empty() && SelectCond->hasOneUse())
-    return true;
-  
-  // Scan the current block backward, looking for other uses of SI.
-  BasicBlock::iterator BBI = &I, BBFront = I.getParent()->begin();
-  
-  while (BBI != BBFront) {
-    --BBI;
-    // If we found a call to a function, we can't assume it will return, so
-    // information from below it cannot be propagated above it.
-    if (isa<CallInst>(BBI) && !isa<IntrinsicInst>(BBI))
-      break;
-    
-    // Replace uses of the select or its condition with the known values.
-    for (Instruction::op_iterator I = BBI->op_begin(), E = BBI->op_end();
-         I != E; ++I) {
-      if (*I == SI) {
-        *I = SI->getOperand(NonNullOperand);
-        Worklist.Add(BBI);
-      } else if (*I == SelectCond) {
-        *I = NonNullOperand == 1 ? ConstantInt::getTrue(*Context) :
-                                   ConstantInt::getFalse(*Context);
-        Worklist.Add(BBI);
-      }
-    }
-    
-    // If we past the instruction, quit looking for it.
-    if (&*BBI == SI)
-      SI = 0;
-    if (&*BBI == SelectCond)
-      SelectCond = 0;
-    
-    // If we ran out of things to eliminate, break out of the loop.
-    if (SelectCond == 0 && SI == 0)
-      break;
-    
-  }
-  return true;
-}
-
-
-/// This function implements the transforms on div instructions that work
-/// regardless of the kind of div instruction it is (udiv, sdiv, or fdiv). It is
-/// used by the visitors to those instructions.
-/// @brief Transforms common to all three div instructions
-Instruction *InstCombiner::commonDivTransforms(BinaryOperator &I) {
-  Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
-  // undef / X -> 0        for integer.
-  // undef / X -> undef    for FP (the undef could be a snan).
-  if (isa<UndefValue>(Op0)) {
-    if (Op0->getType()->isFPOrFPVector())
-      return ReplaceInstUsesWith(I, Op0);
-    return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
-  }
-
-  // X / undef -> undef
-  if (isa<UndefValue>(Op1))
-    return ReplaceInstUsesWith(I, Op1);
-
-  return 0;
-}
-
-/// This function implements the transforms common to both integer division
-/// instructions (udiv and sdiv). It is called by the visitors to those integer
-/// division instructions.
-/// @brief Common integer divide transforms
-Instruction *InstCombiner::commonIDivTransforms(BinaryOperator &I) {
-  Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
-  // (sdiv X, X) --> 1     (udiv X, X) --> 1
-  if (Op0 == Op1) {
-    if (const VectorType *Ty = dyn_cast<VectorType>(I.getType())) {
-      Constant *CI = ConstantInt::get(Ty->getElementType(), 1);
-      std::vector<Constant*> Elts(Ty->getNumElements(), CI);
-      return ReplaceInstUsesWith(I, ConstantVector::get(Elts));
-    }
-
-    Constant *CI = ConstantInt::get(I.getType(), 1);
-    return ReplaceInstUsesWith(I, CI);
-  }
-  
-  if (Instruction *Common = commonDivTransforms(I))
-    return Common;
-  
-  // Handle cases involving: [su]div X, (select Cond, Y, Z)
-  // This does not apply for fdiv.
-  if (isa<SelectInst>(Op1) && SimplifyDivRemOfSelect(I))
-    return &I;
-
-  if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
-    // div X, 1 == X
-    if (RHS->equalsInt(1))
-      return ReplaceInstUsesWith(I, Op0);
-
-    // (X / C1) / C2  -> X / (C1*C2)
-    if (Instruction *LHS = dyn_cast<Instruction>(Op0))
-      if (Instruction::BinaryOps(LHS->getOpcode()) == I.getOpcode())
-        if (ConstantInt *LHSRHS = dyn_cast<ConstantInt>(LHS->getOperand(1))) {
-          if (MultiplyOverflows(RHS, LHSRHS,
-                                I.getOpcode()==Instruction::SDiv))
-            return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
-          else 
-            return BinaryOperator::Create(I.getOpcode(), LHS->getOperand(0),
-                                      ConstantExpr::getMul(RHS, LHSRHS));
-        }
-
-    if (!RHS->isZero()) { // avoid X udiv 0
-      if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
-        if (Instruction *R = FoldOpIntoSelect(I, SI, this))
-          return R;
-      if (isa<PHINode>(Op0))
-        if (Instruction *NV = FoldOpIntoPhi(I))
-          return NV;
-    }
-  }
-
-  // 0 / X == 0, we don't need to preserve faults!
-  if (ConstantInt *LHS = dyn_cast<ConstantInt>(Op0))
-    if (LHS->equalsInt(0))
-      return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
-
-  // It can't be division by zero, hence it must be division by one.
-  if (I.getType() == Type::getInt1Ty(*Context))
-    return ReplaceInstUsesWith(I, Op0);
-
-  if (ConstantVector *Op1V = dyn_cast<ConstantVector>(Op1)) {
-    if (ConstantInt *X = cast_or_null<ConstantInt>(Op1V->getSplatValue()))
-      // div X, 1 == X
-      if (X->isOne())
-        return ReplaceInstUsesWith(I, Op0);
-  }
-
-  return 0;
-}
-
-Instruction *InstCombiner::visitUDiv(BinaryOperator &I) {
-  Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
-  // Handle the integer div common cases
-  if (Instruction *Common = commonIDivTransforms(I))
-    return Common;
-
-  if (ConstantInt *C = dyn_cast<ConstantInt>(Op1)) {
-    // X udiv C^2 -> X >> C
-    // Check to see if this is an unsigned division with an exact power of 2,
-    // if so, convert to a right shift.
-    if (C->getValue().isPowerOf2())  // 0 not included in isPowerOf2
-      return BinaryOperator::CreateLShr(Op0, 
-            ConstantInt::get(Op0->getType(), C->getValue().logBase2()));
-
-    // X udiv C, where C >= signbit
-    if (C->getValue().isNegative()) {
-      Value *IC = Builder->CreateICmpULT( Op0, C);
-      return SelectInst::Create(IC, Constant::getNullValue(I.getType()),
-                                ConstantInt::get(I.getType(), 1));
-    }
-  }
-
-  // X udiv (C1 << N), where C1 is "1<<C2"  -->  X >> (N+C2)
-  if (BinaryOperator *RHSI = dyn_cast<BinaryOperator>(I.getOperand(1))) {
-    if (RHSI->getOpcode() == Instruction::Shl &&
-        isa<ConstantInt>(RHSI->getOperand(0))) {
-      const APInt& C1 = cast<ConstantInt>(RHSI->getOperand(0))->getValue();
-      if (C1.isPowerOf2()) {
-        Value *N = RHSI->getOperand(1);
-        const Type *NTy = N->getType();
-        if (uint32_t C2 = C1.logBase2())
-          N = Builder->CreateAdd(N, ConstantInt::get(NTy, C2), "tmp");
-        return BinaryOperator::CreateLShr(Op0, N);
-      }
-    }
-  }
-  
-  // udiv X, (Select Cond, C1, C2) --> Select Cond, (shr X, C1), (shr X, C2)
-  // where C1&C2 are powers of two.
-  if (SelectInst *SI = dyn_cast<SelectInst>(Op1)) 
-    if (ConstantInt *STO = dyn_cast<ConstantInt>(SI->getOperand(1)))
-      if (ConstantInt *SFO = dyn_cast<ConstantInt>(SI->getOperand(2)))  {
-        const APInt &TVA = STO->getValue(), &FVA = SFO->getValue();
-        if (TVA.isPowerOf2() && FVA.isPowerOf2()) {
-          // Compute the shift amounts
-          uint32_t TSA = TVA.logBase2(), FSA = FVA.logBase2();
-          // Construct the "on true" case of the select
-          Constant *TC = ConstantInt::get(Op0->getType(), TSA);
-          Value *TSI = Builder->CreateLShr(Op0, TC, SI->getName()+".t");
-  
-          // Construct the "on false" case of the select
-          Constant *FC = ConstantInt::get(Op0->getType(), FSA); 
-          Value *FSI = Builder->CreateLShr(Op0, FC, SI->getName()+".f");
-
-          // construct the select instruction and return it.
-          return SelectInst::Create(SI->getOperand(0), TSI, FSI, SI->getName());
-        }
-      }
-  return 0;
-}
-
-Instruction *InstCombiner::visitSDiv(BinaryOperator &I) {
-  Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
-  // Handle the integer div common cases
-  if (Instruction *Common = commonIDivTransforms(I))
-    return Common;
-
-  if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
-    // sdiv X, -1 == -X
-    if (RHS->isAllOnesValue())
-      return BinaryOperator::CreateNeg(Op0);
-
-    // sdiv X, C  -->  ashr X, log2(C)
-    if (cast<SDivOperator>(&I)->isExact() &&
-        RHS->getValue().isNonNegative() &&
-        RHS->getValue().isPowerOf2()) {
-      Value *ShAmt = llvm::ConstantInt::get(RHS->getType(),
-                                            RHS->getValue().exactLogBase2());
-      return BinaryOperator::CreateAShr(Op0, ShAmt, I.getName());
-    }
-
-    // -X/C  -->  X/-C  provided the negation doesn't overflow.
-    if (SubOperator *Sub = dyn_cast<SubOperator>(Op0))
-      if (isa<Constant>(Sub->getOperand(0)) &&
-          cast<Constant>(Sub->getOperand(0))->isNullValue() &&
-          Sub->hasNoSignedWrap())
-        return BinaryOperator::CreateSDiv(Sub->getOperand(1),
-                                          ConstantExpr::getNeg(RHS));
-  }
-
-  // If the sign bits of both operands are zero (i.e. we can prove they are
-  // unsigned inputs), turn this into a udiv.
-  if (I.getType()->isInteger()) {
-    APInt Mask(APInt::getSignBit(I.getType()->getPrimitiveSizeInBits()));
-    if (MaskedValueIsZero(Op0, Mask)) {
-      if (MaskedValueIsZero(Op1, Mask)) {
-        // X sdiv Y -> X udiv Y, iff X and Y don't have sign bit set
-        return BinaryOperator::CreateUDiv(Op0, Op1, I.getName());
-      }
-      ConstantInt *ShiftedInt;
-      if (match(Op1, m_Shl(m_ConstantInt(ShiftedInt), m_Value())) &&
-          ShiftedInt->getValue().isPowerOf2()) {
-        // X sdiv (1 << Y) -> X udiv (1 << Y) ( -> X u>> Y)
-        // Safe because the only negative value (1 << Y) can take on is
-        // INT_MIN, and X sdiv INT_MIN == X udiv INT_MIN == 0 if X doesn't have
-        // the sign bit set.
-        return BinaryOperator::CreateUDiv(Op0, Op1, I.getName());
-      }
-    }
-  }
-  
-  return 0;
-}
-
-Instruction *InstCombiner::visitFDiv(BinaryOperator &I) {
-  return commonDivTransforms(I);
-}
-
-/// This function implements the transforms on rem instructions that work
-/// regardless of the kind of rem instruction it is (urem, srem, or frem). It 
-/// is used by the visitors to those instructions.
-/// @brief Transforms common to all three rem instructions
-Instruction *InstCombiner::commonRemTransforms(BinaryOperator &I) {
-  Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
-  if (isa<UndefValue>(Op0)) {             // undef % X -> 0
-    if (I.getType()->isFPOrFPVector())
-      return ReplaceInstUsesWith(I, Op0);  // X % undef -> undef (could be SNaN)
-    return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
-  }
-  if (isa<UndefValue>(Op1))
-    return ReplaceInstUsesWith(I, Op1);  // X % undef -> undef
-
-  // Handle cases involving: rem X, (select Cond, Y, Z)
-  if (isa<SelectInst>(Op1) && SimplifyDivRemOfSelect(I))
-    return &I;
-
-  return 0;
-}
-
-/// This function implements the transforms common to both integer remainder
-/// instructions (urem and srem). It is called by the visitors to those integer
-/// remainder instructions.
-/// @brief Common integer remainder transforms
-Instruction *InstCombiner::commonIRemTransforms(BinaryOperator &I) {
-  Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
-  if (Instruction *common = commonRemTransforms(I))
-    return common;
-
-  // 0 % X == 0 for integer, we don't need to preserve faults!
-  if (Constant *LHS = dyn_cast<Constant>(Op0))
-    if (LHS->isNullValue())
-      return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
-
-  if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
-    // X % 0 == undef, we don't need to preserve faults!
-    if (RHS->equalsInt(0))
-      return ReplaceInstUsesWith(I, UndefValue::get(I.getType()));
-    
-    if (RHS->equalsInt(1))  // X % 1 == 0
-      return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
-
-    if (Instruction *Op0I = dyn_cast<Instruction>(Op0)) {
-      if (SelectInst *SI = dyn_cast<SelectInst>(Op0I)) {
-        if (Instruction *R = FoldOpIntoSelect(I, SI, this))
-          return R;
-      } else if (isa<PHINode>(Op0I)) {
-        if (Instruction *NV = FoldOpIntoPhi(I))
-          return NV;
-      }
-
-      // See if we can fold away this rem instruction.
-      if (SimplifyDemandedInstructionBits(I))
-        return &I;
-    }
-  }
-
-  return 0;
-}
-
-Instruction *InstCombiner::visitURem(BinaryOperator &I) {
-  Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
-  if (Instruction *common = commonIRemTransforms(I))
-    return common;
-  
-  if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
-    // X urem C^2 -> X and C
-    // Check to see if this is an unsigned remainder with an exact power of 2,
-    // if so, convert to a bitwise and.
-    if (ConstantInt *C = dyn_cast<ConstantInt>(RHS))
-      if (C->getValue().isPowerOf2())
-        return BinaryOperator::CreateAnd(Op0, SubOne(C));
-  }
-
-  if (Instruction *RHSI = dyn_cast<Instruction>(I.getOperand(1))) {
-    // Turn A % (C << N), where C is 2^k, into A & ((C << N)-1)  
-    if (RHSI->getOpcode() == Instruction::Shl &&
-        isa<ConstantInt>(RHSI->getOperand(0))) {
-      if (cast<ConstantInt>(RHSI->getOperand(0))->getValue().isPowerOf2()) {
-        Constant *N1 = Constant::getAllOnesValue(I.getType());
-        Value *Add = Builder->CreateAdd(RHSI, N1, "tmp");
-        return BinaryOperator::CreateAnd(Op0, Add);
-      }
-    }
-  }
-
-  // urem X, (select Cond, 2^C1, 2^C2) --> select Cond, (and X, C1), (and X, C2)
-  // where C1&C2 are powers of two.
-  if (SelectInst *SI = dyn_cast<SelectInst>(Op1)) {
-    if (ConstantInt *STO = dyn_cast<ConstantInt>(SI->getOperand(1)))
-      if (ConstantInt *SFO = dyn_cast<ConstantInt>(SI->getOperand(2))) {
-        // STO == 0 and SFO == 0 handled above.
-        if ((STO->getValue().isPowerOf2()) && 
-            (SFO->getValue().isPowerOf2())) {
-          Value *TrueAnd = Builder->CreateAnd(Op0, SubOne(STO),
-                                              SI->getName()+".t");
-          Value *FalseAnd = Builder->CreateAnd(Op0, SubOne(SFO),
-                                               SI->getName()+".f");
-          return SelectInst::Create(SI->getOperand(0), TrueAnd, FalseAnd);
-        }
-      }
-  }
-  
-  return 0;
-}
-
-Instruction *InstCombiner::visitSRem(BinaryOperator &I) {
-  Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
-  // Handle the integer rem common cases
-  if (Instruction *Common = commonIRemTransforms(I))
-    return Common;
-  
-  if (Value *RHSNeg = dyn_castNegVal(Op1))
-    if (!isa<Constant>(RHSNeg) ||
-        (isa<ConstantInt>(RHSNeg) &&
-         cast<ConstantInt>(RHSNeg)->getValue().isStrictlyPositive())) {
-      // X % -Y -> X % Y
-      Worklist.AddValue(I.getOperand(1));
-      I.setOperand(1, RHSNeg);
-      return &I;
-    }
-
-  // If the sign bits of both operands are zero (i.e. we can prove they are
-  // unsigned inputs), turn this into a urem.
-  if (I.getType()->isInteger()) {
-    APInt Mask(APInt::getSignBit(I.getType()->getPrimitiveSizeInBits()));
-    if (MaskedValueIsZero(Op1, Mask) && MaskedValueIsZero(Op0, Mask)) {
-      // X srem Y -> X urem Y, iff X and Y don't have sign bit set
-      return BinaryOperator::CreateURem(Op0, Op1, I.getName());
-    }
-  }
-
-  // If it's a constant vector, flip any negative values positive.
-  if (ConstantVector *RHSV = dyn_cast<ConstantVector>(Op1)) {
-    unsigned VWidth = RHSV->getNumOperands();
-
-    bool hasNegative = false;
-    for (unsigned i = 0; !hasNegative && i != VWidth; ++i)
-      if (ConstantInt *RHS = dyn_cast<ConstantInt>(RHSV->getOperand(i)))
-        if (RHS->getValue().isNegative())
-          hasNegative = true;
-
-    if (hasNegative) {
-      std::vector<Constant *> Elts(VWidth);
-      for (unsigned i = 0; i != VWidth; ++i) {
-        if (ConstantInt *RHS = dyn_cast<ConstantInt>(RHSV->getOperand(i))) {
-          if (RHS->getValue().isNegative())
-            Elts[i] = cast<ConstantInt>(ConstantExpr::getNeg(RHS));
-          else
-            Elts[i] = RHS;
-        }
-      }
-
-      Constant *NewRHSV = ConstantVector::get(Elts);
-      if (NewRHSV != RHSV) {
-        Worklist.AddValue(I.getOperand(1));
-        I.setOperand(1, NewRHSV);
-        return &I;
-      }
-    }
-  }
-
-  return 0;
-}
-
-Instruction *InstCombiner::visitFRem(BinaryOperator &I) {
-  return commonRemTransforms(I);
-}
-
-// isOneBitSet - Return true if there is exactly one bit set in the specified
-// constant.
-static bool isOneBitSet(const ConstantInt *CI) {
-  return CI->getValue().isPowerOf2();
-}
-
-// isHighOnes - Return true if the constant is of the form 1+0+.
-// This is the same as lowones(~X).
-static bool isHighOnes(const ConstantInt *CI) {
-  return (~CI->getValue() + 1).isPowerOf2();
-}
-
-/// getICmpCode - Encode a icmp predicate into a three bit mask.  These bits
-/// are carefully arranged to allow folding of expressions such as:
-///
-///      (A < B) | (A > B) --> (A != B)
-///
-/// Note that this is only valid if the first and second predicates have the
-/// same sign. Is illegal to do: (A u< B) | (A s> B) 
-///
-/// Three bits are used to represent the condition, as follows:
-///   0  A > B
-///   1  A == B
-///   2  A < B
-///
-/// <=>  Value  Definition
-/// 000     0   Always false
-/// 001     1   A >  B
-/// 010     2   A == B
-/// 011     3   A >= B
-/// 100     4   A <  B
-/// 101     5   A != B
-/// 110     6   A <= B
-/// 111     7   Always true
-///  
-static unsigned getICmpCode(const ICmpInst *ICI) {
-  switch (ICI->getPredicate()) {
-    // False -> 0
-  case ICmpInst::ICMP_UGT: return 1;  // 001
-  case ICmpInst::ICMP_SGT: return 1;  // 001
-  case ICmpInst::ICMP_EQ:  return 2;  // 010
-  case ICmpInst::ICMP_UGE: return 3;  // 011
-  case ICmpInst::ICMP_SGE: return 3;  // 011
-  case ICmpInst::ICMP_ULT: return 4;  // 100
-  case ICmpInst::ICMP_SLT: return 4;  // 100
-  case ICmpInst::ICMP_NE:  return 5;  // 101
-  case ICmpInst::ICMP_ULE: return 6;  // 110
-  case ICmpInst::ICMP_SLE: return 6;  // 110
-    // True -> 7
-  default:
-    llvm_unreachable("Invalid ICmp predicate!");
-    return 0;
-  }
-}
-
-/// getFCmpCode - Similar to getICmpCode but for FCmpInst. This encodes a fcmp
-/// predicate into a three bit mask. It also returns whether it is an ordered
-/// predicate by reference.
-static unsigned getFCmpCode(FCmpInst::Predicate CC, bool &isOrdered) {
-  isOrdered = false;
-  switch (CC) {
-  case FCmpInst::FCMP_ORD: isOrdered = true; return 0;  // 000
-  case FCmpInst::FCMP_UNO:                   return 0;  // 000
-  case FCmpInst::FCMP_OGT: isOrdered = true; return 1;  // 001
-  case FCmpInst::FCMP_UGT:                   return 1;  // 001
-  case FCmpInst::FCMP_OEQ: isOrdered = true; return 2;  // 010
-  case FCmpInst::FCMP_UEQ:                   return 2;  // 010
-  case FCmpInst::FCMP_OGE: isOrdered = true; return 3;  // 011
-  case FCmpInst::FCMP_UGE:                   return 3;  // 011
-  case FCmpInst::FCMP_OLT: isOrdered = true; return 4;  // 100
-  case FCmpInst::FCMP_ULT:                   return 4;  // 100
-  case FCmpInst::FCMP_ONE: isOrdered = true; return 5;  // 101
-  case FCmpInst::FCMP_UNE:                   return 5;  // 101
-  case FCmpInst::FCMP_OLE: isOrdered = true; return 6;  // 110
-  case FCmpInst::FCMP_ULE:                   return 6;  // 110
-    // True -> 7
-  default:
-    // Not expecting FCMP_FALSE and FCMP_TRUE;
-    llvm_unreachable("Unexpected FCmp predicate!");
-    return 0;
-  }
-}
-
-/// getICmpValue - This is the complement of getICmpCode, which turns an
-/// opcode and two operands into either a constant true or false, or a brand 
-/// new ICmp instruction. The sign is passed in to determine which kind
-/// of predicate to use in the new icmp instruction.
-static Value *getICmpValue(bool sign, unsigned code, Value *LHS, Value *RHS,
-                           LLVMContext *Context) {
-  switch (code) {
-  default: llvm_unreachable("Illegal ICmp code!");
-  case  0: return ConstantInt::getFalse(*Context);
-  case  1: 
-    if (sign)
-      return new ICmpInst(ICmpInst::ICMP_SGT, LHS, RHS);
-    else
-      return new ICmpInst(ICmpInst::ICMP_UGT, LHS, RHS);
-  case  2: return new ICmpInst(ICmpInst::ICMP_EQ,  LHS, RHS);
-  case  3: 
-    if (sign)
-      return new ICmpInst(ICmpInst::ICMP_SGE, LHS, RHS);
-    else
-      return new ICmpInst(ICmpInst::ICMP_UGE, LHS, RHS);
-  case  4: 
-    if (sign)
-      return new ICmpInst(ICmpInst::ICMP_SLT, LHS, RHS);
-    else
-      return new ICmpInst(ICmpInst::ICMP_ULT, LHS, RHS);
-  case  5: return new ICmpInst(ICmpInst::ICMP_NE,  LHS, RHS);
-  case  6: 
-    if (sign)
-      return new ICmpInst(ICmpInst::ICMP_SLE, LHS, RHS);
-    else
-      return new ICmpInst(ICmpInst::ICMP_ULE, LHS, RHS);
-  case  7: return ConstantInt::getTrue(*Context);
-  }
-}
-
-/// getFCmpValue - This is the complement of getFCmpCode, which turns an
-/// opcode and two operands into either a FCmp instruction. isordered is passed
-/// in to determine which kind of predicate to use in the new fcmp instruction.
-static Value *getFCmpValue(bool isordered, unsigned code,
-                           Value *LHS, Value *RHS, LLVMContext *Context) {
-  switch (code) {
-  default: llvm_unreachable("Illegal FCmp code!");
-  case  0:
-    if (isordered)
-      return new FCmpInst(FCmpInst::FCMP_ORD, LHS, RHS);
-    else
-      return new FCmpInst(FCmpInst::FCMP_UNO, LHS, RHS);
-  case  1: 
-    if (isordered)
-      return new FCmpInst(FCmpInst::FCMP_OGT, LHS, RHS);
-    else
-      return new FCmpInst(FCmpInst::FCMP_UGT, LHS, RHS);
-  case  2: 
-    if (isordered)
-      return new FCmpInst(FCmpInst::FCMP_OEQ, LHS, RHS);
-    else
-      return new FCmpInst(FCmpInst::FCMP_UEQ, LHS, RHS);
-  case  3: 
-    if (isordered)
-      return new FCmpInst(FCmpInst::FCMP_OGE, LHS, RHS);
-    else
-      return new FCmpInst(FCmpInst::FCMP_UGE, LHS, RHS);
-  case  4: 
-    if (isordered)
-      return new FCmpInst(FCmpInst::FCMP_OLT, LHS, RHS);
-    else
-      return new FCmpInst(FCmpInst::FCMP_ULT, LHS, RHS);
-  case  5: 
-    if (isordered)
-      return new FCmpInst(FCmpInst::FCMP_ONE, LHS, RHS);
-    else
-      return new FCmpInst(FCmpInst::FCMP_UNE, LHS, RHS);
-  case  6: 
-    if (isordered)
-      return new FCmpInst(FCmpInst::FCMP_OLE, LHS, RHS);
-    else
-      return new FCmpInst(FCmpInst::FCMP_ULE, LHS, RHS);
-  case  7: return ConstantInt::getTrue(*Context);
-  }
-}
-
-/// PredicatesFoldable - Return true if both predicates match sign or if at
-/// least one of them is an equality comparison (which is signless).
-static bool PredicatesFoldable(ICmpInst::Predicate p1, ICmpInst::Predicate p2) {
-  return (CmpInst::isSigned(p1) == CmpInst::isSigned(p2)) ||
-         (CmpInst::isSigned(p1) && ICmpInst::isEquality(p2)) ||
-         (CmpInst::isSigned(p2) && ICmpInst::isEquality(p1));
-}
-
-namespace { 
-// FoldICmpLogical - Implements (icmp1 A, B) & (icmp2 A, B) --> (icmp3 A, B)
-struct FoldICmpLogical {
-  InstCombiner &IC;
-  Value *LHS, *RHS;
-  ICmpInst::Predicate pred;
-  FoldICmpLogical(InstCombiner &ic, ICmpInst *ICI)
-    : IC(ic), LHS(ICI->getOperand(0)), RHS(ICI->getOperand(1)),
-      pred(ICI->getPredicate()) {}
-  bool shouldApply(Value *V) const {
-    if (ICmpInst *ICI = dyn_cast<ICmpInst>(V))
-      if (PredicatesFoldable(pred, ICI->getPredicate()))
-        return ((ICI->getOperand(0) == LHS && ICI->getOperand(1) == RHS) ||
-                (ICI->getOperand(0) == RHS && ICI->getOperand(1) == LHS));
-    return false;
-  }
-  Instruction *apply(Instruction &Log) const {
-    ICmpInst *ICI = cast<ICmpInst>(Log.getOperand(0));
-    if (ICI->getOperand(0) != LHS) {
-      assert(ICI->getOperand(1) == LHS);
-      ICI->swapOperands();  // Swap the LHS and RHS of the ICmp
-    }
-
-    ICmpInst *RHSICI = cast<ICmpInst>(Log.getOperand(1));
-    unsigned LHSCode = getICmpCode(ICI);
-    unsigned RHSCode = getICmpCode(RHSICI);
-    unsigned Code;
-    switch (Log.getOpcode()) {
-    case Instruction::And: Code = LHSCode & RHSCode; break;
-    case Instruction::Or:  Code = LHSCode | RHSCode; break;
-    case Instruction::Xor: Code = LHSCode ^ RHSCode; break;
-    default: llvm_unreachable("Illegal logical opcode!"); return 0;
-    }
-
-    bool isSigned = RHSICI->isSigned() || ICI->isSigned();
-    Value *RV = getICmpValue(isSigned, Code, LHS, RHS, IC.getContext());
-    if (Instruction *I = dyn_cast<Instruction>(RV))
-      return I;
-    // Otherwise, it's a constant boolean value...
-    return IC.ReplaceInstUsesWith(Log, RV);
-  }
-};
-} // end anonymous namespace
-
-// OptAndOp - This handles expressions of the form ((val OP C1) & C2).  Where
-// the Op parameter is 'OP', OpRHS is 'C1', and AndRHS is 'C2'.  Op is
-// guaranteed to be a binary operator.
-Instruction *InstCombiner::OptAndOp(Instruction *Op,
-                                    ConstantInt *OpRHS,
-                                    ConstantInt *AndRHS,
-                                    BinaryOperator &TheAnd) {
-  Value *X = Op->getOperand(0);
-  Constant *Together = 0;
-  if (!Op->isShift())
-    Together = ConstantExpr::getAnd(AndRHS, OpRHS);
-
-  switch (Op->getOpcode()) {
-  case Instruction::Xor:
-    if (Op->hasOneUse()) {
-      // (X ^ C1) & C2 --> (X & C2) ^ (C1&C2)
-      Value *And = Builder->CreateAnd(X, AndRHS);
-      And->takeName(Op);
-      return BinaryOperator::CreateXor(And, Together);
-    }
-    break;
-  case Instruction::Or:
-    if (Together == AndRHS) // (X | C) & C --> C
-      return ReplaceInstUsesWith(TheAnd, AndRHS);
-
-    if (Op->hasOneUse() && Together != OpRHS) {
-      // (X | C1) & C2 --> (X | (C1&C2)) & C2
-      Value *Or = Builder->CreateOr(X, Together);
-      Or->takeName(Op);
-      return BinaryOperator::CreateAnd(Or, AndRHS);
-    }
-    break;
-  case Instruction::Add:
-    if (Op->hasOneUse()) {
-      // Adding a one to a single bit bit-field should be turned into an XOR
-      // of the bit.  First thing to check is to see if this AND is with a
-      // single bit constant.
-      const APInt& AndRHSV = cast<ConstantInt>(AndRHS)->getValue();
-
-      // If there is only one bit set...
-      if (isOneBitSet(cast<ConstantInt>(AndRHS))) {
-        // Ok, at this point, we know that we are masking the result of the
-        // ADD down to exactly one bit.  If the constant we are adding has
-        // no bits set below this bit, then we can eliminate the ADD.
-        const APInt& AddRHS = cast<ConstantInt>(OpRHS)->getValue();
-
-        // Check to see if any bits below the one bit set in AndRHSV are set.
-        if ((AddRHS & (AndRHSV-1)) == 0) {
-          // If not, the only thing that can effect the output of the AND is
-          // the bit specified by AndRHSV.  If that bit is set, the effect of
-          // the XOR is to toggle the bit.  If it is clear, then the ADD has
-          // no effect.
-          if ((AddRHS & AndRHSV) == 0) { // Bit is not set, noop
-            TheAnd.setOperand(0, X);
-            return &TheAnd;
-          } else {
-            // Pull the XOR out of the AND.
-            Value *NewAnd = Builder->CreateAnd(X, AndRHS);
-            NewAnd->takeName(Op);
-            return BinaryOperator::CreateXor(NewAnd, AndRHS);
-          }
-        }
-      }
-    }
-    break;
-
-  case Instruction::Shl: {
-    // We know that the AND will not produce any of the bits shifted in, so if
-    // the anded constant includes them, clear them now!
-    //
-    uint32_t BitWidth = AndRHS->getType()->getBitWidth();
-    uint32_t OpRHSVal = OpRHS->getLimitedValue(BitWidth);
-    APInt ShlMask(APInt::getHighBitsSet(BitWidth, BitWidth-OpRHSVal));
-    ConstantInt *CI = ConstantInt::get(*Context, AndRHS->getValue() & ShlMask);
-
-    if (CI->getValue() == ShlMask) { 
-    // Masking out bits that the shift already masks
-      return ReplaceInstUsesWith(TheAnd, Op);   // No need for the and.
-    } else if (CI != AndRHS) {                  // Reducing bits set in and.
-      TheAnd.setOperand(1, CI);
-      return &TheAnd;
-    }
-    break;
-  }
-  case Instruction::LShr:
-  {
-    // We know that the AND will not produce any of the bits shifted in, so if
-    // the anded constant includes them, clear them now!  This only applies to
-    // unsigned shifts, because a signed shr may bring in set bits!
-    //
-    uint32_t BitWidth = AndRHS->getType()->getBitWidth();
-    uint32_t OpRHSVal = OpRHS->getLimitedValue(BitWidth);
-    APInt ShrMask(APInt::getLowBitsSet(BitWidth, BitWidth - OpRHSVal));
-    ConstantInt *CI = ConstantInt::get(*Context, AndRHS->getValue() & ShrMask);
-
-    if (CI->getValue() == ShrMask) {   
-    // Masking out bits that the shift already masks.
-      return ReplaceInstUsesWith(TheAnd, Op);
-    } else if (CI != AndRHS) {
-      TheAnd.setOperand(1, CI);  // Reduce bits set in and cst.
-      return &TheAnd;
-    }
-    break;
-  }
-  case Instruction::AShr:
-    // Signed shr.
-    // See if this is shifting in some sign extension, then masking it out
-    // with an and.
-    if (Op->hasOneUse()) {
-      uint32_t BitWidth = AndRHS->getType()->getBitWidth();
-      uint32_t OpRHSVal = OpRHS->getLimitedValue(BitWidth);
-      APInt ShrMask(APInt::getLowBitsSet(BitWidth, BitWidth - OpRHSVal));
-      Constant *C = ConstantInt::get(*Context, AndRHS->getValue() & ShrMask);
-      if (C == AndRHS) {          // Masking out bits shifted in.
-        // (Val ashr C1) & C2 -> (Val lshr C1) & C2
-        // Make the argument unsigned.
-        Value *ShVal = Op->getOperand(0);
-        ShVal = Builder->CreateLShr(ShVal, OpRHS, Op->getName());
-        return BinaryOperator::CreateAnd(ShVal, AndRHS, TheAnd.getName());
-      }
-    }
-    break;
-  }
-  return 0;
-}
-
-
-/// InsertRangeTest - Emit a computation of: (V >= Lo && V < Hi) if Inside is
-/// true, otherwise (V < Lo || V >= Hi).  In pratice, we emit the more efficient
-/// (V-Lo) <u Hi-Lo.  This method expects that Lo <= Hi. isSigned indicates
-/// whether to treat the V, Lo and HI as signed or not. IB is the location to
-/// insert new instructions.
-Instruction *InstCombiner::InsertRangeTest(Value *V, Constant *Lo, Constant *Hi,
-                                           bool isSigned, bool Inside, 
-                                           Instruction &IB) {
-  assert(cast<ConstantInt>(ConstantExpr::getICmp((isSigned ? 
-            ICmpInst::ICMP_SLE:ICmpInst::ICMP_ULE), Lo, Hi))->getZExtValue() &&
-         "Lo is not <= Hi in range emission code!");
-    
-  if (Inside) {
-    if (Lo == Hi)  // Trivially false.
-      return new ICmpInst(ICmpInst::ICMP_NE, V, V);
-
-    // V >= Min && V < Hi --> V < Hi
-    if (cast<ConstantInt>(Lo)->isMinValue(isSigned)) {
-      ICmpInst::Predicate pred = (isSigned ? 
-        ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT);
-      return new ICmpInst(pred, V, Hi);
-    }
-
-    // Emit V-Lo <u Hi-Lo
-    Constant *NegLo = ConstantExpr::getNeg(Lo);
-    Value *Add = Builder->CreateAdd(V, NegLo, V->getName()+".off");
-    Constant *UpperBound = ConstantExpr::getAdd(NegLo, Hi);
-    return new ICmpInst(ICmpInst::ICMP_ULT, Add, UpperBound);
-  }
-
-  if (Lo == Hi)  // Trivially true.
-    return new ICmpInst(ICmpInst::ICMP_EQ, V, V);
-
-  // V < Min || V >= Hi -> V > Hi-1
-  Hi = SubOne(cast<ConstantInt>(Hi));
-  if (cast<ConstantInt>(Lo)->isMinValue(isSigned)) {
-    ICmpInst::Predicate pred = (isSigned ? 
-        ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT);
-    return new ICmpInst(pred, V, Hi);
-  }
-
-  // Emit V-Lo >u Hi-1-Lo
-  // Note that Hi has already had one subtracted from it, above.
-  ConstantInt *NegLo = cast<ConstantInt>(ConstantExpr::getNeg(Lo));
-  Value *Add = Builder->CreateAdd(V, NegLo, V->getName()+".off");
-  Constant *LowerBound = ConstantExpr::getAdd(NegLo, Hi);
-  return new ICmpInst(ICmpInst::ICMP_UGT, Add, LowerBound);
-}
-
-// isRunOfOnes - Returns true iff Val consists of one contiguous run of 1s with
-// any number of 0s on either side.  The 1s are allowed to wrap from LSB to
-// MSB, so 0x000FFF0, 0x0000FFFF, and 0xFF0000FF are all runs.  0x0F0F0000 is
-// not, since all 1s are not contiguous.
-static bool isRunOfOnes(ConstantInt *Val, uint32_t &MB, uint32_t &ME) {
-  const APInt& V = Val->getValue();
-  uint32_t BitWidth = Val->getType()->getBitWidth();
-  if (!APIntOps::isShiftedMask(BitWidth, V)) return false;
-
-  // look for the first zero bit after the run of ones
-  MB = BitWidth - ((V - 1) ^ V).countLeadingZeros();
-  // look for the first non-zero bit
-  ME = V.getActiveBits(); 
-  return true;
-}
-
-/// FoldLogicalPlusAnd - This is part of an expression (LHS +/- RHS) & Mask,
-/// where isSub determines whether the operator is a sub.  If we can fold one of
-/// the following xforms:
-/// 
-/// ((A & N) +/- B) & Mask -> (A +/- B) & Mask iff N&Mask == Mask
-/// ((A | N) +/- B) & Mask -> (A +/- B) & Mask iff N&Mask == 0
-/// ((A ^ N) +/- B) & Mask -> (A +/- B) & Mask iff N&Mask == 0
-///
-/// return (A +/- B).
-///
-Value *InstCombiner::FoldLogicalPlusAnd(Value *LHS, Value *RHS,
-                                        ConstantInt *Mask, bool isSub,
-                                        Instruction &I) {
-  Instruction *LHSI = dyn_cast<Instruction>(LHS);
-  if (!LHSI || LHSI->getNumOperands() != 2 ||
-      !isa<ConstantInt>(LHSI->getOperand(1))) return 0;
-
-  ConstantInt *N = cast<ConstantInt>(LHSI->getOperand(1));
-
-  switch (LHSI->getOpcode()) {
-  default: return 0;
-  case Instruction::And:
-    if (ConstantExpr::getAnd(N, Mask) == Mask) {
-      // If the AndRHS is a power of two minus one (0+1+), this is simple.
-      if ((Mask->getValue().countLeadingZeros() + 
-           Mask->getValue().countPopulation()) == 
-          Mask->getValue().getBitWidth())
-        break;
-
-      // Otherwise, if Mask is 0+1+0+, and if B is known to have the low 0+
-      // part, we don't need any explicit masks to take them out of A.  If that
-      // is all N is, ignore it.
-      uint32_t MB = 0, ME = 0;
-      if (isRunOfOnes(Mask, MB, ME)) {  // begin/end bit of run, inclusive
-        uint32_t BitWidth = cast<IntegerType>(RHS->getType())->getBitWidth();
-        APInt Mask(APInt::getLowBitsSet(BitWidth, MB-1));
-        if (MaskedValueIsZero(RHS, Mask))
-          break;
-      }
-    }
-    return 0;
-  case Instruction::Or:
-  case Instruction::Xor:
-    // If the AndRHS is a power of two minus one (0+1+), and N&Mask == 0
-    if ((Mask->getValue().countLeadingZeros() + 
-         Mask->getValue().countPopulation()) == Mask->getValue().getBitWidth()
-        && ConstantExpr::getAnd(N, Mask)->isNullValue())
-      break;
-    return 0;
-  }
-  
-  if (isSub)
-    return Builder->CreateSub(LHSI->getOperand(0), RHS, "fold");
-  return Builder->CreateAdd(LHSI->getOperand(0), RHS, "fold");
-}
-
-/// FoldAndOfICmps - Fold (icmp)&(icmp) if possible.
-Instruction *InstCombiner::FoldAndOfICmps(Instruction &I,
-                                          ICmpInst *LHS, ICmpInst *RHS) {
-  Value *Val, *Val2;
-  ConstantInt *LHSCst, *RHSCst;
-  ICmpInst::Predicate LHSCC, RHSCC;
-  
-  // This only handles icmp of constants: (icmp1 A, C1) & (icmp2 B, C2).
-  if (!match(LHS, m_ICmp(LHSCC, m_Value(Val),
-                         m_ConstantInt(LHSCst))) ||
-      !match(RHS, m_ICmp(RHSCC, m_Value(Val2),
-                         m_ConstantInt(RHSCst))))
-    return 0;
-  
-  if (LHSCst == RHSCst && LHSCC == RHSCC) {
-    // (icmp ult A, C) & (icmp ult B, C) --> (icmp ult (A|B), C)
-    // where C is a power of 2
-    if (LHSCC == ICmpInst::ICMP_ULT &&
-        LHSCst->getValue().isPowerOf2()) {
-      Value *NewOr = Builder->CreateOr(Val, Val2);
-      return new ICmpInst(LHSCC, NewOr, LHSCst);
-    }
-    
-    // (icmp eq A, 0) & (icmp eq B, 0) --> (icmp eq (A|B), 0)
-    if (LHSCC == ICmpInst::ICMP_EQ && LHSCst->isZero()) {
-      Value *NewOr = Builder->CreateOr(Val, Val2);
-      return new ICmpInst(LHSCC, NewOr, LHSCst);
-    }
-  }
-  
-  // From here on, we only handle:
-  //    (icmp1 A, C1) & (icmp2 A, C2) --> something simpler.
-  if (Val != Val2) return 0;
-  
-  // ICMP_[US][GL]E X, CST is folded to ICMP_[US][GL]T elsewhere.
-  if (LHSCC == ICmpInst::ICMP_UGE || LHSCC == ICmpInst::ICMP_ULE ||
-      RHSCC == ICmpInst::ICMP_UGE || RHSCC == ICmpInst::ICMP_ULE ||
-      LHSCC == ICmpInst::ICMP_SGE || LHSCC == ICmpInst::ICMP_SLE ||
-      RHSCC == ICmpInst::ICMP_SGE || RHSCC == ICmpInst::ICMP_SLE)
-    return 0;
-  
-  // We can't fold (ugt x, C) & (sgt x, C2).
-  if (!PredicatesFoldable(LHSCC, RHSCC))
-    return 0;
-    
-  // Ensure that the larger constant is on the RHS.
-  bool ShouldSwap;
-  if (CmpInst::isSigned(LHSCC) ||
-      (ICmpInst::isEquality(LHSCC) && 
-       CmpInst::isSigned(RHSCC)))
-    ShouldSwap = LHSCst->getValue().sgt(RHSCst->getValue());
-  else
-    ShouldSwap = LHSCst->getValue().ugt(RHSCst->getValue());
-    
-  if (ShouldSwap) {
-    std::swap(LHS, RHS);
-    std::swap(LHSCst, RHSCst);
-    std::swap(LHSCC, RHSCC);
-  }
-
-  // At this point, we know we have have two icmp instructions
-  // comparing a value against two constants and and'ing the result
-  // together.  Because of the above check, we know that we only have
-  // icmp eq, icmp ne, icmp [su]lt, and icmp [SU]gt here. We also know 
-  // (from the FoldICmpLogical check above), that the two constants 
-  // are not equal and that the larger constant is on the RHS
-  assert(LHSCst != RHSCst && "Compares not folded above?");
-
-  switch (LHSCC) {
-  default: llvm_unreachable("Unknown integer condition code!");
-  case ICmpInst::ICMP_EQ:
-    switch (RHSCC) {
-    default: llvm_unreachable("Unknown integer condition code!");
-    case ICmpInst::ICMP_EQ:         // (X == 13 & X == 15) -> false
-    case ICmpInst::ICMP_UGT:        // (X == 13 & X >  15) -> false
-    case ICmpInst::ICMP_SGT:        // (X == 13 & X >  15) -> false
-      return ReplaceInstUsesWith(I, ConstantInt::getFalse(*Context));
-    case ICmpInst::ICMP_NE:         // (X == 13 & X != 15) -> X == 13
-    case ICmpInst::ICMP_ULT:        // (X == 13 & X <  15) -> X == 13
-    case ICmpInst::ICMP_SLT:        // (X == 13 & X <  15) -> X == 13
-      return ReplaceInstUsesWith(I, LHS);
-    }
-  case ICmpInst::ICMP_NE:
-    switch (RHSCC) {
-    default: llvm_unreachable("Unknown integer condition code!");
-    case ICmpInst::ICMP_ULT:
-      if (LHSCst == SubOne(RHSCst)) // (X != 13 & X u< 14) -> X < 13
-        return new ICmpInst(ICmpInst::ICMP_ULT, Val, LHSCst);
-      break;                        // (X != 13 & X u< 15) -> no change
-    case ICmpInst::ICMP_SLT:
-      if (LHSCst == SubOne(RHSCst)) // (X != 13 & X s< 14) -> X < 13
-        return new ICmpInst(ICmpInst::ICMP_SLT, Val, LHSCst);
-      break;                        // (X != 13 & X s< 15) -> no change
-    case ICmpInst::ICMP_EQ:         // (X != 13 & X == 15) -> X == 15
-    case ICmpInst::ICMP_UGT:        // (X != 13 & X u> 15) -> X u> 15
-    case ICmpInst::ICMP_SGT:        // (X != 13 & X s> 15) -> X s> 15
-      return ReplaceInstUsesWith(I, RHS);
-    case ICmpInst::ICMP_NE:
-      if (LHSCst == SubOne(RHSCst)){// (X != 13 & X != 14) -> X-13 >u 1
-        Constant *AddCST = ConstantExpr::getNeg(LHSCst);
-        Value *Add = Builder->CreateAdd(Val, AddCST, Val->getName()+".off");
-        return new ICmpInst(ICmpInst::ICMP_UGT, Add,
-                            ConstantInt::get(Add->getType(), 1));
-      }
-      break;                        // (X != 13 & X != 15) -> no change
-    }
-    break;
-  case ICmpInst::ICMP_ULT:
-    switch (RHSCC) {
-    default: llvm_unreachable("Unknown integer condition code!");
-    case ICmpInst::ICMP_EQ:         // (X u< 13 & X == 15) -> false
-    case ICmpInst::ICMP_UGT:        // (X u< 13 & X u> 15) -> false
-      return ReplaceInstUsesWith(I, ConstantInt::getFalse(*Context));
-    case ICmpInst::ICMP_SGT:        // (X u< 13 & X s> 15) -> no change
-      break;
-    case ICmpInst::ICMP_NE:         // (X u< 13 & X != 15) -> X u< 13
-    case ICmpInst::ICMP_ULT:        // (X u< 13 & X u< 15) -> X u< 13
-      return ReplaceInstUsesWith(I, LHS);
-    case ICmpInst::ICMP_SLT:        // (X u< 13 & X s< 15) -> no change
-      break;
-    }
-    break;
-  case ICmpInst::ICMP_SLT:
-    switch (RHSCC) {
-    default: llvm_unreachable("Unknown integer condition code!");
-    case ICmpInst::ICMP_EQ:         // (X s< 13 & X == 15) -> false
-    case ICmpInst::ICMP_SGT:        // (X s< 13 & X s> 15) -> false
-      return ReplaceInstUsesWith(I, ConstantInt::getFalse(*Context));
-    case ICmpInst::ICMP_UGT:        // (X s< 13 & X u> 15) -> no change
-      break;
-    case ICmpInst::ICMP_NE:         // (X s< 13 & X != 15) -> X < 13
-    case ICmpInst::ICMP_SLT:        // (X s< 13 & X s< 15) -> X < 13
-      return ReplaceInstUsesWith(I, LHS);
-    case ICmpInst::ICMP_ULT:        // (X s< 13 & X u< 15) -> no change
-      break;
-    }
-    break;
-  case ICmpInst::ICMP_UGT:
-    switch (RHSCC) {
-    default: llvm_unreachable("Unknown integer condition code!");
-    case ICmpInst::ICMP_EQ:         // (X u> 13 & X == 15) -> X == 15
-    case ICmpInst::ICMP_UGT:        // (X u> 13 & X u> 15) -> X u> 15
-      return ReplaceInstUsesWith(I, RHS);
-    case ICmpInst::ICMP_SGT:        // (X u> 13 & X s> 15) -> no change
-      break;
-    case ICmpInst::ICMP_NE:
-      if (RHSCst == AddOne(LHSCst)) // (X u> 13 & X != 14) -> X u> 14
-        return new ICmpInst(LHSCC, Val, RHSCst);
-      break;                        // (X u> 13 & X != 15) -> no change
-    case ICmpInst::ICMP_ULT:        // (X u> 13 & X u< 15) -> (X-14) <u 1
-      return InsertRangeTest(Val, AddOne(LHSCst),
-                             RHSCst, false, true, I);
-    case ICmpInst::ICMP_SLT:        // (X u> 13 & X s< 15) -> no change
-      break;
-    }
-    break;
-  case ICmpInst::ICMP_SGT:
-    switch (RHSCC) {
-    default: llvm_unreachable("Unknown integer condition code!");
-    case ICmpInst::ICMP_EQ:         // (X s> 13 & X == 15) -> X == 15
-    case ICmpInst::ICMP_SGT:        // (X s> 13 & X s> 15) -> X s> 15
-      return ReplaceInstUsesWith(I, RHS);
-    case ICmpInst::ICMP_UGT:        // (X s> 13 & X u> 15) -> no change
-      break;
-    case ICmpInst::ICMP_NE:
-      if (RHSCst == AddOne(LHSCst)) // (X s> 13 & X != 14) -> X s> 14
-        return new ICmpInst(LHSCC, Val, RHSCst);
-      break;                        // (X s> 13 & X != 15) -> no change
-    case ICmpInst::ICMP_SLT:        // (X s> 13 & X s< 15) -> (X-14) s< 1
-      return InsertRangeTest(Val, AddOne(LHSCst),
-                             RHSCst, true, true, I);
-    case ICmpInst::ICMP_ULT:        // (X s> 13 & X u< 15) -> no change
-      break;
-    }
-    break;
-  }
- 
-  return 0;
-}
-
-Instruction *InstCombiner::FoldAndOfFCmps(Instruction &I, FCmpInst *LHS,
-                                          FCmpInst *RHS) {
-  
-  if (LHS->getPredicate() == FCmpInst::FCMP_ORD &&
-      RHS->getPredicate() == FCmpInst::FCMP_ORD) {
-    // (fcmp ord x, c) & (fcmp ord y, c)  -> (fcmp ord x, y)
-    if (ConstantFP *LHSC = dyn_cast<ConstantFP>(LHS->getOperand(1)))
-      if (ConstantFP *RHSC = dyn_cast<ConstantFP>(RHS->getOperand(1))) {
-        // If either of the constants are nans, then the whole thing returns
-        // false.
-        if (LHSC->getValueAPF().isNaN() || RHSC->getValueAPF().isNaN())
-          return ReplaceInstUsesWith(I, ConstantInt::getFalse(*Context));
-        return new FCmpInst(FCmpInst::FCMP_ORD,
-                            LHS->getOperand(0), RHS->getOperand(0));
-      }
-    
-    // Handle vector zeros.  This occurs because the canonical form of
-    // "fcmp ord x,x" is "fcmp ord x, 0".
-    if (isa<ConstantAggregateZero>(LHS->getOperand(1)) &&
-        isa<ConstantAggregateZero>(RHS->getOperand(1)))
-      return new FCmpInst(FCmpInst::FCMP_ORD,
-                          LHS->getOperand(0), RHS->getOperand(0));
-    return 0;
-  }
-  
-  Value *Op0LHS = LHS->getOperand(0), *Op0RHS = LHS->getOperand(1);
-  Value *Op1LHS = RHS->getOperand(0), *Op1RHS = RHS->getOperand(1);
-  FCmpInst::Predicate Op0CC = LHS->getPredicate(), Op1CC = RHS->getPredicate();
-  
-  
-  if (Op0LHS == Op1RHS && Op0RHS == Op1LHS) {
-    // Swap RHS operands to match LHS.
-    Op1CC = FCmpInst::getSwappedPredicate(Op1CC);
-    std::swap(Op1LHS, Op1RHS);
-  }
-  
-  if (Op0LHS == Op1LHS && Op0RHS == Op1RHS) {
-    // Simplify (fcmp cc0 x, y) & (fcmp cc1 x, y).
-    if (Op0CC == Op1CC)
-      return new FCmpInst((FCmpInst::Predicate)Op0CC, Op0LHS, Op0RHS);
-    
-    if (Op0CC == FCmpInst::FCMP_FALSE || Op1CC == FCmpInst::FCMP_FALSE)
-      return ReplaceInstUsesWith(I, ConstantInt::getFalse(*Context));
-    if (Op0CC == FCmpInst::FCMP_TRUE)
-      return ReplaceInstUsesWith(I, RHS);
-    if (Op1CC == FCmpInst::FCMP_TRUE)
-      return ReplaceInstUsesWith(I, LHS);
-    
-    bool Op0Ordered;
-    bool Op1Ordered;
-    unsigned Op0Pred = getFCmpCode(Op0CC, Op0Ordered);
-    unsigned Op1Pred = getFCmpCode(Op1CC, Op1Ordered);
-    if (Op1Pred == 0) {
-      std::swap(LHS, RHS);
-      std::swap(Op0Pred, Op1Pred);
-      std::swap(Op0Ordered, Op1Ordered);
-    }
-    if (Op0Pred == 0) {
-      // uno && ueq -> uno && (uno || eq) -> ueq
-      // ord && olt -> ord && (ord && lt) -> olt
-      if (Op0Ordered == Op1Ordered)
-        return ReplaceInstUsesWith(I, RHS);
-      
-      // uno && oeq -> uno && (ord && eq) -> false
-      // uno && ord -> false
-      if (!Op0Ordered)
-        return ReplaceInstUsesWith(I, ConstantInt::getFalse(*Context));
-      // ord && ueq -> ord && (uno || eq) -> oeq
-      return cast<Instruction>(getFCmpValue(true, Op1Pred,
-                                            Op0LHS, Op0RHS, Context));
-    }
-  }
-
-  return 0;
-}
-
-
-Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
-  bool Changed = SimplifyCommutative(I);
-  Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
-  if (Value *V = SimplifyAndInst(Op0, Op1, TD))
-    return ReplaceInstUsesWith(I, V);
-
-  // See if we can simplify any instructions used by the instruction whose sole 
-  // purpose is to compute bits we don't care about.
-  if (SimplifyDemandedInstructionBits(I))
-    return &I;  
-
-  if (ConstantInt *AndRHS = dyn_cast<ConstantInt>(Op1)) {
-    const APInt &AndRHSMask = AndRHS->getValue();
-    APInt NotAndRHS(~AndRHSMask);
-
-    // Optimize a variety of ((val OP C1) & C2) combinations...
-    if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) {
-      Value *Op0LHS = Op0I->getOperand(0);
-      Value *Op0RHS = Op0I->getOperand(1);
-      switch (Op0I->getOpcode()) {
-      default: break;
-      case Instruction::Xor:
-      case Instruction::Or:
-        // If the mask is only needed on one incoming arm, push it up.
-        if (!Op0I->hasOneUse()) break;
-          
-        if (MaskedValueIsZero(Op0LHS, NotAndRHS)) {
-          // Not masking anything out for the LHS, move to RHS.
-          Value *NewRHS = Builder->CreateAnd(Op0RHS, AndRHS,
-                                             Op0RHS->getName()+".masked");
-          return BinaryOperator::Create(Op0I->getOpcode(), Op0LHS, NewRHS);
-        }
-        if (!isa<Constant>(Op0RHS) &&
-            MaskedValueIsZero(Op0RHS, NotAndRHS)) {
-          // Not masking anything out for the RHS, move to LHS.
-          Value *NewLHS = Builder->CreateAnd(Op0LHS, AndRHS,
-                                             Op0LHS->getName()+".masked");
-          return BinaryOperator::Create(Op0I->getOpcode(), NewLHS, Op0RHS);
-        }
-
-        break;
-      case Instruction::Add:
-        // ((A & N) + B) & AndRHS -> (A + B) & AndRHS iff N&AndRHS == AndRHS.
-        // ((A | N) + B) & AndRHS -> (A + B) & AndRHS iff N&AndRHS == 0
-        // ((A ^ N) + B) & AndRHS -> (A + B) & AndRHS iff N&AndRHS == 0
-        if (Value *V = FoldLogicalPlusAnd(Op0LHS, Op0RHS, AndRHS, false, I))
-          return BinaryOperator::CreateAnd(V, AndRHS);
-        if (Value *V = FoldLogicalPlusAnd(Op0RHS, Op0LHS, AndRHS, false, I))
-          return BinaryOperator::CreateAnd(V, AndRHS);  // Add commutes
-        break;
-
-      case Instruction::Sub:
-        // ((A & N) - B) & AndRHS -> (A - B) & AndRHS iff N&AndRHS == AndRHS.
-        // ((A | N) - B) & AndRHS -> (A - B) & AndRHS iff N&AndRHS == 0
-        // ((A ^ N) - B) & AndRHS -> (A - B) & AndRHS iff N&AndRHS == 0
-        if (Value *V = FoldLogicalPlusAnd(Op0LHS, Op0RHS, AndRHS, true, I))
-          return BinaryOperator::CreateAnd(V, AndRHS);
-
-        // (A - N) & AndRHS -> -N & AndRHS iff A&AndRHS==0 and AndRHS
-        // has 1's for all bits that the subtraction with A might affect.
-        if (Op0I->hasOneUse()) {
-          uint32_t BitWidth = AndRHSMask.getBitWidth();
-          uint32_t Zeros = AndRHSMask.countLeadingZeros();
-          APInt Mask = APInt::getLowBitsSet(BitWidth, BitWidth - Zeros);
-
-          ConstantInt *A = dyn_cast<ConstantInt>(Op0LHS);
-          if (!(A && A->isZero()) &&               // avoid infinite recursion.
-              MaskedValueIsZero(Op0LHS, Mask)) {
-            Value *NewNeg = Builder->CreateNeg(Op0RHS);
-            return BinaryOperator::CreateAnd(NewNeg, AndRHS);
-          }
-        }
-        break;
-
-      case Instruction::Shl:
-      case Instruction::LShr:
-        // (1 << x) & 1 --> zext(x == 0)
-        // (1 >> x) & 1 --> zext(x == 0)
-        if (AndRHSMask == 1 && Op0LHS == AndRHS) {
-          Value *NewICmp =
-            Builder->CreateICmpEQ(Op0RHS, Constant::getNullValue(I.getType()));
-          return new ZExtInst(NewICmp, I.getType());
-        }
-        break;
-      }
-
-      if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1)))
-        if (Instruction *Res = OptAndOp(Op0I, Op0CI, AndRHS, I))
-          return Res;
-    } else if (CastInst *CI = dyn_cast<CastInst>(Op0)) {
-      // If this is an integer truncation or change from signed-to-unsigned, and
-      // if the source is an and/or with immediate, transform it.  This
-      // frequently occurs for bitfield accesses.
-      if (Instruction *CastOp = dyn_cast<Instruction>(CI->getOperand(0))) {
-        if ((isa<TruncInst>(CI) || isa<BitCastInst>(CI)) &&
-            CastOp->getNumOperands() == 2)
-          if (ConstantInt *AndCI =dyn_cast<ConstantInt>(CastOp->getOperand(1))){
-            if (CastOp->getOpcode() == Instruction::And) {
-              // Change: and (cast (and X, C1) to T), C2
-              // into  : and (cast X to T), trunc_or_bitcast(C1)&C2
-              // This will fold the two constants together, which may allow 
-              // other simplifications.
-              Value *NewCast = Builder->CreateTruncOrBitCast(
-                CastOp->getOperand(0), I.getType(), 
-                CastOp->getName()+".shrunk");
-              // trunc_or_bitcast(C1)&C2
-              Constant *C3 = ConstantExpr::getTruncOrBitCast(AndCI,I.getType());
-              C3 = ConstantExpr::getAnd(C3, AndRHS);
-              return BinaryOperator::CreateAnd(NewCast, C3);
-            } else if (CastOp->getOpcode() == Instruction::Or) {
-              // Change: and (cast (or X, C1) to T), C2
-              // into  : trunc(C1)&C2 iff trunc(C1)&C2 == C2
-              Constant *C3 = ConstantExpr::getTruncOrBitCast(AndCI,I.getType());
-              if (ConstantExpr::getAnd(C3, AndRHS) == AndRHS)
-                // trunc(C1)&C2
-                return ReplaceInstUsesWith(I, AndRHS);
-            }
-          }
-      }
-    }
-
-    // Try to fold constant and into select arguments.
-    if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
-      if (Instruction *R = FoldOpIntoSelect(I, SI, this))
-        return R;
-    if (isa<PHINode>(Op0))
-      if (Instruction *NV = FoldOpIntoPhi(I))
-        return NV;
-  }
-
-
-  // (~A & ~B) == (~(A | B)) - De Morgan's Law
-  if (Value *Op0NotVal = dyn_castNotVal(Op0))
-    if (Value *Op1NotVal = dyn_castNotVal(Op1))
-      if (Op0->hasOneUse() && Op1->hasOneUse()) {
-        Value *Or = Builder->CreateOr(Op0NotVal, Op1NotVal,
-                                      I.getName()+".demorgan");
-        return BinaryOperator::CreateNot(Or);
-      }
-
-  {
-    Value *A = 0, *B = 0, *C = 0, *D = 0;
-    // (A|B) & ~(A&B) -> A^B
-    if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
-        match(Op1, m_Not(m_And(m_Value(C), m_Value(D)))) &&
-        ((A == C && B == D) || (A == D && B == C)))
-      return BinaryOperator::CreateXor(A, B);
-    
-    // ~(A&B) & (A|B) -> A^B
-    if (match(Op1, m_Or(m_Value(A), m_Value(B))) &&
-        match(Op0, m_Not(m_And(m_Value(C), m_Value(D)))) &&
-        ((A == C && B == D) || (A == D && B == C)))
-      return BinaryOperator::CreateXor(A, B);
-    
-    if (Op0->hasOneUse() &&
-        match(Op0, m_Xor(m_Value(A), m_Value(B)))) {
-      if (A == Op1) {                                // (A^B)&A -> A&(A^B)
-        I.swapOperands();     // Simplify below
-        std::swap(Op0, Op1);
-      } else if (B == Op1) {                         // (A^B)&B -> B&(B^A)
-        cast<BinaryOperator>(Op0)->swapOperands();
-        I.swapOperands();     // Simplify below
-        std::swap(Op0, Op1);
-      }
-    }
-
-    if (Op1->hasOneUse() &&
-        match(Op1, m_Xor(m_Value(A), m_Value(B)))) {
-      if (B == Op0) {                                // B&(A^B) -> B&(B^A)
-        cast<BinaryOperator>(Op1)->swapOperands();
-        std::swap(A, B);
-      }
-      if (A == Op0)                                // A&(A^B) -> A & ~B
-        return BinaryOperator::CreateAnd(A, Builder->CreateNot(B, "tmp"));
-    }
-
-    // (A&((~A)|B)) -> A&B
-    if (match(Op0, m_Or(m_Not(m_Specific(Op1)), m_Value(A))) ||
-        match(Op0, m_Or(m_Value(A), m_Not(m_Specific(Op1)))))
-      return BinaryOperator::CreateAnd(A, Op1);
-    if (match(Op1, m_Or(m_Not(m_Specific(Op0)), m_Value(A))) ||
-        match(Op1, m_Or(m_Value(A), m_Not(m_Specific(Op0)))))
-      return BinaryOperator::CreateAnd(A, Op0);
-  }
-  
-  if (ICmpInst *RHS = dyn_cast<ICmpInst>(Op1)) {
-    // (icmp1 A, B) & (icmp2 A, B) --> (icmp3 A, B)
-    if (Instruction *R = AssociativeOpt(I, FoldICmpLogical(*this, RHS)))
-      return R;
-
-    if (ICmpInst *LHS = dyn_cast<ICmpInst>(Op0))
-      if (Instruction *Res = FoldAndOfICmps(I, LHS, RHS))
-        return Res;
-  }
-
-  // fold (and (cast A), (cast B)) -> (cast (and A, B))
-  if (CastInst *Op0C = dyn_cast<CastInst>(Op0))
-    if (CastInst *Op1C = dyn_cast<CastInst>(Op1))
-      if (Op0C->getOpcode() == Op1C->getOpcode()) { // same cast kind ?
-        const Type *SrcTy = Op0C->getOperand(0)->getType();
-        if (SrcTy == Op1C->getOperand(0)->getType() &&
-            SrcTy->isIntOrIntVector() &&
-            // Only do this if the casts both really cause code to be generated.
-            ValueRequiresCast(Op0C->getOpcode(), Op0C->getOperand(0), 
-                              I.getType(), TD) &&
-            ValueRequiresCast(Op1C->getOpcode(), Op1C->getOperand(0), 
-                              I.getType(), TD)) {
-          Value *NewOp = Builder->CreateAnd(Op0C->getOperand(0),
-                                            Op1C->getOperand(0), I.getName());
-          return CastInst::Create(Op0C->getOpcode(), NewOp, I.getType());
-        }
-      }
-    
-  // (X >> Z) & (Y >> Z)  -> (X&Y) >> Z  for all shifts.
-  if (BinaryOperator *SI1 = dyn_cast<BinaryOperator>(Op1)) {
-    if (BinaryOperator *SI0 = dyn_cast<BinaryOperator>(Op0))
-      if (SI0->isShift() && SI0->getOpcode() == SI1->getOpcode() && 
-          SI0->getOperand(1) == SI1->getOperand(1) &&
-          (SI0->hasOneUse() || SI1->hasOneUse())) {
-        Value *NewOp =
-          Builder->CreateAnd(SI0->getOperand(0), SI1->getOperand(0),
-                             SI0->getName());
-        return BinaryOperator::Create(SI1->getOpcode(), NewOp, 
-                                      SI1->getOperand(1));
-      }
-  }
-
-  // If and'ing two fcmp, try combine them into one.
-  if (FCmpInst *LHS = dyn_cast<FCmpInst>(I.getOperand(0))) {
-    if (FCmpInst *RHS = dyn_cast<FCmpInst>(I.getOperand(1)))
-      if (Instruction *Res = FoldAndOfFCmps(I, LHS, RHS))
-        return Res;
-  }
-
-  return Changed ? &I : 0;
-}
-
-/// CollectBSwapParts - Analyze the specified subexpression and see if it is
-/// capable of providing pieces of a bswap.  The subexpression provides pieces
-/// of a bswap if it is proven that each of the non-zero bytes in the output of
-/// the expression came from the corresponding "byte swapped" byte in some other
-/// value.  For example, if the current subexpression is "(shl i32 %X, 24)" then
-/// we know that the expression deposits the low byte of %X into the high byte
-/// of the bswap result and that all other bytes are zero.  This expression is
-/// accepted, the high byte of ByteValues is set to X to indicate a correct
-/// match.
-///
-/// This function returns true if the match was unsuccessful and false if so.
-/// On entry to the function the "OverallLeftShift" is a signed integer value
-/// indicating the number of bytes that the subexpression is later shifted.  For
-/// example, if the expression is later right shifted by 16 bits, the
-/// OverallLeftShift value would be -2 on entry.  This is used to specify which
-/// byte of ByteValues is actually being set.
-///
-/// Similarly, ByteMask is a bitmask where a bit is clear if its corresponding
-/// byte is masked to zero by a user.  For example, in (X & 255), X will be
-/// processed with a bytemask of 1.  Because bytemask is 32-bits, this limits
-/// this function to working on up to 32-byte (256 bit) values.  ByteMask is
-/// always in the local (OverallLeftShift) coordinate space.
-///
-static bool CollectBSwapParts(Value *V, int OverallLeftShift, uint32_t ByteMask,
-                              SmallVector<Value*, 8> &ByteValues) {
-  if (Instruction *I = dyn_cast<Instruction>(V)) {
-    // If this is an or instruction, it may be an inner node of the bswap.
-    if (I->getOpcode() == Instruction::Or) {
-      return CollectBSwapParts(I->getOperand(0), OverallLeftShift, ByteMask,
-                               ByteValues) ||
-             CollectBSwapParts(I->getOperand(1), OverallLeftShift, ByteMask,
-                               ByteValues);
-    }
-  
-    // If this is a logical shift by a constant multiple of 8, recurse with
-    // OverallLeftShift and ByteMask adjusted.
-    if (I->isLogicalShift() && isa<ConstantInt>(I->getOperand(1))) {
-      unsigned ShAmt = 
-        cast<ConstantInt>(I->getOperand(1))->getLimitedValue(~0U);
-      // Ensure the shift amount is defined and of a byte value.
-      if ((ShAmt & 7) || (ShAmt > 8*ByteValues.size()))
-        return true;
-
-      unsigned ByteShift = ShAmt >> 3;
-      if (I->getOpcode() == Instruction::Shl) {
-        // X << 2 -> collect(X, +2)
-        OverallLeftShift += ByteShift;
-        ByteMask >>= ByteShift;
-      } else {
-        // X >>u 2 -> collect(X, -2)
-        OverallLeftShift -= ByteShift;
-        ByteMask <<= ByteShift;
-        ByteMask &= (~0U >> (32-ByteValues.size()));
-      }
-
-      if (OverallLeftShift >= (int)ByteValues.size()) return true;
-      if (OverallLeftShift <= -(int)ByteValues.size()) return true;
-
-      return CollectBSwapParts(I->getOperand(0), OverallLeftShift, ByteMask, 
-                               ByteValues);
-    }
-
-    // If this is a logical 'and' with a mask that clears bytes, clear the
-    // corresponding bytes in ByteMask.
-    if (I->getOpcode() == Instruction::And &&
-        isa<ConstantInt>(I->getOperand(1))) {
-      // Scan every byte of the and mask, seeing if the byte is either 0 or 255.
-      unsigned NumBytes = ByteValues.size();
-      APInt Byte(I->getType()->getPrimitiveSizeInBits(), 255);
-      const APInt &AndMask = cast<ConstantInt>(I->getOperand(1))->getValue();
-      
-      for (unsigned i = 0; i != NumBytes; ++i, Byte <<= 8) {
-        // If this byte is masked out by a later operation, we don't care what
-        // the and mask is.
-        if ((ByteMask & (1 << i)) == 0)
-          continue;
-        
-        // If the AndMask is all zeros for this byte, clear the bit.
-        APInt MaskB = AndMask & Byte;
-        if (MaskB == 0) {
-          ByteMask &= ~(1U << i);
-          continue;
-        }
-        
-        // If the AndMask is not all ones for this byte, it's not a bytezap.
-        if (MaskB != Byte)
-          return true;
-
-        // Otherwise, this byte is kept.
-      }
-
-      return CollectBSwapParts(I->getOperand(0), OverallLeftShift, ByteMask, 
-                               ByteValues);
-    }
-  }
-  
-  // Okay, we got to something that isn't a shift, 'or' or 'and'.  This must be
-  // the input value to the bswap.  Some observations: 1) if more than one byte
-  // is demanded from this input, then it could not be successfully assembled
-  // into a byteswap.  At least one of the two bytes would not be aligned with
-  // their ultimate destination.
-  if (!isPowerOf2_32(ByteMask)) return true;
-  unsigned InputByteNo = CountTrailingZeros_32(ByteMask);
-  
-  // 2) The input and ultimate destinations must line up: if byte 3 of an i32
-  // is demanded, it needs to go into byte 0 of the result.  This means that the
-  // byte needs to be shifted until it lands in the right byte bucket.  The
-  // shift amount depends on the position: if the byte is coming from the high
-  // part of the value (e.g. byte 3) then it must be shifted right.  If from the
-  // low part, it must be shifted left.
-  unsigned DestByteNo = InputByteNo + OverallLeftShift;
-  if (InputByteNo < ByteValues.size()/2) {
-    if (ByteValues.size()-1-DestByteNo != InputByteNo)
-      return true;
-  } else {
-    if (ByteValues.size()-1-DestByteNo != InputByteNo)
-      return true;
-  }
-  
-  // If the destination byte value is already defined, the values are or'd
-  // together, which isn't a bswap (unless it's an or of the same bits).
-  if (ByteValues[DestByteNo] && ByteValues[DestByteNo] != V)
-    return true;
-  ByteValues[DestByteNo] = V;
-  return false;
-}
-
-/// MatchBSwap - Given an OR instruction, check to see if this is a bswap idiom.
-/// If so, insert the new bswap intrinsic and return it.
-Instruction *InstCombiner::MatchBSwap(BinaryOperator &I) {
-  const IntegerType *ITy = dyn_cast<IntegerType>(I.getType());
-  if (!ITy || ITy->getBitWidth() % 16 || 
-      // ByteMask only allows up to 32-byte values.
-      ITy->getBitWidth() > 32*8) 
-    return 0;   // Can only bswap pairs of bytes.  Can't do vectors.
-  
-  /// ByteValues - For each byte of the result, we keep track of which value
-  /// defines each byte.
-  SmallVector<Value*, 8> ByteValues;
-  ByteValues.resize(ITy->getBitWidth()/8);
-    
-  // Try to find all the pieces corresponding to the bswap.
-  uint32_t ByteMask = ~0U >> (32-ByteValues.size());
-  if (CollectBSwapParts(&I, 0, ByteMask, ByteValues))
-    return 0;
-  
-  // Check to see if all of the bytes come from the same value.
-  Value *V = ByteValues[0];
-  if (V == 0) return 0;  // Didn't find a byte?  Must be zero.
-  
-  // Check to make sure that all of the bytes come from the same value.
-  for (unsigned i = 1, e = ByteValues.size(); i != e; ++i)
-    if (ByteValues[i] != V)
-      return 0;
-  const Type *Tys[] = { ITy };
-  Module *M = I.getParent()->getParent()->getParent();
-  Function *F = Intrinsic::getDeclaration(M, Intrinsic::bswap, Tys, 1);
-  return CallInst::Create(F, V);
-}
-
-/// MatchSelectFromAndOr - We have an expression of the form (A&C)|(B&D).  Check
-/// If A is (cond?-1:0) and either B or D is ~(cond?-1,0) or (cond?0,-1), then
-/// we can simplify this expression to "cond ? C : D or B".
-static Instruction *MatchSelectFromAndOr(Value *A, Value *B,
-                                         Value *C, Value *D,
-                                         LLVMContext *Context) {
-  // If A is not a select of -1/0, this cannot match.
-  Value *Cond = 0;
-  if (!match(A, m_SelectCst<-1, 0>(m_Value(Cond))))
-    return 0;
-
-  // ((cond?-1:0)&C) | (B&(cond?0:-1)) -> cond ? C : B.
-  if (match(D, m_SelectCst<0, -1>(m_Specific(Cond))))
-    return SelectInst::Create(Cond, C, B);
-  if (match(D, m_Not(m_SelectCst<-1, 0>(m_Specific(Cond)))))
-    return SelectInst::Create(Cond, C, B);
-  // ((cond?-1:0)&C) | ((cond?0:-1)&D) -> cond ? C : D.
-  if (match(B, m_SelectCst<0, -1>(m_Specific(Cond))))
-    return SelectInst::Create(Cond, C, D);
-  if (match(B, m_Not(m_SelectCst<-1, 0>(m_Specific(Cond)))))
-    return SelectInst::Create(Cond, C, D);
-  return 0;
-}
-
-/// FoldOrOfICmps - Fold (icmp)|(icmp) if possible.
-Instruction *InstCombiner::FoldOrOfICmps(Instruction &I,
-                                         ICmpInst *LHS, ICmpInst *RHS) {
-  Value *Val, *Val2;
-  ConstantInt *LHSCst, *RHSCst;
-  ICmpInst::Predicate LHSCC, RHSCC;
-  
-  // This only handles icmp of constants: (icmp1 A, C1) | (icmp2 B, C2).
-  if (!match(LHS, m_ICmp(LHSCC, m_Value(Val), m_ConstantInt(LHSCst))) ||
-      !match(RHS, m_ICmp(RHSCC, m_Value(Val2), m_ConstantInt(RHSCst))))
-    return 0;
-
-  
-  // (icmp ne A, 0) | (icmp ne B, 0) --> (icmp ne (A|B), 0)
-  if (LHSCst == RHSCst && LHSCC == RHSCC &&
-      LHSCC == ICmpInst::ICMP_NE && LHSCst->isZero()) {
-    Value *NewOr = Builder->CreateOr(Val, Val2);
-    return new ICmpInst(LHSCC, NewOr, LHSCst);
-  }
-  
-  // From here on, we only handle:
-  //    (icmp1 A, C1) | (icmp2 A, C2) --> something simpler.
-  if (Val != Val2) return 0;
-  
-  // ICMP_[US][GL]E X, CST is folded to ICMP_[US][GL]T elsewhere.
-  if (LHSCC == ICmpInst::ICMP_UGE || LHSCC == ICmpInst::ICMP_ULE ||
-      RHSCC == ICmpInst::ICMP_UGE || RHSCC == ICmpInst::ICMP_ULE ||
-      LHSCC == ICmpInst::ICMP_SGE || LHSCC == ICmpInst::ICMP_SLE ||
-      RHSCC == ICmpInst::ICMP_SGE || RHSCC == ICmpInst::ICMP_SLE)
-    return 0;
-  
-  // We can't fold (ugt x, C) | (sgt x, C2).
-  if (!PredicatesFoldable(LHSCC, RHSCC))
-    return 0;
-  
-  // Ensure that the larger constant is on the RHS.
-  bool ShouldSwap;
-  if (CmpInst::isSigned(LHSCC) ||
-      (ICmpInst::isEquality(LHSCC) && 
-       CmpInst::isSigned(RHSCC)))
-    ShouldSwap = LHSCst->getValue().sgt(RHSCst->getValue());
-  else
-    ShouldSwap = LHSCst->getValue().ugt(RHSCst->getValue());
-  
-  if (ShouldSwap) {
-    std::swap(LHS, RHS);
-    std::swap(LHSCst, RHSCst);
-    std::swap(LHSCC, RHSCC);
-  }
-  
-  // At this point, we know we have have two icmp instructions
-  // comparing a value against two constants and or'ing the result
-  // together.  Because of the above check, we know that we only have
-  // ICMP_EQ, ICMP_NE, ICMP_LT, and ICMP_GT here. We also know (from the
-  // FoldICmpLogical check above), that the two constants are not
-  // equal.
-  assert(LHSCst != RHSCst && "Compares not folded above?");
-
-  switch (LHSCC) {
-  default: llvm_unreachable("Unknown integer condition code!");
-  case ICmpInst::ICMP_EQ:
-    switch (RHSCC) {
-    default: llvm_unreachable("Unknown integer condition code!");
-    case ICmpInst::ICMP_EQ:
-      if (LHSCst == SubOne(RHSCst)) {
-        // (X == 13 | X == 14) -> X-13 <u 2
-        Constant *AddCST = ConstantExpr::getNeg(LHSCst);
-        Value *Add = Builder->CreateAdd(Val, AddCST, Val->getName()+".off");
-        AddCST = ConstantExpr::getSub(AddOne(RHSCst), LHSCst);
-        return new ICmpInst(ICmpInst::ICMP_ULT, Add, AddCST);
-      }
-      break;                         // (X == 13 | X == 15) -> no change
-    case ICmpInst::ICMP_UGT:         // (X == 13 | X u> 14) -> no change
-    case ICmpInst::ICMP_SGT:         // (X == 13 | X s> 14) -> no change
-      break;
-    case ICmpInst::ICMP_NE:          // (X == 13 | X != 15) -> X != 15
-    case ICmpInst::ICMP_ULT:         // (X == 13 | X u< 15) -> X u< 15
-    case ICmpInst::ICMP_SLT:         // (X == 13 | X s< 15) -> X s< 15
-      return ReplaceInstUsesWith(I, RHS);
-    }
-    break;
-  case ICmpInst::ICMP_NE:
-    switch (RHSCC) {
-    default: llvm_unreachable("Unknown integer condition code!");
-    case ICmpInst::ICMP_EQ:          // (X != 13 | X == 15) -> X != 13
-    case ICmpInst::ICMP_UGT:         // (X != 13 | X u> 15) -> X != 13
-    case ICmpInst::ICMP_SGT:         // (X != 13 | X s> 15) -> X != 13
-      return ReplaceInstUsesWith(I, LHS);
-    case ICmpInst::ICMP_NE:          // (X != 13 | X != 15) -> true
-    case ICmpInst::ICMP_ULT:         // (X != 13 | X u< 15) -> true
-    case ICmpInst::ICMP_SLT:         // (X != 13 | X s< 15) -> true
-      return ReplaceInstUsesWith(I, ConstantInt::getTrue(*Context));
-    }
-    break;
-  case ICmpInst::ICMP_ULT:
-    switch (RHSCC) {
-    default: llvm_unreachable("Unknown integer condition code!");
-    case ICmpInst::ICMP_EQ:         // (X u< 13 | X == 14) -> no change
-      break;
-    case ICmpInst::ICMP_UGT:        // (X u< 13 | X u> 15) -> (X-13) u> 2
-      // If RHSCst is [us]MAXINT, it is always false.  Not handling
-      // this can cause overflow.
-      if (RHSCst->isMaxValue(false))
-        return ReplaceInstUsesWith(I, LHS);
-      return InsertRangeTest(Val, LHSCst, AddOne(RHSCst),
-                             false, false, I);
-    case ICmpInst::ICMP_SGT:        // (X u< 13 | X s> 15) -> no change
-      break;
-    case ICmpInst::ICMP_NE:         // (X u< 13 | X != 15) -> X != 15
-    case ICmpInst::ICMP_ULT:        // (X u< 13 | X u< 15) -> X u< 15
-      return ReplaceInstUsesWith(I, RHS);
-    case ICmpInst::ICMP_SLT:        // (X u< 13 | X s< 15) -> no change
-      break;
-    }
-    break;
-  case ICmpInst::ICMP_SLT:
-    switch (RHSCC) {
-    default: llvm_unreachable("Unknown integer condition code!");
-    case ICmpInst::ICMP_EQ:         // (X s< 13 | X == 14) -> no change
-      break;
-    case ICmpInst::ICMP_SGT:        // (X s< 13 | X s> 15) -> (X-13) s> 2
-      // If RHSCst is [us]MAXINT, it is always false.  Not handling
-      // this can cause overflow.
-      if (RHSCst->isMaxValue(true))
-        return ReplaceInstUsesWith(I, LHS);
-      return InsertRangeTest(Val, LHSCst, AddOne(RHSCst),
-                             true, false, I);
-    case ICmpInst::ICMP_UGT:        // (X s< 13 | X u> 15) -> no change
-      break;
-    case ICmpInst::ICMP_NE:         // (X s< 13 | X != 15) -> X != 15
-    case ICmpInst::ICMP_SLT:        // (X s< 13 | X s< 15) -> X s< 15
-      return ReplaceInstUsesWith(I, RHS);
-    case ICmpInst::ICMP_ULT:        // (X s< 13 | X u< 15) -> no change
-      break;
-    }
-    break;
-  case ICmpInst::ICMP_UGT:
-    switch (RHSCC) {
-    default: llvm_unreachable("Unknown integer condition code!");
-    case ICmpInst::ICMP_EQ:         // (X u> 13 | X == 15) -> X u> 13
-    case ICmpInst::ICMP_UGT:        // (X u> 13 | X u> 15) -> X u> 13
-      return ReplaceInstUsesWith(I, LHS);
-    case ICmpInst::ICMP_SGT:        // (X u> 13 | X s> 15) -> no change
-      break;
-    case ICmpInst::ICMP_NE:         // (X u> 13 | X != 15) -> true
-    case ICmpInst::ICMP_ULT:        // (X u> 13 | X u< 15) -> true
-      return ReplaceInstUsesWith(I, ConstantInt::getTrue(*Context));
-    case ICmpInst::ICMP_SLT:        // (X u> 13 | X s< 15) -> no change
-      break;
-    }
-    break;
-  case ICmpInst::ICMP_SGT:
-    switch (RHSCC) {
-    default: llvm_unreachable("Unknown integer condition code!");
-    case ICmpInst::ICMP_EQ:         // (X s> 13 | X == 15) -> X > 13
-    case ICmpInst::ICMP_SGT:        // (X s> 13 | X s> 15) -> X > 13
-      return ReplaceInstUsesWith(I, LHS);
-    case ICmpInst::ICMP_UGT:        // (X s> 13 | X u> 15) -> no change
-      break;
-    case ICmpInst::ICMP_NE:         // (X s> 13 | X != 15) -> true
-    case ICmpInst::ICMP_SLT:        // (X s> 13 | X s< 15) -> true
-      return ReplaceInstUsesWith(I, ConstantInt::getTrue(*Context));
-    case ICmpInst::ICMP_ULT:        // (X s> 13 | X u< 15) -> no change
-      break;
-    }
-    break;
-  }
-  return 0;
-}
-
-Instruction *InstCombiner::FoldOrOfFCmps(Instruction &I, FCmpInst *LHS,
-                                         FCmpInst *RHS) {
-  if (LHS->getPredicate() == FCmpInst::FCMP_UNO &&
-      RHS->getPredicate() == FCmpInst::FCMP_UNO && 
-      LHS->getOperand(0)->getType() == RHS->getOperand(0)->getType()) {
-    if (ConstantFP *LHSC = dyn_cast<ConstantFP>(LHS->getOperand(1)))
-      if (ConstantFP *RHSC = dyn_cast<ConstantFP>(RHS->getOperand(1))) {
-        // If either of the constants are nans, then the whole thing returns
-        // true.
-        if (LHSC->getValueAPF().isNaN() || RHSC->getValueAPF().isNaN())
-          return ReplaceInstUsesWith(I, ConstantInt::getTrue(*Context));
-        
-        // Otherwise, no need to compare the two constants, compare the
-        // rest.
-        return new FCmpInst(FCmpInst::FCMP_UNO,
-                            LHS->getOperand(0), RHS->getOperand(0));
-      }
-    
-    // Handle vector zeros.  This occurs because the canonical form of
-    // "fcmp uno x,x" is "fcmp uno x, 0".
-    if (isa<ConstantAggregateZero>(LHS->getOperand(1)) &&
-        isa<ConstantAggregateZero>(RHS->getOperand(1)))
-      return new FCmpInst(FCmpInst::FCMP_UNO,
-                          LHS->getOperand(0), RHS->getOperand(0));
-    
-    return 0;
-  }
-  
-  Value *Op0LHS = LHS->getOperand(0), *Op0RHS = LHS->getOperand(1);
-  Value *Op1LHS = RHS->getOperand(0), *Op1RHS = RHS->getOperand(1);
-  FCmpInst::Predicate Op0CC = LHS->getPredicate(), Op1CC = RHS->getPredicate();
-  
-  if (Op0LHS == Op1RHS && Op0RHS == Op1LHS) {
-    // Swap RHS operands to match LHS.
-    Op1CC = FCmpInst::getSwappedPredicate(Op1CC);
-    std::swap(Op1LHS, Op1RHS);
-  }
-  if (Op0LHS == Op1LHS && Op0RHS == Op1RHS) {
-    // Simplify (fcmp cc0 x, y) | (fcmp cc1 x, y).
-    if (Op0CC == Op1CC)
-      return new FCmpInst((FCmpInst::Predicate)Op0CC,
-                          Op0LHS, Op0RHS);
-    if (Op0CC == FCmpInst::FCMP_TRUE || Op1CC == FCmpInst::FCMP_TRUE)
-      return ReplaceInstUsesWith(I, ConstantInt::getTrue(*Context));
-    if (Op0CC == FCmpInst::FCMP_FALSE)
-      return ReplaceInstUsesWith(I, RHS);
-    if (Op1CC == FCmpInst::FCMP_FALSE)
-      return ReplaceInstUsesWith(I, LHS);
-    bool Op0Ordered;
-    bool Op1Ordered;
-    unsigned Op0Pred = getFCmpCode(Op0CC, Op0Ordered);
-    unsigned Op1Pred = getFCmpCode(Op1CC, Op1Ordered);
-    if (Op0Ordered == Op1Ordered) {
-      // If both are ordered or unordered, return a new fcmp with
-      // or'ed predicates.
-      Value *RV = getFCmpValue(Op0Ordered, Op0Pred|Op1Pred,
-                               Op0LHS, Op0RHS, Context);
-      if (Instruction *I = dyn_cast<Instruction>(RV))
-        return I;
-      // Otherwise, it's a constant boolean value...
-      return ReplaceInstUsesWith(I, RV);
-    }
-  }
-  return 0;
-}
-
-/// FoldOrWithConstants - This helper function folds:
-///
-///     ((A | B) & C1) | (B & C2)
-///
-/// into:
-/// 
-///     (A & C1) | B
-///
-/// when the XOR of the two constants is "all ones" (-1).
-Instruction *InstCombiner::FoldOrWithConstants(BinaryOperator &I, Value *Op,
-                                               Value *A, Value *B, Value *C) {
-  ConstantInt *CI1 = dyn_cast<ConstantInt>(C);
-  if (!CI1) return 0;
-
-  Value *V1 = 0;
-  ConstantInt *CI2 = 0;
-  if (!match(Op, m_And(m_Value(V1), m_ConstantInt(CI2)))) return 0;
-
-  APInt Xor = CI1->getValue() ^ CI2->getValue();
-  if (!Xor.isAllOnesValue()) return 0;
-
-  if (V1 == A || V1 == B) {
-    Value *NewOp = Builder->CreateAnd((V1 == A) ? B : A, CI1);
-    return BinaryOperator::CreateOr(NewOp, V1);
-  }
-
-  return 0;
-}
-
-Instruction *InstCombiner::visitOr(BinaryOperator &I) {
-  bool Changed = SimplifyCommutative(I);
-  Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
-  if (Value *V = SimplifyOrInst(Op0, Op1, TD))
-    return ReplaceInstUsesWith(I, V);
-  
-  
-  // See if we can simplify any instructions used by the instruction whose sole 
-  // purpose is to compute bits we don't care about.
-  if (SimplifyDemandedInstructionBits(I))
-    return &I;
-
-  if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
-    ConstantInt *C1 = 0; Value *X = 0;
-    // (X & C1) | C2 --> (X | C2) & (C1|C2)
-    if (match(Op0, m_And(m_Value(X), m_ConstantInt(C1))) &&
-        isOnlyUse(Op0)) {
-      Value *Or = Builder->CreateOr(X, RHS);
-      Or->takeName(Op0);
-      return BinaryOperator::CreateAnd(Or, 
-               ConstantInt::get(*Context, RHS->getValue() | C1->getValue()));
-    }
-
-    // (X ^ C1) | C2 --> (X | C2) ^ (C1&~C2)
-    if (match(Op0, m_Xor(m_Value(X), m_ConstantInt(C1))) &&
-        isOnlyUse(Op0)) {
-      Value *Or = Builder->CreateOr(X, RHS);
-      Or->takeName(Op0);
-      return BinaryOperator::CreateXor(Or,
-                 ConstantInt::get(*Context, C1->getValue() & ~RHS->getValue()));
-    }
-
-    // Try to fold constant and into select arguments.
-    if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
-      if (Instruction *R = FoldOpIntoSelect(I, SI, this))
-        return R;
-    if (isa<PHINode>(Op0))
-      if (Instruction *NV = FoldOpIntoPhi(I))
-        return NV;
-  }
-
-  Value *A = 0, *B = 0;
-  ConstantInt *C1 = 0, *C2 = 0;
-
-  // (A | B) | C  and  A | (B | C)                  -> bswap if possible.
-  // (A >> B) | (C << D)  and  (A << B) | (B >> C)  -> bswap if possible.
-  if (match(Op0, m_Or(m_Value(), m_Value())) ||
-      match(Op1, m_Or(m_Value(), m_Value())) ||
-      (match(Op0, m_Shift(m_Value(), m_Value())) &&
-       match(Op1, m_Shift(m_Value(), m_Value())))) {
-    if (Instruction *BSwap = MatchBSwap(I))
-      return BSwap;
-  }
-  
-  // (X^C)|Y -> (X|Y)^C iff Y&C == 0
-  if (Op0->hasOneUse() &&
-      match(Op0, m_Xor(m_Value(A), m_ConstantInt(C1))) &&
-      MaskedValueIsZero(Op1, C1->getValue())) {
-    Value *NOr = Builder->CreateOr(A, Op1);
-    NOr->takeName(Op0);
-    return BinaryOperator::CreateXor(NOr, C1);
-  }
-
-  // Y|(X^C) -> (X|Y)^C iff Y&C == 0
-  if (Op1->hasOneUse() &&
-      match(Op1, m_Xor(m_Value(A), m_ConstantInt(C1))) &&
-      MaskedValueIsZero(Op0, C1->getValue())) {
-    Value *NOr = Builder->CreateOr(A, Op0);
-    NOr->takeName(Op0);
-    return BinaryOperator::CreateXor(NOr, C1);
-  }
-
-  // (A & C)|(B & D)
-  Value *C = 0, *D = 0;
-  if (match(Op0, m_And(m_Value(A), m_Value(C))) &&
-      match(Op1, m_And(m_Value(B), m_Value(D)))) {
-    Value *V1 = 0, *V2 = 0, *V3 = 0;
-    C1 = dyn_cast<ConstantInt>(C);
-    C2 = dyn_cast<ConstantInt>(D);
-    if (C1 && C2) {  // (A & C1)|(B & C2)
-      // If we have: ((V + N) & C1) | (V & C2)
-      // .. and C2 = ~C1 and C2 is 0+1+ and (N & C2) == 0
-      // replace with V+N.
-      if (C1->getValue() == ~C2->getValue()) {
-        if ((C2->getValue() & (C2->getValue()+1)) == 0 && // C2 == 0+1+
-            match(A, m_Add(m_Value(V1), m_Value(V2)))) {
-          // Add commutes, try both ways.
-          if (V1 == B && MaskedValueIsZero(V2, C2->getValue()))
-            return ReplaceInstUsesWith(I, A);
-          if (V2 == B && MaskedValueIsZero(V1, C2->getValue()))
-            return ReplaceInstUsesWith(I, A);
-        }
-        // Or commutes, try both ways.
-        if ((C1->getValue() & (C1->getValue()+1)) == 0 &&
-            match(B, m_Add(m_Value(V1), m_Value(V2)))) {
-          // Add commutes, try both ways.
-          if (V1 == A && MaskedValueIsZero(V2, C1->getValue()))
-            return ReplaceInstUsesWith(I, B);
-          if (V2 == A && MaskedValueIsZero(V1, C1->getValue()))
-            return ReplaceInstUsesWith(I, B);
-        }
-      }
-      
-      // ((V | N) & C1) | (V & C2) --> (V|N) & (C1|C2)
-      // iff (C1&C2) == 0 and (N&~C1) == 0
-      if ((C1->getValue() & C2->getValue()) == 0) {
-        if (match(A, m_Or(m_Value(V1), m_Value(V2))) &&
-            ((V1 == B && MaskedValueIsZero(V2, ~C1->getValue())) ||  // (V|N)
-             (V2 == B && MaskedValueIsZero(V1, ~C1->getValue()))))   // (N|V)
-          return BinaryOperator::CreateAnd(A,
-                               ConstantInt::get(A->getContext(),
-                                                C1->getValue()|C2->getValue()));
-        // Or commutes, try both ways.
-        if (match(B, m_Or(m_Value(V1), m_Value(V2))) &&
-            ((V1 == A && MaskedValueIsZero(V2, ~C2->getValue())) ||  // (V|N)
-             (V2 == A && MaskedValueIsZero(V1, ~C2->getValue()))))   // (N|V)
-          return BinaryOperator::CreateAnd(B,
-                               ConstantInt::get(B->getContext(),
-                                                C1->getValue()|C2->getValue()));
-      }
-    }
-    
-    // Check to see if we have any common things being and'ed.  If so, find the
-    // terms for V1 & (V2|V3).
-    if (isOnlyUse(Op0) || isOnlyUse(Op1)) {
-      V1 = 0;
-      if (A == B)      // (A & C)|(A & D) == A & (C|D)
-        V1 = A, V2 = C, V3 = D;
-      else if (A == D) // (A & C)|(B & A) == A & (B|C)
-        V1 = A, V2 = B, V3 = C;
-      else if (C == B) // (A & C)|(C & D) == C & (A|D)
-        V1 = C, V2 = A, V3 = D;
-      else if (C == D) // (A & C)|(B & C) == C & (A|B)
-        V1 = C, V2 = A, V3 = B;
-      
-      if (V1) {
-        Value *Or = Builder->CreateOr(V2, V3, "tmp");
-        return BinaryOperator::CreateAnd(V1, Or);
-      }
-    }
-
-    // (A & (C0?-1:0)) | (B & ~(C0?-1:0)) ->  C0 ? A : B, and commuted variants
-    if (Instruction *Match = MatchSelectFromAndOr(A, B, C, D, Context))
-      return Match;
-    if (Instruction *Match = MatchSelectFromAndOr(B, A, D, C, Context))
-      return Match;
-    if (Instruction *Match = MatchSelectFromAndOr(C, B, A, D, Context))
-      return Match;
-    if (Instruction *Match = MatchSelectFromAndOr(D, A, B, C, Context))
-      return Match;
-
-    // ((A&~B)|(~A&B)) -> A^B
-    if ((match(C, m_Not(m_Specific(D))) &&
-         match(B, m_Not(m_Specific(A)))))
-      return BinaryOperator::CreateXor(A, D);
-    // ((~B&A)|(~A&B)) -> A^B
-    if ((match(A, m_Not(m_Specific(D))) &&
-         match(B, m_Not(m_Specific(C)))))
-      return BinaryOperator::CreateXor(C, D);
-    // ((A&~B)|(B&~A)) -> A^B
-    if ((match(C, m_Not(m_Specific(B))) &&
-         match(D, m_Not(m_Specific(A)))))
-      return BinaryOperator::CreateXor(A, B);
-    // ((~B&A)|(B&~A)) -> A^B
-    if ((match(A, m_Not(m_Specific(B))) &&
-         match(D, m_Not(m_Specific(C)))))
-      return BinaryOperator::CreateXor(C, B);
-  }
-  
-  // (X >> Z) | (Y >> Z)  -> (X|Y) >> Z  for all shifts.
-  if (BinaryOperator *SI1 = dyn_cast<BinaryOperator>(Op1)) {
-    if (BinaryOperator *SI0 = dyn_cast<BinaryOperator>(Op0))
-      if (SI0->isShift() && SI0->getOpcode() == SI1->getOpcode() && 
-          SI0->getOperand(1) == SI1->getOperand(1) &&
-          (SI0->hasOneUse() || SI1->hasOneUse())) {
-        Value *NewOp = Builder->CreateOr(SI0->getOperand(0), SI1->getOperand(0),
-                                         SI0->getName());
-        return BinaryOperator::Create(SI1->getOpcode(), NewOp, 
-                                      SI1->getOperand(1));
-      }
-  }
-
-  // ((A|B)&1)|(B&-2) -> (A&1) | B
-  if (match(Op0, m_And(m_Or(m_Value(A), m_Value(B)), m_Value(C))) ||
-      match(Op0, m_And(m_Value(C), m_Or(m_Value(A), m_Value(B))))) {
-    Instruction *Ret = FoldOrWithConstants(I, Op1, A, B, C);
-    if (Ret) return Ret;
-  }
-  // (B&-2)|((A|B)&1) -> (A&1) | B
-  if (match(Op1, m_And(m_Or(m_Value(A), m_Value(B)), m_Value(C))) ||
-      match(Op1, m_And(m_Value(C), m_Or(m_Value(A), m_Value(B))))) {
-    Instruction *Ret = FoldOrWithConstants(I, Op0, A, B, C);
-    if (Ret) return Ret;
-  }
-
-  // (~A | ~B) == (~(A & B)) - De Morgan's Law
-  if (Value *Op0NotVal = dyn_castNotVal(Op0))
-    if (Value *Op1NotVal = dyn_castNotVal(Op1))
-      if (Op0->hasOneUse() && Op1->hasOneUse()) {
-        Value *And = Builder->CreateAnd(Op0NotVal, Op1NotVal,
-                                        I.getName()+".demorgan");
-        return BinaryOperator::CreateNot(And);
-      }
-
-  // (icmp1 A, B) | (icmp2 A, B) --> (icmp3 A, B)
-  if (ICmpInst *RHS = dyn_cast<ICmpInst>(I.getOperand(1))) {
-    if (Instruction *R = AssociativeOpt(I, FoldICmpLogical(*this, RHS)))
-      return R;
-
-    if (ICmpInst *LHS = dyn_cast<ICmpInst>(I.getOperand(0)))
-      if (Instruction *Res = FoldOrOfICmps(I, LHS, RHS))
-        return Res;
-  }
-    
-  // fold (or (cast A), (cast B)) -> (cast (or A, B))
-  if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
-    if (CastInst *Op1C = dyn_cast<CastInst>(Op1))
-      if (Op0C->getOpcode() == Op1C->getOpcode()) {// same cast kind ?
-        if (!isa<ICmpInst>(Op0C->getOperand(0)) ||
-            !isa<ICmpInst>(Op1C->getOperand(0))) {
-          const Type *SrcTy = Op0C->getOperand(0)->getType();
-          if (SrcTy == Op1C->getOperand(0)->getType() &&
-              SrcTy->isIntOrIntVector() &&
-              // Only do this if the casts both really cause code to be
-              // generated.
-              ValueRequiresCast(Op0C->getOpcode(), Op0C->getOperand(0), 
-                                I.getType(), TD) &&
-              ValueRequiresCast(Op1C->getOpcode(), Op1C->getOperand(0), 
-                                I.getType(), TD)) {
-            Value *NewOp = Builder->CreateOr(Op0C->getOperand(0),
-                                             Op1C->getOperand(0), I.getName());
-            return CastInst::Create(Op0C->getOpcode(), NewOp, I.getType());
-          }
-        }
-      }
-  }
-  
-    
-  // (fcmp uno x, c) | (fcmp uno y, c)  -> (fcmp uno x, y)
-  if (FCmpInst *LHS = dyn_cast<FCmpInst>(I.getOperand(0))) {
-    if (FCmpInst *RHS = dyn_cast<FCmpInst>(I.getOperand(1)))
-      if (Instruction *Res = FoldOrOfFCmps(I, LHS, RHS))
-        return Res;
-  }
-
-  return Changed ? &I : 0;
-}
-
-namespace {
-
-// XorSelf - Implements: X ^ X --> 0
-struct XorSelf {
-  Value *RHS;
-  XorSelf(Value *rhs) : RHS(rhs) {}
-  bool shouldApply(Value *LHS) const { return LHS == RHS; }
-  Instruction *apply(BinaryOperator &Xor) const {
-    return &Xor;
-  }
-};
-
-}
-
-Instruction *InstCombiner::visitXor(BinaryOperator &I) {
-  bool Changed = SimplifyCommutative(I);
-  Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
-  if (isa<UndefValue>(Op1)) {
-    if (isa<UndefValue>(Op0))
-      // Handle undef ^ undef -> 0 special case. This is a common
-      // idiom (misuse).
-      return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
-    return ReplaceInstUsesWith(I, Op1);  // X ^ undef -> undef
-  }
-
-  // xor X, X = 0, even if X is nested in a sequence of Xor's.
-  if (Instruction *Result = AssociativeOpt(I, XorSelf(Op1))) {
-    assert(Result == &I && "AssociativeOpt didn't work?"); Result=Result;
-    return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
-  }
-  
-  // See if we can simplify any instructions used by the instruction whose sole 
-  // purpose is to compute bits we don't care about.
-  if (SimplifyDemandedInstructionBits(I))
-    return &I;
-  if (isa<VectorType>(I.getType()))
-    if (isa<ConstantAggregateZero>(Op1))
-      return ReplaceInstUsesWith(I, Op0);  // X ^ <0,0> -> X
-
-  // Is this a ~ operation?
-  if (Value *NotOp = dyn_castNotVal(&I)) {
-    if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(NotOp)) {
-      if (Op0I->getOpcode() == Instruction::And || 
-          Op0I->getOpcode() == Instruction::Or) {
-        // ~(~X & Y) --> (X | ~Y) - De Morgan's Law
-        // ~(~X | Y) === (X & ~Y) - De Morgan's Law
-        if (dyn_castNotVal(Op0I->getOperand(1)))
-          Op0I->swapOperands();
-        if (Value *Op0NotVal = dyn_castNotVal(Op0I->getOperand(0))) {
-          Value *NotY =
-            Builder->CreateNot(Op0I->getOperand(1),
-                               Op0I->getOperand(1)->getName()+".not");
-          if (Op0I->getOpcode() == Instruction::And)
-            return BinaryOperator::CreateOr(Op0NotVal, NotY);
-          return BinaryOperator::CreateAnd(Op0NotVal, NotY);
-        }
-        
-        // ~(X & Y) --> (~X | ~Y) - De Morgan's Law
-        // ~(X | Y) === (~X & ~Y) - De Morgan's Law
-        if (isFreeToInvert(Op0I->getOperand(0)) && 
-            isFreeToInvert(Op0I->getOperand(1))) {
-          Value *NotX =
-            Builder->CreateNot(Op0I->getOperand(0), "notlhs");
-          Value *NotY =
-            Builder->CreateNot(Op0I->getOperand(1), "notrhs");
-          if (Op0I->getOpcode() == Instruction::And)
-            return BinaryOperator::CreateOr(NotX, NotY);
-          return BinaryOperator::CreateAnd(NotX, NotY);
-        }
-      }
-    }
-  }
-  
-  
-  if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
-    if (RHS->isOne() && Op0->hasOneUse()) {
-      // xor (cmp A, B), true = not (cmp A, B) = !cmp A, B
-      if (ICmpInst *ICI = dyn_cast<ICmpInst>(Op0))
-        return new ICmpInst(ICI->getInversePredicate(),
-                            ICI->getOperand(0), ICI->getOperand(1));
-
-      if (FCmpInst *FCI = dyn_cast<FCmpInst>(Op0))
-        return new FCmpInst(FCI->getInversePredicate(),
-                            FCI->getOperand(0), FCI->getOperand(1));
-    }
-
-    // fold (xor(zext(cmp)), 1) and (xor(sext(cmp)), -1) to ext(!cmp).
-    if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
-      if (CmpInst *CI = dyn_cast<CmpInst>(Op0C->getOperand(0))) {
-        if (CI->hasOneUse() && Op0C->hasOneUse()) {
-          Instruction::CastOps Opcode = Op0C->getOpcode();
-          if ((Opcode == Instruction::ZExt || Opcode == Instruction::SExt) &&
-              (RHS == ConstantExpr::getCast(Opcode, 
-                                            ConstantInt::getTrue(*Context),
-                                            Op0C->getDestTy()))) {
-            CI->setPredicate(CI->getInversePredicate());
-            return CastInst::Create(Opcode, CI, Op0C->getType());
-          }
-        }
-      }
-    }
-
-    if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) {
-      // ~(c-X) == X-c-1 == X+(-c-1)
-      if (Op0I->getOpcode() == Instruction::Sub && RHS->isAllOnesValue())
-        if (Constant *Op0I0C = dyn_cast<Constant>(Op0I->getOperand(0))) {
-          Constant *NegOp0I0C = ConstantExpr::getNeg(Op0I0C);
-          Constant *ConstantRHS = ConstantExpr::getSub(NegOp0I0C,
-                                      ConstantInt::get(I.getType(), 1));
-          return BinaryOperator::CreateAdd(Op0I->getOperand(1), ConstantRHS);
-        }
-          
-      if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1))) {
-        if (Op0I->getOpcode() == Instruction::Add) {
-          // ~(X-c) --> (-c-1)-X
-          if (RHS->isAllOnesValue()) {
-            Constant *NegOp0CI = ConstantExpr::getNeg(Op0CI);
-            return BinaryOperator::CreateSub(
-                           ConstantExpr::getSub(NegOp0CI,
-                                      ConstantInt::get(I.getType(), 1)),
-                                      Op0I->getOperand(0));
-          } else if (RHS->getValue().isSignBit()) {
-            // (X + C) ^ signbit -> (X + C + signbit)
-            Constant *C = ConstantInt::get(*Context,
-                                           RHS->getValue() + Op0CI->getValue());
-            return BinaryOperator::CreateAdd(Op0I->getOperand(0), C);
-
-          }
-        } else if (Op0I->getOpcode() == Instruction::Or) {
-          // (X|C1)^C2 -> X^(C1|C2) iff X&~C1 == 0
-          if (MaskedValueIsZero(Op0I->getOperand(0), Op0CI->getValue())) {
-            Constant *NewRHS = ConstantExpr::getOr(Op0CI, RHS);
-            // Anything in both C1 and C2 is known to be zero, remove it from
-            // NewRHS.
-            Constant *CommonBits = ConstantExpr::getAnd(Op0CI, RHS);
-            NewRHS = ConstantExpr::getAnd(NewRHS, 
-                                       ConstantExpr::getNot(CommonBits));
-            Worklist.Add(Op0I);
-            I.setOperand(0, Op0I->getOperand(0));
-            I.setOperand(1, NewRHS);
-            return &I;
-          }
-        }
-      }
-    }
-
-    // Try to fold constant and into select arguments.
-    if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
-      if (Instruction *R = FoldOpIntoSelect(I, SI, this))
-        return R;
-    if (isa<PHINode>(Op0))
-      if (Instruction *NV = FoldOpIntoPhi(I))
-        return NV;
-  }
-
-  if (Value *X = dyn_castNotVal(Op0))   // ~A ^ A == -1
-    if (X == Op1)
-      return ReplaceInstUsesWith(I, Constant::getAllOnesValue(I.getType()));
-
-  if (Value *X = dyn_castNotVal(Op1))   // A ^ ~A == -1
-    if (X == Op0)
-      return ReplaceInstUsesWith(I, Constant::getAllOnesValue(I.getType()));
-
-  
-  BinaryOperator *Op1I = dyn_cast<BinaryOperator>(Op1);
-  if (Op1I) {
-    Value *A, *B;
-    if (match(Op1I, m_Or(m_Value(A), m_Value(B)))) {
-      if (A == Op0) {              // B^(B|A) == (A|B)^B
-        Op1I->swapOperands();
-        I.swapOperands();
-        std::swap(Op0, Op1);
-      } else if (B == Op0) {       // B^(A|B) == (A|B)^B
-        I.swapOperands();     // Simplified below.
-        std::swap(Op0, Op1);
-      }
-    } else if (match(Op1I, m_Xor(m_Specific(Op0), m_Value(B)))) {
-      return ReplaceInstUsesWith(I, B);                      // A^(A^B) == B
-    } else if (match(Op1I, m_Xor(m_Value(A), m_Specific(Op0)))) {
-      return ReplaceInstUsesWith(I, A);                      // A^(B^A) == B
-    } else if (match(Op1I, m_And(m_Value(A), m_Value(B))) && 
-               Op1I->hasOneUse()){
-      if (A == Op0) {                                      // A^(A&B) -> A^(B&A)
-        Op1I->swapOperands();
-        std::swap(A, B);
-      }
-      if (B == Op0) {                                      // A^(B&A) -> (B&A)^A
-        I.swapOperands();     // Simplified below.
-        std::swap(Op0, Op1);
-      }
-    }
-  }
-  
-  BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0);
-  if (Op0I) {
-    Value *A, *B;
-    if (match(Op0I, m_Or(m_Value(A), m_Value(B))) &&
-        Op0I->hasOneUse()) {
-      if (A == Op1)                                  // (B|A)^B == (A|B)^B
-        std::swap(A, B);
-      if (B == Op1)                                  // (A|B)^B == A & ~B
-        return BinaryOperator::CreateAnd(A, Builder->CreateNot(Op1, "tmp"));
-    } else if (match(Op0I, m_Xor(m_Specific(Op1), m_Value(B)))) {
-      return ReplaceInstUsesWith(I, B);                      // (A^B)^A == B
-    } else if (match(Op0I, m_Xor(m_Value(A), m_Specific(Op1)))) {
-      return ReplaceInstUsesWith(I, A);                      // (B^A)^A == B
-    } else if (match(Op0I, m_And(m_Value(A), m_Value(B))) && 
-               Op0I->hasOneUse()){
-      if (A == Op1)                                        // (A&B)^A -> (B&A)^A
-        std::swap(A, B);
-      if (B == Op1 &&                                      // (B&A)^A == ~B & A
-          !isa<ConstantInt>(Op1)) {  // Canonical form is (B&C)^C
-        return BinaryOperator::CreateAnd(Builder->CreateNot(A, "tmp"), Op1);
-      }
-    }
-  }
-  
-  // (X >> Z) ^ (Y >> Z)  -> (X^Y) >> Z  for all shifts.
-  if (Op0I && Op1I && Op0I->isShift() && 
-      Op0I->getOpcode() == Op1I->getOpcode() && 
-      Op0I->getOperand(1) == Op1I->getOperand(1) &&
-      (Op1I->hasOneUse() || Op1I->hasOneUse())) {
-    Value *NewOp =
-      Builder->CreateXor(Op0I->getOperand(0), Op1I->getOperand(0),
-                         Op0I->getName());
-    return BinaryOperator::Create(Op1I->getOpcode(), NewOp, 
-                                  Op1I->getOperand(1));
-  }
-    
-  if (Op0I && Op1I) {
-    Value *A, *B, *C, *D;
-    // (A & B)^(A | B) -> A ^ B
-    if (match(Op0I, m_And(m_Value(A), m_Value(B))) &&
-        match(Op1I, m_Or(m_Value(C), m_Value(D)))) {
-      if ((A == C && B == D) || (A == D && B == C)) 
-        return BinaryOperator::CreateXor(A, B);
-    }
-    // (A | B)^(A & B) -> A ^ B
-    if (match(Op0I, m_Or(m_Value(A), m_Value(B))) &&
-        match(Op1I, m_And(m_Value(C), m_Value(D)))) {
-      if ((A == C && B == D) || (A == D && B == C)) 
-        return BinaryOperator::CreateXor(A, B);
-    }
-    
-    // (A & B)^(C & D)
-    if ((Op0I->hasOneUse() || Op1I->hasOneUse()) &&
-        match(Op0I, m_And(m_Value(A), m_Value(B))) &&
-        match(Op1I, m_And(m_Value(C), m_Value(D)))) {
-      // (X & Y)^(X & Y) -> (Y^Z) & X
-      Value *X = 0, *Y = 0, *Z = 0;
-      if (A == C)
-        X = A, Y = B, Z = D;
-      else if (A == D)
-        X = A, Y = B, Z = C;
-      else if (B == C)
-        X = B, Y = A, Z = D;
-      else if (B == D)
-        X = B, Y = A, Z = C;
-      
-      if (X) {
-        Value *NewOp = Builder->CreateXor(Y, Z, Op0->getName());
-        return BinaryOperator::CreateAnd(NewOp, X);
-      }
-    }
-  }
-    
-  // (icmp1 A, B) ^ (icmp2 A, B) --> (icmp3 A, B)
-  if (ICmpInst *RHS = dyn_cast<ICmpInst>(I.getOperand(1)))
-    if (Instruction *R = AssociativeOpt(I, FoldICmpLogical(*this, RHS)))
-      return R;
-
-  // fold (xor (cast A), (cast B)) -> (cast (xor A, B))
-  if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
-    if (CastInst *Op1C = dyn_cast<CastInst>(Op1))
-      if (Op0C->getOpcode() == Op1C->getOpcode()) { // same cast kind?
-        const Type *SrcTy = Op0C->getOperand(0)->getType();
-        if (SrcTy == Op1C->getOperand(0)->getType() && SrcTy->isInteger() &&
-            // Only do this if the casts both really cause code to be generated.
-            ValueRequiresCast(Op0C->getOpcode(), Op0C->getOperand(0), 
-                              I.getType(), TD) &&
-            ValueRequiresCast(Op1C->getOpcode(), Op1C->getOperand(0), 
-                              I.getType(), TD)) {
-          Value *NewOp = Builder->CreateXor(Op0C->getOperand(0),
-                                            Op1C->getOperand(0), I.getName());
-          return CastInst::Create(Op0C->getOpcode(), NewOp, I.getType());
-        }
-      }
-  }
-
-  return Changed ? &I : 0;
-}
-
-static ConstantInt *ExtractElement(Constant *V, Constant *Idx,
-                                   LLVMContext *Context) {
-  return cast<ConstantInt>(ConstantExpr::getExtractElement(V, Idx));
-}
-
-static bool HasAddOverflow(ConstantInt *Result,
-                           ConstantInt *In1, ConstantInt *In2,
-                           bool IsSigned) {
-  if (IsSigned)
-    if (In2->getValue().isNegative())
-      return Result->getValue().sgt(In1->getValue());
-    else
-      return Result->getValue().slt(In1->getValue());
-  else
-    return Result->getValue().ult(In1->getValue());
-}
-
-/// AddWithOverflow - Compute Result = In1+In2, returning true if the result
-/// overflowed for this type.
-static bool AddWithOverflow(Constant *&Result, Constant *In1,
-                            Constant *In2, LLVMContext *Context,
-                            bool IsSigned = false) {
-  Result = ConstantExpr::getAdd(In1, In2);
-
-  if (const VectorType *VTy = dyn_cast<VectorType>(In1->getType())) {
-    for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
-      Constant *Idx = ConstantInt::get(Type::getInt32Ty(*Context), i);
-      if (HasAddOverflow(ExtractElement(Result, Idx, Context),
-                         ExtractElement(In1, Idx, Context),
-                         ExtractElement(In2, Idx, Context),
-                         IsSigned))
-        return true;
-    }
-    return false;
-  }
-
-  return HasAddOverflow(cast<ConstantInt>(Result),
-                        cast<ConstantInt>(In1), cast<ConstantInt>(In2),
-                        IsSigned);
-}
-
-static bool HasSubOverflow(ConstantInt *Result,
-                           ConstantInt *In1, ConstantInt *In2,
-                           bool IsSigned) {
-  if (IsSigned)
-    if (In2->getValue().isNegative())
-      return Result->getValue().slt(In1->getValue());
-    else
-      return Result->getValue().sgt(In1->getValue());
-  else
-    return Result->getValue().ugt(In1->getValue());
-}
-
-/// SubWithOverflow - Compute Result = In1-In2, returning true if the result
-/// overflowed for this type.
-static bool SubWithOverflow(Constant *&Result, Constant *In1,
-                            Constant *In2, LLVMContext *Context,
-                            bool IsSigned = false) {
-  Result = ConstantExpr::getSub(In1, In2);
-
-  if (const VectorType *VTy = dyn_cast<VectorType>(In1->getType())) {
-    for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
-      Constant *Idx = ConstantInt::get(Type::getInt32Ty(*Context), i);
-      if (HasSubOverflow(ExtractElement(Result, Idx, Context),
-                         ExtractElement(In1, Idx, Context),
-                         ExtractElement(In2, Idx, Context),
-                         IsSigned))
-        return true;
-    }
-    return false;
-  }
-
-  return HasSubOverflow(cast<ConstantInt>(Result),
-                        cast<ConstantInt>(In1), cast<ConstantInt>(In2),
-                        IsSigned);
-}
-
-
-/// FoldGEPICmp - Fold comparisons between a GEP instruction and something
-/// else.  At this point we know that the GEP is on the LHS of the comparison.
-Instruction *InstCombiner::FoldGEPICmp(GEPOperator *GEPLHS, Value *RHS,
-                                       ICmpInst::Predicate Cond,
-                                       Instruction &I) {
-  // Look through bitcasts.
-  if (BitCastInst *BCI = dyn_cast<BitCastInst>(RHS))
-    RHS = BCI->getOperand(0);
-
-  Value *PtrBase = GEPLHS->getOperand(0);
-  if (TD && PtrBase == RHS && GEPLHS->isInBounds()) {
-    // ((gep Ptr, OFFSET) cmp Ptr)   ---> (OFFSET cmp 0).
-    // This transformation (ignoring the base and scales) is valid because we
-    // know pointers can't overflow since the gep is inbounds.  See if we can
-    // output an optimized form.
-    Value *Offset = EvaluateGEPOffsetExpression(GEPLHS, I, *this);
-    
-    // If not, synthesize the offset the hard way.
-    if (Offset == 0)
-      Offset = EmitGEPOffset(GEPLHS, *this);
-    return new ICmpInst(ICmpInst::getSignedPredicate(Cond), Offset,
-                        Constant::getNullValue(Offset->getType()));
-  } else if (GEPOperator *GEPRHS = dyn_cast<GEPOperator>(RHS)) {
-    // If the base pointers are different, but the indices are the same, just
-    // compare the base pointer.
-    if (PtrBase != GEPRHS->getOperand(0)) {
-      bool IndicesTheSame = GEPLHS->getNumOperands()==GEPRHS->getNumOperands();
-      IndicesTheSame &= GEPLHS->getOperand(0)->getType() ==
-                        GEPRHS->getOperand(0)->getType();
-      if (IndicesTheSame)
-        for (unsigned i = 1, e = GEPLHS->getNumOperands(); i != e; ++i)
-          if (GEPLHS->getOperand(i) != GEPRHS->getOperand(i)) {
-            IndicesTheSame = false;
-            break;
-          }
-
-      // If all indices are the same, just compare the base pointers.
-      if (IndicesTheSame)
-        return new ICmpInst(ICmpInst::getSignedPredicate(Cond),
-                            GEPLHS->getOperand(0), GEPRHS->getOperand(0));
-
-      // Otherwise, the base pointers are different and the indices are
-      // different, bail out.
-      return 0;
-    }
-
-    // If one of the GEPs has all zero indices, recurse.
-    bool AllZeros = true;
-    for (unsigned i = 1, e = GEPLHS->getNumOperands(); i != e; ++i)
-      if (!isa<Constant>(GEPLHS->getOperand(i)) ||
-          !cast<Constant>(GEPLHS->getOperand(i))->isNullValue()) {
-        AllZeros = false;
-        break;
-      }
-    if (AllZeros)
-      return FoldGEPICmp(GEPRHS, GEPLHS->getOperand(0),
-                          ICmpInst::getSwappedPredicate(Cond), I);
-
-    // If the other GEP has all zero indices, recurse.
-    AllZeros = true;
-    for (unsigned i = 1, e = GEPRHS->getNumOperands(); i != e; ++i)
-      if (!isa<Constant>(GEPRHS->getOperand(i)) ||
-          !cast<Constant>(GEPRHS->getOperand(i))->isNullValue()) {
-        AllZeros = false;
-        break;
-      }
-    if (AllZeros)
-      return FoldGEPICmp(GEPLHS, GEPRHS->getOperand(0), Cond, I);
-
-    if (GEPLHS->getNumOperands() == GEPRHS->getNumOperands()) {
-      // If the GEPs only differ by one index, compare it.
-      unsigned NumDifferences = 0;  // Keep track of # differences.
-      unsigned DiffOperand = 0;     // The operand that differs.
-      for (unsigned i = 1, e = GEPRHS->getNumOperands(); i != e; ++i)
-        if (GEPLHS->getOperand(i) != GEPRHS->getOperand(i)) {
-          if (GEPLHS->getOperand(i)->getType()->getPrimitiveSizeInBits() !=
-                   GEPRHS->getOperand(i)->getType()->getPrimitiveSizeInBits()) {
-            // Irreconcilable differences.
-            NumDifferences = 2;
-            break;
-          } else {
-            if (NumDifferences++) break;
-            DiffOperand = i;
-          }
-        }
-
-      if (NumDifferences == 0)   // SAME GEP?
-        return ReplaceInstUsesWith(I, // No comparison is needed here.
-                                   ConstantInt::get(Type::getInt1Ty(*Context),
-                                             ICmpInst::isTrueWhenEqual(Cond)));
-
-      else if (NumDifferences == 1) {
-        Value *LHSV = GEPLHS->getOperand(DiffOperand);
-        Value *RHSV = GEPRHS->getOperand(DiffOperand);
-        // Make sure we do a signed comparison here.
-        return new ICmpInst(ICmpInst::getSignedPredicate(Cond), LHSV, RHSV);
-      }
-    }
-
-    // Only lower this if the icmp is the only user of the GEP or if we expect
-    // the result to fold to a constant!
-    if (TD &&
-        (isa<ConstantExpr>(GEPLHS) || GEPLHS->hasOneUse()) &&
-        (isa<ConstantExpr>(GEPRHS) || GEPRHS->hasOneUse())) {
-      // ((gep Ptr, OFFSET1) cmp (gep Ptr, OFFSET2)  --->  (OFFSET1 cmp OFFSET2)
-      Value *L = EmitGEPOffset(GEPLHS, *this);
-      Value *R = EmitGEPOffset(GEPRHS, *this);
-      return new ICmpInst(ICmpInst::getSignedPredicate(Cond), L, R);
-    }
-  }
-  return 0;
-}
-
-/// FoldFCmp_IntToFP_Cst - Fold fcmp ([us]itofp x, cst) if possible.
-///
-Instruction *InstCombiner::FoldFCmp_IntToFP_Cst(FCmpInst &I,
-                                                Instruction *LHSI,
-                                                Constant *RHSC) {
-  if (!isa<ConstantFP>(RHSC)) return 0;
-  const APFloat &RHS = cast<ConstantFP>(RHSC)->getValueAPF();
-  
-  // Get the width of the mantissa.  We don't want to hack on conversions that
-  // might lose information from the integer, e.g. "i64 -> float"
-  int MantissaWidth = LHSI->getType()->getFPMantissaWidth();
-  if (MantissaWidth == -1) return 0;  // Unknown.
-  
-  // Check to see that the input is converted from an integer type that is small
-  // enough that preserves all bits.  TODO: check here for "known" sign bits.
-  // This would allow us to handle (fptosi (x >>s 62) to float) if x is i64 f.e.
-  unsigned InputSize = LHSI->getOperand(0)->getType()->getScalarSizeInBits();
-  
-  // If this is a uitofp instruction, we need an extra bit to hold the sign.
-  bool LHSUnsigned = isa<UIToFPInst>(LHSI);
-  if (LHSUnsigned)
-    ++InputSize;
-  
-  // If the conversion would lose info, don't hack on this.
-  if ((int)InputSize > MantissaWidth)
-    return 0;
-  
-  // Otherwise, we can potentially simplify the comparison.  We know that it
-  // will always come through as an integer value and we know the constant is
-  // not a NAN (it would have been previously simplified).
-  assert(!RHS.isNaN() && "NaN comparison not already folded!");
-  
-  ICmpInst::Predicate Pred;
-  switch (I.getPredicate()) {
-  default: llvm_unreachable("Unexpected predicate!");
-  case FCmpInst::FCMP_UEQ:
-  case FCmpInst::FCMP_OEQ:
-    Pred = ICmpInst::ICMP_EQ;
-    break;
-  case FCmpInst::FCMP_UGT:
-  case FCmpInst::FCMP_OGT:
-    Pred = LHSUnsigned ? ICmpInst::ICMP_UGT : ICmpInst::ICMP_SGT;
-    break;
-  case FCmpInst::FCMP_UGE:
-  case FCmpInst::FCMP_OGE:
-    Pred = LHSUnsigned ? ICmpInst::ICMP_UGE : ICmpInst::ICMP_SGE;
-    break;
-  case FCmpInst::FCMP_ULT:
-  case FCmpInst::FCMP_OLT:
-    Pred = LHSUnsigned ? ICmpInst::ICMP_ULT : ICmpInst::ICMP_SLT;
-    break;
-  case FCmpInst::FCMP_ULE:
-  case FCmpInst::FCMP_OLE:
-    Pred = LHSUnsigned ? ICmpInst::ICMP_ULE : ICmpInst::ICMP_SLE;
-    break;
-  case FCmpInst::FCMP_UNE:
-  case FCmpInst::FCMP_ONE:
-    Pred = ICmpInst::ICMP_NE;
-    break;
-  case FCmpInst::FCMP_ORD:
-    return ReplaceInstUsesWith(I, ConstantInt::getTrue(*Context));
-  case FCmpInst::FCMP_UNO:
-    return ReplaceInstUsesWith(I, ConstantInt::getFalse(*Context));
-  }
-  
-  const IntegerType *IntTy = cast<IntegerType>(LHSI->getOperand(0)->getType());
-  
-  // Now we know that the APFloat is a normal number, zero or inf.
-  
-  // See if the FP constant is too large for the integer.  For example,
-  // comparing an i8 to 300.0.
-  unsigned IntWidth = IntTy->getScalarSizeInBits();
-  
-  if (!LHSUnsigned) {
-    // If the RHS value is > SignedMax, fold the comparison.  This handles +INF
-    // and large values.
-    APFloat SMax(RHS.getSemantics(), APFloat::fcZero, false);
-    SMax.convertFromAPInt(APInt::getSignedMaxValue(IntWidth), true,
-                          APFloat::rmNearestTiesToEven);
-    if (SMax.compare(RHS) == APFloat::cmpLessThan) {  // smax < 13123.0
-      if (Pred == ICmpInst::ICMP_NE  || Pred == ICmpInst::ICMP_SLT ||
-          Pred == ICmpInst::ICMP_SLE)
-        return ReplaceInstUsesWith(I, ConstantInt::getTrue(*Context));
-      return ReplaceInstUsesWith(I, ConstantInt::getFalse(*Context));
-    }
-  } else {
-    // If the RHS value is > UnsignedMax, fold the comparison. This handles
-    // +INF and large values.
-    APFloat UMax(RHS.getSemantics(), APFloat::fcZero, false);
-    UMax.convertFromAPInt(APInt::getMaxValue(IntWidth), false,
-                          APFloat::rmNearestTiesToEven);
-    if (UMax.compare(RHS) == APFloat::cmpLessThan) {  // umax < 13123.0
-      if (Pred == ICmpInst::ICMP_NE  || Pred == ICmpInst::ICMP_ULT ||
-          Pred == ICmpInst::ICMP_ULE)
-        return ReplaceInstUsesWith(I, ConstantInt::getTrue(*Context));
-      return ReplaceInstUsesWith(I, ConstantInt::getFalse(*Context));
-    }
-  }
-  
-  if (!LHSUnsigned) {
-    // See if the RHS value is < SignedMin.
-    APFloat SMin(RHS.getSemantics(), APFloat::fcZero, false);
-    SMin.convertFromAPInt(APInt::getSignedMinValue(IntWidth), true,
-                          APFloat::rmNearestTiesToEven);
-    if (SMin.compare(RHS) == APFloat::cmpGreaterThan) { // smin > 12312.0
-      if (Pred == ICmpInst::ICMP_NE || Pred == ICmpInst::ICMP_SGT ||
-          Pred == ICmpInst::ICMP_SGE)
-        return ReplaceInstUsesWith(I, ConstantInt::getTrue(*Context));
-      return ReplaceInstUsesWith(I, ConstantInt::getFalse(*Context));
-    }
-  }
-
-  // Okay, now we know that the FP constant fits in the range [SMIN, SMAX] or
-  // [0, UMAX], but it may still be fractional.  See if it is fractional by
-  // casting the FP value to the integer value and back, checking for equality.
-  // Don't do this for zero, because -0.0 is not fractional.
-  Constant *RHSInt = LHSUnsigned
-    ? ConstantExpr::getFPToUI(RHSC, IntTy)
-    : ConstantExpr::getFPToSI(RHSC, IntTy);
-  if (!RHS.isZero()) {
-    bool Equal = LHSUnsigned
-      ? ConstantExpr::getUIToFP(RHSInt, RHSC->getType()) == RHSC
-      : ConstantExpr::getSIToFP(RHSInt, RHSC->getType()) == RHSC;
-    if (!Equal) {
-      // If we had a comparison against a fractional value, we have to adjust
-      // the compare predicate and sometimes the value.  RHSC is rounded towards
-      // zero at this point.
-      switch (Pred) {
-      default: llvm_unreachable("Unexpected integer comparison!");
-      case ICmpInst::ICMP_NE:  // (float)int != 4.4   --> true
-        return ReplaceInstUsesWith(I, ConstantInt::getTrue(*Context));
-      case ICmpInst::ICMP_EQ:  // (float)int == 4.4   --> false
-        return ReplaceInstUsesWith(I, ConstantInt::getFalse(*Context));
-      case ICmpInst::ICMP_ULE:
-        // (float)int <= 4.4   --> int <= 4
-        // (float)int <= -4.4  --> false
-        if (RHS.isNegative())
-          return ReplaceInstUsesWith(I, ConstantInt::getFalse(*Context));
-        break;
-      case ICmpInst::ICMP_SLE:
-        // (float)int <= 4.4   --> int <= 4
-        // (float)int <= -4.4  --> int < -4
-        if (RHS.isNegative())
-          Pred = ICmpInst::ICMP_SLT;
-        break;
-      case ICmpInst::ICMP_ULT:
-        // (float)int < -4.4   --> false
-        // (float)int < 4.4    --> int <= 4
-        if (RHS.isNegative())
-          return ReplaceInstUsesWith(I, ConstantInt::getFalse(*Context));
-        Pred = ICmpInst::ICMP_ULE;
-        break;
-      case ICmpInst::ICMP_SLT:
-        // (float)int < -4.4   --> int < -4
-        // (float)int < 4.4    --> int <= 4
-        if (!RHS.isNegative())
-          Pred = ICmpInst::ICMP_SLE;
-        break;
-      case ICmpInst::ICMP_UGT:
-        // (float)int > 4.4    --> int > 4
-        // (float)int > -4.4   --> true
-        if (RHS.isNegative())
-          return ReplaceInstUsesWith(I, ConstantInt::getTrue(*Context));
-        break;
-      case ICmpInst::ICMP_SGT:
-        // (float)int > 4.4    --> int > 4
-        // (float)int > -4.4   --> int >= -4
-        if (RHS.isNegative())
-          Pred = ICmpInst::ICMP_SGE;
-        break;
-      case ICmpInst::ICMP_UGE:
-        // (float)int >= -4.4   --> true
-        // (float)int >= 4.4    --> int > 4
-        if (!RHS.isNegative())
-          return ReplaceInstUsesWith(I, ConstantInt::getTrue(*Context));
-        Pred = ICmpInst::ICMP_UGT;
-        break;
-      case ICmpInst::ICMP_SGE:
-        // (float)int >= -4.4   --> int >= -4
-        // (float)int >= 4.4    --> int > 4
-        if (!RHS.isNegative())
-          Pred = ICmpInst::ICMP_SGT;
-        break;
-      }
-    }
-  }
-
-  // Lower this FP comparison into an appropriate integer version of the
-  // comparison.
-  return new ICmpInst(Pred, LHSI->getOperand(0), RHSInt);
-}
-
-/// FoldCmpLoadFromIndexedGlobal - Called we see this pattern:
-///   cmp pred (load (gep GV, ...)), cmpcst
-/// where GV is a global variable with a constant initializer.  Try to simplify
-/// this into some simple computation that does not need the load.  For example
-/// we can optimize "icmp eq (load (gep "foo", 0, i)), 0" into "icmp eq i, 3".
-///
-/// If AndCst is non-null, then the loaded value is masked with that constant
-/// before doing the comparison.  This handles cases like "A[i]&4 == 0".
-Instruction *InstCombiner::
-FoldCmpLoadFromIndexedGlobal(GetElementPtrInst *GEP, GlobalVariable *GV,
-                             CmpInst &ICI, ConstantInt *AndCst) {
-  ConstantArray *Init = dyn_cast<ConstantArray>(GV->getInitializer());
-  if (Init == 0 || Init->getNumOperands() > 1024) return 0;
-  
-  // There are many forms of this optimization we can handle, for now, just do
-  // the simple index into a single-dimensional array.
-  //
-  // Require: GEP GV, 0, i {{, constant indices}}
-  if (GEP->getNumOperands() < 3 ||
-      !isa<ConstantInt>(GEP->getOperand(1)) ||
-      !cast<ConstantInt>(GEP->getOperand(1))->isZero() ||
-      isa<Constant>(GEP->getOperand(2)))
-    return 0;
-
-  // Check that indices after the variable are constants and in-range for the
-  // type they index.  Collect the indices.  This is typically for arrays of
-  // structs.
-  SmallVector<unsigned, 4> LaterIndices;
-  
-  const Type *EltTy = cast<ArrayType>(Init->getType())->getElementType();
-  for (unsigned i = 3, e = GEP->getNumOperands(); i != e; ++i) {
-    ConstantInt *Idx = dyn_cast<ConstantInt>(GEP->getOperand(i));
-    if (Idx == 0) return 0;  // Variable index.
-    
-    uint64_t IdxVal = Idx->getZExtValue();
-    if ((unsigned)IdxVal != IdxVal) return 0; // Too large array index.
-    
-    if (const StructType *STy = dyn_cast<StructType>(EltTy))
-      EltTy = STy->getElementType(IdxVal);
-    else if (const ArrayType *ATy = dyn_cast<ArrayType>(EltTy)) {
-      if (IdxVal >= ATy->getNumElements()) return 0;
-      EltTy = ATy->getElementType();
-    } else {
-      return 0; // Unknown type.
-    }
-    
-    LaterIndices.push_back(IdxVal);
-  }
-  
-  enum { Overdefined = -3, Undefined = -2 };
-
-  // Variables for our state machines.
-  
-  // FirstTrueElement/SecondTrueElement - Used to emit a comparison of the form
-  // "i == 47 | i == 87", where 47 is the first index the condition is true for,
-  // and 87 is the second (and last) index.  FirstTrueElement is -2 when
-  // undefined, otherwise set to the first true element.  SecondTrueElement is
-  // -2 when undefined, -3 when overdefined and >= 0 when that index is true.
-  int FirstTrueElement = Undefined, SecondTrueElement = Undefined;
-
-  // FirstFalseElement/SecondFalseElement - Used to emit a comparison of the
-  // form "i != 47 & i != 87".  Same state transitions as for true elements.
-  int FirstFalseElement = Undefined, SecondFalseElement = Undefined;
-  
-  /// TrueRangeEnd/FalseRangeEnd - In conjunction with First*Element, these
-  /// define a state machine that triggers for ranges of values that the index
-  /// is true or false for.  This triggers on things like "abbbbc"[i] == 'b'.
-  /// This is -2 when undefined, -3 when overdefined, and otherwise the last
-  /// index in the range (inclusive).  We use -2 for undefined here because we
-  /// use relative comparisons and don't want 0-1 to match -1.
-  int TrueRangeEnd = Undefined, FalseRangeEnd = Undefined;
-  
-  // MagicBitvector - This is a magic bitvector where we set a bit if the
-  // comparison is true for element 'i'.  If there are 64 elements or less in
-  // the array, this will fully represent all the comparison results.
-  uint64_t MagicBitvector = 0;
-  
-  
-  // Scan the array and see if one of our patterns matches.
-  Constant *CompareRHS = cast<Constant>(ICI.getOperand(1));
-  for (unsigned i = 0, e = Init->getNumOperands(); i != e; ++i) {
-    Constant *Elt = Init->getOperand(i);
-    
-    // If this is indexing an array of structures, get the structure element.
-    if (!LaterIndices.empty())
-      Elt = ConstantExpr::getExtractValue(Elt, LaterIndices.data(),
-                                          LaterIndices.size());
-    
-    // If the element is masked, handle it.
-    if (AndCst) Elt = ConstantExpr::getAnd(Elt, AndCst);
-    
-    // Find out if the comparison would be true or false for the i'th element.
-    Constant *C = ConstantFoldCompareInstOperands(ICI.getPredicate(), Elt,
-                                                  CompareRHS, TD);
-    // If the result is undef for this element, ignore it.
-    if (isa<UndefValue>(C)) {
-      // Extend range state machines to cover this element in case there is an
-      // undef in the middle of the range.
-      if (TrueRangeEnd == (int)i-1)
-        TrueRangeEnd = i;
-      if (FalseRangeEnd == (int)i-1)
-        FalseRangeEnd = i;
-      continue;
-    }
-    
-    // If we can't compute the result for any of the elements, we have to give
-    // up evaluating the entire conditional.
-    if (!isa<ConstantInt>(C)) return 0;
-    
-    // Otherwise, we know if the comparison is true or false for this element,
-    // update our state machines.
-    bool IsTrueForElt = !cast<ConstantInt>(C)->isZero();
-    
-    // State machine for single/double/range index comparison.
-    if (IsTrueForElt) {
-      // Update the TrueElement state machine.
-      if (FirstTrueElement == Undefined)
-        FirstTrueElement = TrueRangeEnd = i;  // First true element.
-      else {
-        // Update double-compare state machine.
-        if (SecondTrueElement == Undefined)
-          SecondTrueElement = i;
-        else
-          SecondTrueElement = Overdefined;
-        
-        // Update range state machine.
-        if (TrueRangeEnd == (int)i-1)
-          TrueRangeEnd = i;
-        else
-          TrueRangeEnd = Overdefined;
-      }
-    } else {
-      // Update the FalseElement state machine.
-      if (FirstFalseElement == Undefined)
-        FirstFalseElement = FalseRangeEnd = i; // First false element.
-      else {
-        // Update double-compare state machine.
-        if (SecondFalseElement == Undefined)
-          SecondFalseElement = i;
-        else
-          SecondFalseElement = Overdefined;
-        
-        // Update range state machine.
-        if (FalseRangeEnd == (int)i-1)
-          FalseRangeEnd = i;
-        else
-          FalseRangeEnd = Overdefined;
-      }
-    }
-    
-    
-    // If this element is in range, update our magic bitvector.
-    if (i < 64 && IsTrueForElt)
-      MagicBitvector |= 1ULL << i;
-    
-    // If all of our states become overdefined, bail out early.  Since the
-    // predicate is expensive, only check it every 8 elements.  This is only
-    // really useful for really huge arrays.
-    if ((i & 8) == 0 && i >= 64 && SecondTrueElement == Overdefined &&
-        SecondFalseElement == Overdefined && TrueRangeEnd == Overdefined &&
-        FalseRangeEnd == Overdefined)
-      return 0;
-  }
-
-  // Now that we've scanned the entire array, emit our new comparison(s).  We
-  // order the state machines in complexity of the generated code.
-  Value *Idx = GEP->getOperand(2);
-
-  
-  // If the comparison is only true for one or two elements, emit direct
-  // comparisons.
-  if (SecondTrueElement != Overdefined) {
-    // None true -> false.
-    if (FirstTrueElement == Undefined)
-      return ReplaceInstUsesWith(ICI, ConstantInt::getFalse(*Context));
-    
-    Value *FirstTrueIdx = ConstantInt::get(Idx->getType(), FirstTrueElement);
-    
-    // True for one element -> 'i == 47'.
-    if (SecondTrueElement == Undefined)
-      return new ICmpInst(ICmpInst::ICMP_EQ, Idx, FirstTrueIdx);
-    
-    // True for two elements -> 'i == 47 | i == 72'.
-    Value *C1 = Builder->CreateICmpEQ(Idx, FirstTrueIdx);
-    Value *SecondTrueIdx = ConstantInt::get(Idx->getType(), SecondTrueElement);
-    Value *C2 = Builder->CreateICmpEQ(Idx, SecondTrueIdx);
-    return BinaryOperator::CreateOr(C1, C2);
-  }
-
-  // If the comparison is only false for one or two elements, emit direct
-  // comparisons.
-  if (SecondFalseElement != Overdefined) {
-    // None false -> true.
-    if (FirstFalseElement == Undefined)
-      return ReplaceInstUsesWith(ICI, ConstantInt::getTrue(*Context));
-    
-    Value *FirstFalseIdx = ConstantInt::get(Idx->getType(), FirstFalseElement);
-
-    // False for one element -> 'i != 47'.
-    if (SecondFalseElement == Undefined)
-      return new ICmpInst(ICmpInst::ICMP_NE, Idx, FirstFalseIdx);
-     
-    // False for two elements -> 'i != 47 & i != 72'.
-    Value *C1 = Builder->CreateICmpNE(Idx, FirstFalseIdx);
-    Value *SecondFalseIdx = ConstantInt::get(Idx->getType(),SecondFalseElement);
-    Value *C2 = Builder->CreateICmpNE(Idx, SecondFalseIdx);
-    return BinaryOperator::CreateAnd(C1, C2);
-  }
-  
-  // If the comparison can be replaced with a range comparison for the elements
-  // where it is true, emit the range check.
-  if (TrueRangeEnd != Overdefined) {
-    assert(TrueRangeEnd != FirstTrueElement && "Should emit single compare");
-    
-    // Generate (i-FirstTrue) <u (TrueRangeEnd-FirstTrue+1).
-    if (FirstTrueElement) {
-      Value *Offs = ConstantInt::get(Idx->getType(), -FirstTrueElement);
-      Idx = Builder->CreateAdd(Idx, Offs);
-    }
-    
-    Value *End = ConstantInt::get(Idx->getType(),
-                                  TrueRangeEnd-FirstTrueElement+1);
-    return new ICmpInst(ICmpInst::ICMP_ULT, Idx, End);
-  }
-  
-  // False range check.
-  if (FalseRangeEnd != Overdefined) {
-    assert(FalseRangeEnd != FirstFalseElement && "Should emit single compare");
-    // Generate (i-FirstFalse) >u (FalseRangeEnd-FirstFalse).
-    if (FirstFalseElement) {
-      Value *Offs = ConstantInt::get(Idx->getType(), -FirstFalseElement);
-      Idx = Builder->CreateAdd(Idx, Offs);
-    }
-    
-    Value *End = ConstantInt::get(Idx->getType(),
-                                  FalseRangeEnd-FirstFalseElement);
-    return new ICmpInst(ICmpInst::ICMP_UGT, Idx, End);
-  }
-  
-  
-  // If a 32-bit or 64-bit magic bitvector captures the entire comparison state
-  // of this load, replace it with computation that does:
-  //   ((magic_cst >> i) & 1) != 0
-  if (Init->getNumOperands() <= 32 ||
-      (TD && Init->getNumOperands() <= 64 && TD->isLegalInteger(64))) {
-    const Type *Ty;
-    if (Init->getNumOperands() <= 32)
-      Ty = Type::getInt32Ty(Init->getContext());
-    else
-      Ty = Type::getInt64Ty(Init->getContext());
-    Value *V = Builder->CreateIntCast(Idx, Ty, false);
-    V = Builder->CreateLShr(ConstantInt::get(Ty, MagicBitvector), V);
-    V = Builder->CreateAnd(ConstantInt::get(Ty, 1), V);
-    return new ICmpInst(ICmpInst::ICMP_NE, V, ConstantInt::get(Ty, 0));
-  }
-  
-  return 0;
-}
-
-
-Instruction *InstCombiner::visitFCmpInst(FCmpInst &I) {
-  bool Changed = false;
-  
-  /// Orders the operands of the compare so that they are listed from most
-  /// complex to least complex.  This puts constants before unary operators,
-  /// before binary operators.
-  if (getComplexity(I.getOperand(0)) < getComplexity(I.getOperand(1))) {
-    I.swapOperands();
-    Changed = true;
-  }
-
-  Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-  
-  if (Value *V = SimplifyFCmpInst(I.getPredicate(), Op0, Op1, TD))
-    return ReplaceInstUsesWith(I, V);
-
-  // Simplify 'fcmp pred X, X'
-  if (Op0 == Op1) {
-    switch (I.getPredicate()) {
-    default: llvm_unreachable("Unknown predicate!");
-    case FCmpInst::FCMP_UNO:    // True if unordered: isnan(X) | isnan(Y)
-    case FCmpInst::FCMP_ULT:    // True if unordered or less than
-    case FCmpInst::FCMP_UGT:    // True if unordered or greater than
-    case FCmpInst::FCMP_UNE:    // True if unordered or not equal
-      // Canonicalize these to be 'fcmp uno %X, 0.0'.
-      I.setPredicate(FCmpInst::FCMP_UNO);
-      I.setOperand(1, Constant::getNullValue(Op0->getType()));
-      return &I;
-      
-    case FCmpInst::FCMP_ORD:    // True if ordered (no nans)
-    case FCmpInst::FCMP_OEQ:    // True if ordered and equal
-    case FCmpInst::FCMP_OGE:    // True if ordered and greater than or equal
-    case FCmpInst::FCMP_OLE:    // True if ordered and less than or equal
-      // Canonicalize these to be 'fcmp ord %X, 0.0'.
-      I.setPredicate(FCmpInst::FCMP_ORD);
-      I.setOperand(1, Constant::getNullValue(Op0->getType()));
-      return &I;
-    }
-  }
-    
-  // Handle fcmp with constant RHS
-  if (Constant *RHSC = dyn_cast<Constant>(Op1)) {
-    if (Instruction *LHSI = dyn_cast<Instruction>(Op0))
-      switch (LHSI->getOpcode()) {
-      case Instruction::PHI:
-        // Only fold fcmp into the PHI if the phi and fcmp are in the same
-        // block.  If in the same block, we're encouraging jump threading.  If
-        // not, we are just pessimizing the code by making an i1 phi.
-        if (LHSI->getParent() == I.getParent())
-          if (Instruction *NV = FoldOpIntoPhi(I, true))
-            return NV;
-        break;
-      case Instruction::SIToFP:
-      case Instruction::UIToFP:
-        if (Instruction *NV = FoldFCmp_IntToFP_Cst(I, LHSI, RHSC))
-          return NV;
-        break;
-      case Instruction::Select: {
-        // If either operand of the select is a constant, we can fold the
-        // comparison into the select arms, which will cause one to be
-        // constant folded and the select turned into a bitwise or.
-        Value *Op1 = 0, *Op2 = 0;
-        if (LHSI->hasOneUse()) {
-          if (Constant *C = dyn_cast<Constant>(LHSI->getOperand(1))) {
-            // Fold the known value into the constant operand.
-            Op1 = ConstantExpr::getCompare(I.getPredicate(), C, RHSC);
-            // Insert a new FCmp of the other select operand.
-            Op2 = Builder->CreateFCmp(I.getPredicate(),
-                                      LHSI->getOperand(2), RHSC, I.getName());
-          } else if (Constant *C = dyn_cast<Constant>(LHSI->getOperand(2))) {
-            // Fold the known value into the constant operand.
-            Op2 = ConstantExpr::getCompare(I.getPredicate(), C, RHSC);
-            // Insert a new FCmp of the other select operand.
-            Op1 = Builder->CreateFCmp(I.getPredicate(), LHSI->getOperand(1),
-                                      RHSC, I.getName());
-          }
-        }
-
-        if (Op1)
-          return SelectInst::Create(LHSI->getOperand(0), Op1, Op2);
-        break;
-      }
-    case Instruction::Load:
-      if (GetElementPtrInst *GEP =
-          dyn_cast<GetElementPtrInst>(LHSI->getOperand(0))) {
-        if (GlobalVariable *GV = dyn_cast<GlobalVariable>(GEP->getOperand(0)))
-          if (GV->isConstant() && GV->hasDefinitiveInitializer() &&
-              !cast<LoadInst>(LHSI)->isVolatile())
-            if (Instruction *Res = FoldCmpLoadFromIndexedGlobal(GEP, GV, I))
-              return Res;
-      }
-      break;
-    }
-  }
-
-  return Changed ? &I : 0;
-}
-
-Instruction *InstCombiner::visitICmpInst(ICmpInst &I) {
-  bool Changed = false;
-  
-  /// Orders the operands of the compare so that they are listed from most
-  /// complex to least complex.  This puts constants before unary operators,
-  /// before binary operators.
-  if (getComplexity(I.getOperand(0)) < getComplexity(I.getOperand(1))) {
-    I.swapOperands();
-    Changed = true;
-  }
-  
-  Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-  
-  if (Value *V = SimplifyICmpInst(I.getPredicate(), Op0, Op1, TD))
-    return ReplaceInstUsesWith(I, V);
-  
-  const Type *Ty = Op0->getType();
-
-  // icmp's with boolean values can always be turned into bitwise operations
-  if (Ty == Type::getInt1Ty(*Context)) {
-    switch (I.getPredicate()) {
-    default: llvm_unreachable("Invalid icmp instruction!");
-    case ICmpInst::ICMP_EQ: {               // icmp eq i1 A, B -> ~(A^B)
-      Value *Xor = Builder->CreateXor(Op0, Op1, I.getName()+"tmp");
-      return BinaryOperator::CreateNot(Xor);
-    }
-    case ICmpInst::ICMP_NE:                  // icmp eq i1 A, B -> A^B
-      return BinaryOperator::CreateXor(Op0, Op1);
-
-    case ICmpInst::ICMP_UGT:
-      std::swap(Op0, Op1);                   // Change icmp ugt -> icmp ult
-      // FALL THROUGH
-    case ICmpInst::ICMP_ULT:{               // icmp ult i1 A, B -> ~A & B
-      Value *Not = Builder->CreateNot(Op0, I.getName()+"tmp");
-      return BinaryOperator::CreateAnd(Not, Op1);
-    }
-    case ICmpInst::ICMP_SGT:
-      std::swap(Op0, Op1);                   // Change icmp sgt -> icmp slt
-      // FALL THROUGH
-    case ICmpInst::ICMP_SLT: {               // icmp slt i1 A, B -> A & ~B
-      Value *Not = Builder->CreateNot(Op1, I.getName()+"tmp");
-      return BinaryOperator::CreateAnd(Not, Op0);
-    }
-    case ICmpInst::ICMP_UGE:
-      std::swap(Op0, Op1);                   // Change icmp uge -> icmp ule
-      // FALL THROUGH
-    case ICmpInst::ICMP_ULE: {               //  icmp ule i1 A, B -> ~A | B
-      Value *Not = Builder->CreateNot(Op0, I.getName()+"tmp");
-      return BinaryOperator::CreateOr(Not, Op1);
-    }
-    case ICmpInst::ICMP_SGE:
-      std::swap(Op0, Op1);                   // Change icmp sge -> icmp sle
-      // FALL THROUGH
-    case ICmpInst::ICMP_SLE: {               //  icmp sle i1 A, B -> A | ~B
-      Value *Not = Builder->CreateNot(Op1, I.getName()+"tmp");
-      return BinaryOperator::CreateOr(Not, Op0);
-    }
-    }
-  }
-
-  unsigned BitWidth = 0;
-  if (TD)
-    BitWidth = TD->getTypeSizeInBits(Ty->getScalarType());
-  else if (Ty->isIntOrIntVector())
-    BitWidth = Ty->getScalarSizeInBits();
-
-  bool isSignBit = false;
-
-  // See if we are doing a comparison with a constant.
-  if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
-    Value *A = 0, *B = 0;
-    
-    // (icmp ne/eq (sub A B) 0) -> (icmp ne/eq A, B)
-    if (I.isEquality() && CI->isZero() &&
-        match(Op0, m_Sub(m_Value(A), m_Value(B)))) {
-      // (icmp cond A B) if cond is equality
-      return new ICmpInst(I.getPredicate(), A, B);
-    }
-    
-    // If we have an icmp le or icmp ge instruction, turn it into the
-    // appropriate icmp lt or icmp gt instruction.  This allows us to rely on
-    // them being folded in the code below.  The SimplifyICmpInst code has
-    // already handled the edge cases for us, so we just assert on them.
-    switch (I.getPredicate()) {
-    default: break;
-    case ICmpInst::ICMP_ULE:
-      assert(!CI->isMaxValue(false));                 // A <=u MAX -> TRUE
-      return new ICmpInst(ICmpInst::ICMP_ULT, Op0,
-                          AddOne(CI));
-    case ICmpInst::ICMP_SLE:
-      assert(!CI->isMaxValue(true));                  // A <=s MAX -> TRUE
-      return new ICmpInst(ICmpInst::ICMP_SLT, Op0,
-                          AddOne(CI));
-    case ICmpInst::ICMP_UGE:
-      assert(!CI->isMinValue(false));                  // A >=u MIN -> TRUE
-      return new ICmpInst(ICmpInst::ICMP_UGT, Op0,
-                          SubOne(CI));
-    case ICmpInst::ICMP_SGE:
-      assert(!CI->isMinValue(true));                   // A >=s MIN -> TRUE
-      return new ICmpInst(ICmpInst::ICMP_SGT, Op0,
-                          SubOne(CI));
-    }
-    
-    // If this comparison is a normal comparison, it demands all
-    // bits, if it is a sign bit comparison, it only demands the sign bit.
-    bool UnusedBit;
-    isSignBit = isSignBitCheck(I.getPredicate(), CI, UnusedBit);
-  }
-
-  // See if we can fold the comparison based on range information we can get
-  // by checking whether bits are known to be zero or one in the input.
-  if (BitWidth != 0) {
-    APInt Op0KnownZero(BitWidth, 0), Op0KnownOne(BitWidth, 0);
-    APInt Op1KnownZero(BitWidth, 0), Op1KnownOne(BitWidth, 0);
-
-    if (SimplifyDemandedBits(I.getOperandUse(0),
-                             isSignBit ? APInt::getSignBit(BitWidth)
-                                       : APInt::getAllOnesValue(BitWidth),
-                             Op0KnownZero, Op0KnownOne, 0))
-      return &I;
-    if (SimplifyDemandedBits(I.getOperandUse(1),
-                             APInt::getAllOnesValue(BitWidth),
-                             Op1KnownZero, Op1KnownOne, 0))
-      return &I;
-
-    // Given the known and unknown bits, compute a range that the LHS could be
-    // in.  Compute the Min, Max and RHS values based on the known bits. For the
-    // EQ and NE we use unsigned values.
-    APInt Op0Min(BitWidth, 0), Op0Max(BitWidth, 0);
-    APInt Op1Min(BitWidth, 0), Op1Max(BitWidth, 0);
-    if (I.isSigned()) {
-      ComputeSignedMinMaxValuesFromKnownBits(Op0KnownZero, Op0KnownOne,
-                                             Op0Min, Op0Max);
-      ComputeSignedMinMaxValuesFromKnownBits(Op1KnownZero, Op1KnownOne,
-                                             Op1Min, Op1Max);
-    } else {
-      ComputeUnsignedMinMaxValuesFromKnownBits(Op0KnownZero, Op0KnownOne,
-                                               Op0Min, Op0Max);
-      ComputeUnsignedMinMaxValuesFromKnownBits(Op1KnownZero, Op1KnownOne,
-                                               Op1Min, Op1Max);
-    }
-
-    // If Min and Max are known to be the same, then SimplifyDemandedBits
-    // figured out that the LHS is a constant.  Just constant fold this now so
-    // that code below can assume that Min != Max.
-    if (!isa<Constant>(Op0) && Op0Min == Op0Max)
-      return new ICmpInst(I.getPredicate(),
-                          ConstantInt::get(*Context, Op0Min), Op1);
-    if (!isa<Constant>(Op1) && Op1Min == Op1Max)
-      return new ICmpInst(I.getPredicate(), Op0,
-                          ConstantInt::get(*Context, Op1Min));
-
-    // Based on the range information we know about the LHS, see if we can
-    // simplify this comparison.  For example, (x&4) < 8  is always true.
-    switch (I.getPredicate()) {
-    default: llvm_unreachable("Unknown icmp opcode!");
-    case ICmpInst::ICMP_EQ:
-      if (Op0Max.ult(Op1Min) || Op0Min.ugt(Op1Max))
-        return ReplaceInstUsesWith(I, ConstantInt::getFalse(*Context));
-      break;
-    case ICmpInst::ICMP_NE:
-      if (Op0Max.ult(Op1Min) || Op0Min.ugt(Op1Max))
-        return ReplaceInstUsesWith(I, ConstantInt::getTrue(*Context));
-      break;
-    case ICmpInst::ICMP_ULT:
-      if (Op0Max.ult(Op1Min))          // A <u B -> true if max(A) < min(B)
-        return ReplaceInstUsesWith(I, ConstantInt::getTrue(*Context));
-      if (Op0Min.uge(Op1Max))          // A <u B -> false if min(A) >= max(B)
-        return ReplaceInstUsesWith(I, ConstantInt::getFalse(*Context));
-      if (Op1Min == Op0Max)            // A <u B -> A != B if max(A) == min(B)
-        return new ICmpInst(ICmpInst::ICMP_NE, Op0, Op1);
-      if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
-        if (Op1Max == Op0Min+1)        // A <u C -> A == C-1 if min(A)+1 == C
-          return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
-                              SubOne(CI));
-
-        // (x <u 2147483648) -> (x >s -1)  -> true if sign bit clear
-        if (CI->isMinValue(true))
-          return new ICmpInst(ICmpInst::ICMP_SGT, Op0,
-                           Constant::getAllOnesValue(Op0->getType()));
-      }
-      break;
-    case ICmpInst::ICMP_UGT:
-      if (Op0Min.ugt(Op1Max))          // A >u B -> true if min(A) > max(B)
-        return ReplaceInstUsesWith(I, ConstantInt::getTrue(*Context));
-      if (Op0Max.ule(Op1Min))          // A >u B -> false if max(A) <= max(B)
-        return ReplaceInstUsesWith(I, ConstantInt::getFalse(*Context));
-
-      if (Op1Max == Op0Min)            // A >u B -> A != B if min(A) == max(B)
-        return new ICmpInst(ICmpInst::ICMP_NE, Op0, Op1);
-      if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
-        if (Op1Min == Op0Max-1)        // A >u C -> A == C+1 if max(a)-1 == C
-          return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
-                              AddOne(CI));
-
-        // (x >u 2147483647) -> (x <s 0)  -> true if sign bit set
-        if (CI->isMaxValue(true))
-          return new ICmpInst(ICmpInst::ICMP_SLT, Op0,
-                              Constant::getNullValue(Op0->getType()));
-      }
-      break;
-    case ICmpInst::ICMP_SLT:
-      if (Op0Max.slt(Op1Min))          // A <s B -> true if max(A) < min(C)
-        return ReplaceInstUsesWith(I, ConstantInt::getTrue(*Context));
-      if (Op0Min.sge(Op1Max))          // A <s B -> false if min(A) >= max(C)
-        return ReplaceInstUsesWith(I, ConstantInt::getFalse(*Context));
-      if (Op1Min == Op0Max)            // A <s B -> A != B if max(A) == min(B)
-        return new ICmpInst(ICmpInst::ICMP_NE, Op0, Op1);
-      if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
-        if (Op1Max == Op0Min+1)        // A <s C -> A == C-1 if min(A)+1 == C
-          return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
-                              SubOne(CI));
-      }
-      break;
-    case ICmpInst::ICMP_SGT:
-      if (Op0Min.sgt(Op1Max))          // A >s B -> true if min(A) > max(B)
-        return ReplaceInstUsesWith(I, ConstantInt::getTrue(*Context));
-      if (Op0Max.sle(Op1Min))          // A >s B -> false if max(A) <= min(B)
-        return ReplaceInstUsesWith(I, ConstantInt::getFalse(*Context));
-
-      if (Op1Max == Op0Min)            // A >s B -> A != B if min(A) == max(B)
-        return new ICmpInst(ICmpInst::ICMP_NE, Op0, Op1);
-      if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
-        if (Op1Min == Op0Max-1)        // A >s C -> A == C+1 if max(A)-1 == C
-          return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
-                              AddOne(CI));
-      }
-      break;
-    case ICmpInst::ICMP_SGE:
-      assert(!isa<ConstantInt>(Op1) && "ICMP_SGE with ConstantInt not folded!");
-      if (Op0Min.sge(Op1Max))          // A >=s B -> true if min(A) >= max(B)
-        return ReplaceInstUsesWith(I, ConstantInt::getTrue(*Context));
-      if (Op0Max.slt(Op1Min))          // A >=s B -> false if max(A) < min(B)
-        return ReplaceInstUsesWith(I, ConstantInt::getFalse(*Context));
-      break;
-    case ICmpInst::ICMP_SLE:
-      assert(!isa<ConstantInt>(Op1) && "ICMP_SLE with ConstantInt not folded!");
-      if (Op0Max.sle(Op1Min))          // A <=s B -> true if max(A) <= min(B)
-        return ReplaceInstUsesWith(I, ConstantInt::getTrue(*Context));
-      if (Op0Min.sgt(Op1Max))          // A <=s B -> false if min(A) > max(B)
-        return ReplaceInstUsesWith(I, ConstantInt::getFalse(*Context));
-      break;
-    case ICmpInst::ICMP_UGE:
-      assert(!isa<ConstantInt>(Op1) && "ICMP_UGE with ConstantInt not folded!");
-      if (Op0Min.uge(Op1Max))          // A >=u B -> true if min(A) >= max(B)
-        return ReplaceInstUsesWith(I, ConstantInt::getTrue(*Context));
-      if (Op0Max.ult(Op1Min))          // A >=u B -> false if max(A) < min(B)
-        return ReplaceInstUsesWith(I, ConstantInt::getFalse(*Context));
-      break;
-    case ICmpInst::ICMP_ULE:
-      assert(!isa<ConstantInt>(Op1) && "ICMP_ULE with ConstantInt not folded!");
-      if (Op0Max.ule(Op1Min))          // A <=u B -> true if max(A) <= min(B)
-        return ReplaceInstUsesWith(I, ConstantInt::getTrue(*Context));
-      if (Op0Min.ugt(Op1Max))          // A <=u B -> false if min(A) > max(B)
-        return ReplaceInstUsesWith(I, ConstantInt::getFalse(*Context));
-      break;
-    }
-
-    // Turn a signed comparison into an unsigned one if both operands
-    // are known to have the same sign.
-    if (I.isSigned() &&
-        ((Op0KnownZero.isNegative() && Op1KnownZero.isNegative()) ||
-         (Op0KnownOne.isNegative() && Op1KnownOne.isNegative())))
-      return new ICmpInst(I.getUnsignedPredicate(), Op0, Op1);
-  }
-
-  // Test if the ICmpInst instruction is used exclusively by a select as
-  // part of a minimum or maximum operation. If so, refrain from doing
-  // any other folding. This helps out other analyses which understand
-  // non-obfuscated minimum and maximum idioms, such as ScalarEvolution
-  // and CodeGen. And in this case, at least one of the comparison
-  // operands has at least one user besides the compare (the select),
-  // which would often largely negate the benefit of folding anyway.
-  if (I.hasOneUse())
-    if (SelectInst *SI = dyn_cast<SelectInst>(*I.use_begin()))
-      if ((SI->getOperand(1) == Op0 && SI->getOperand(2) == Op1) ||
-          (SI->getOperand(2) == Op0 && SI->getOperand(1) == Op1))
-        return 0;
-
-  // See if we are doing a comparison between a constant and an instruction that
-  // can be folded into the comparison.
-  if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
-    // Since the RHS is a ConstantInt (CI), if the left hand side is an 
-    // instruction, see if that instruction also has constants so that the 
-    // instruction can be folded into the icmp 
-    if (Instruction *LHSI = dyn_cast<Instruction>(Op0))
-      if (Instruction *Res = visitICmpInstWithInstAndIntCst(I, LHSI, CI))
-        return Res;
-  }
-
-  // Handle icmp with constant (but not simple integer constant) RHS
-  if (Constant *RHSC = dyn_cast<Constant>(Op1)) {
-    if (Instruction *LHSI = dyn_cast<Instruction>(Op0))
-      switch (LHSI->getOpcode()) {
-      case Instruction::GetElementPtr:
-          // icmp pred GEP (P, int 0, int 0, int 0), null -> icmp pred P, null
-        if (RHSC->isNullValue() &&
-            cast<GetElementPtrInst>(LHSI)->hasAllZeroIndices())
-          return new ICmpInst(I.getPredicate(), LHSI->getOperand(0),
-                  Constant::getNullValue(LHSI->getOperand(0)->getType()));
-        break;
-      case Instruction::PHI:
-        // Only fold icmp into the PHI if the phi and icmp are in the same
-        // block.  If in the same block, we're encouraging jump threading.  If
-        // not, we are just pessimizing the code by making an i1 phi.
-        if (LHSI->getParent() == I.getParent())
-          if (Instruction *NV = FoldOpIntoPhi(I, true))
-            return NV;
-        break;
-      case Instruction::Select: {
-        // If either operand of the select is a constant, we can fold the
-        // comparison into the select arms, which will cause one to be
-        // constant folded and the select turned into a bitwise or.
-        Value *Op1 = 0, *Op2 = 0;
-        if (Constant *C = dyn_cast<Constant>(LHSI->getOperand(1)))
-          Op1 = ConstantExpr::getICmp(I.getPredicate(), C, RHSC);
-        if (Constant *C = dyn_cast<Constant>(LHSI->getOperand(2)))
-          Op2 = ConstantExpr::getICmp(I.getPredicate(), C, RHSC);
-
-        // We only want to perform this transformation if it will not lead to
-        // additional code. This is true if either both sides of the select
-        // fold to a constant (in which case the icmp is replaced with a select
-        // which will usually simplify) or this is the only user of the
-        // select (in which case we are trading a select+icmp for a simpler
-        // select+icmp).
-        if ((Op1 && Op2) || (LHSI->hasOneUse() && (Op1 || Op2))) {
-          if (!Op1)
-            Op1 = Builder->CreateICmp(I.getPredicate(), LHSI->getOperand(1),
-                                      RHSC, I.getName());
-          if (!Op2)
-            Op2 = Builder->CreateICmp(I.getPredicate(), LHSI->getOperand(2),
-                                      RHSC, I.getName());
-          return SelectInst::Create(LHSI->getOperand(0), Op1, Op2);
-        }
-        break;
-      }
-      case Instruction::Call:
-        // If we have (malloc != null), and if the malloc has a single use, we
-        // can assume it is successful and remove the malloc.
-        if (isMalloc(LHSI) && LHSI->hasOneUse() &&
-            isa<ConstantPointerNull>(RHSC)) {
-          // Need to explicitly erase malloc call here, instead of adding it to
-          // Worklist, because it won't get DCE'd from the Worklist since
-          // isInstructionTriviallyDead() returns false for function calls.
-          // It is OK to replace LHSI/MallocCall with Undef because the 
-          // instruction that uses it will be erased via Worklist.
-          if (extractMallocCall(LHSI)) {
-            LHSI->replaceAllUsesWith(UndefValue::get(LHSI->getType()));
-            EraseInstFromFunction(*LHSI);
-            return ReplaceInstUsesWith(I,
-                                     ConstantInt::get(Type::getInt1Ty(*Context),
-                                                      !I.isTrueWhenEqual()));
-          }
-          if (CallInst* MallocCall = extractMallocCallFromBitCast(LHSI))
-            if (MallocCall->hasOneUse()) {
-              MallocCall->replaceAllUsesWith(
-                                        UndefValue::get(MallocCall->getType()));
-              EraseInstFromFunction(*MallocCall);
-              Worklist.Add(LHSI); // The malloc's bitcast use.
-              return ReplaceInstUsesWith(I,
-                                     ConstantInt::get(Type::getInt1Ty(*Context),
-                                                      !I.isTrueWhenEqual()));
-            }
-        }
-        break;
-      case Instruction::IntToPtr:
-        // icmp pred inttoptr(X), null -> icmp pred X, 0
-        if (RHSC->isNullValue() && TD &&
-            TD->getIntPtrType(RHSC->getContext()) == 
-               LHSI->getOperand(0)->getType())
-          return new ICmpInst(I.getPredicate(), LHSI->getOperand(0),
-                        Constant::getNullValue(LHSI->getOperand(0)->getType()));
-        break;
-
-      case Instruction::Load:
-        // Try to optimize things like "A[i] > 4" to index computations.
-        if (GetElementPtrInst *GEP =
-              dyn_cast<GetElementPtrInst>(LHSI->getOperand(0))) {
-          if (GlobalVariable *GV = dyn_cast<GlobalVariable>(GEP->getOperand(0)))
-            if (GV->isConstant() && GV->hasDefinitiveInitializer() &&
-                !cast<LoadInst>(LHSI)->isVolatile())
-              if (Instruction *Res = FoldCmpLoadFromIndexedGlobal(GEP, GV, I))
-                return Res;
-        }
-        break;
-      }
-  }
-
-  // If we can optimize a 'icmp GEP, P' or 'icmp P, GEP', do so now.
-  if (GEPOperator *GEP = dyn_cast<GEPOperator>(Op0))
-    if (Instruction *NI = FoldGEPICmp(GEP, Op1, I.getPredicate(), I))
-      return NI;
-  if (GEPOperator *GEP = dyn_cast<GEPOperator>(Op1))
-    if (Instruction *NI = FoldGEPICmp(GEP, Op0,
-                           ICmpInst::getSwappedPredicate(I.getPredicate()), I))
-      return NI;
-
-  // Test to see if the operands of the icmp are casted versions of other
-  // values.  If the ptr->ptr cast can be stripped off both arguments, we do so
-  // now.
-  if (BitCastInst *CI = dyn_cast<BitCastInst>(Op0)) {
-    if (isa<PointerType>(Op0->getType()) && 
-        (isa<Constant>(Op1) || isa<BitCastInst>(Op1))) { 
-      // We keep moving the cast from the left operand over to the right
-      // operand, where it can often be eliminated completely.
-      Op0 = CI->getOperand(0);
-
-      // If operand #1 is a bitcast instruction, it must also be a ptr->ptr cast
-      // so eliminate it as well.
-      if (BitCastInst *CI2 = dyn_cast<BitCastInst>(Op1))
-        Op1 = CI2->getOperand(0);
-
-      // If Op1 is a constant, we can fold the cast into the constant.
-      if (Op0->getType() != Op1->getType()) {
-        if (Constant *Op1C = dyn_cast<Constant>(Op1)) {
-          Op1 = ConstantExpr::getBitCast(Op1C, Op0->getType());
-        } else {
-          // Otherwise, cast the RHS right before the icmp
-          Op1 = Builder->CreateBitCast(Op1, Op0->getType());
-        }
-      }
-      return new ICmpInst(I.getPredicate(), Op0, Op1);
-    }
-  }
-  
-  if (isa<CastInst>(Op0)) {
-    // Handle the special case of: icmp (cast bool to X), <cst>
-    // This comes up when you have code like
-    //   int X = A < B;
-    //   if (X) ...
-    // For generality, we handle any zero-extension of any operand comparison
-    // with a constant or another cast from the same type.
-    if (isa<Constant>(Op1) || isa<CastInst>(Op1))
-      if (Instruction *R = visitICmpInstWithCastAndCast(I))
-        return R;
-  }
-  
-  // See if it's the same type of instruction on the left and right.
-  if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) {
-    if (BinaryOperator *Op1I = dyn_cast<BinaryOperator>(Op1)) {
-      if (Op0I->getOpcode() == Op1I->getOpcode() && Op0I->hasOneUse() &&
-          Op1I->hasOneUse() && Op0I->getOperand(1) == Op1I->getOperand(1)) {
-        switch (Op0I->getOpcode()) {
-        default: break;
-        case Instruction::Add:
-        case Instruction::Sub:
-        case Instruction::Xor:
-          if (I.isEquality())    // a+x icmp eq/ne b+x --> a icmp b
-            return new ICmpInst(I.getPredicate(), Op0I->getOperand(0),
-                                Op1I->getOperand(0));
-          // icmp u/s (a ^ signbit), (b ^ signbit) --> icmp s/u a, b
-          if (ConstantInt *CI = dyn_cast<ConstantInt>(Op0I->getOperand(1))) {
-            if (CI->getValue().isSignBit()) {
-              ICmpInst::Predicate Pred = I.isSigned()
-                                             ? I.getUnsignedPredicate()
-                                             : I.getSignedPredicate();
-              return new ICmpInst(Pred, Op0I->getOperand(0),
-                                  Op1I->getOperand(0));
-            }
-            
-            if (CI->getValue().isMaxSignedValue()) {
-              ICmpInst::Predicate Pred = I.isSigned()
-                                             ? I.getUnsignedPredicate()
-                                             : I.getSignedPredicate();
-              Pred = I.getSwappedPredicate(Pred);
-              return new ICmpInst(Pred, Op0I->getOperand(0),
-                                  Op1I->getOperand(0));
-            }
-          }
-          break;
-        case Instruction::Mul:
-          if (!I.isEquality())
-            break;
-
-          if (ConstantInt *CI = dyn_cast<ConstantInt>(Op0I->getOperand(1))) {
-            // a * Cst icmp eq/ne b * Cst --> a & Mask icmp b & Mask
-            // Mask = -1 >> count-trailing-zeros(Cst).
-            if (!CI->isZero() && !CI->isOne()) {
-              const APInt &AP = CI->getValue();
-              ConstantInt *Mask = ConstantInt::get(*Context, 
-                                      APInt::getLowBitsSet(AP.getBitWidth(),
-                                                           AP.getBitWidth() -
-                                                      AP.countTrailingZeros()));
-              Value *And1 = Builder->CreateAnd(Op0I->getOperand(0), Mask);
-              Value *And2 = Builder->CreateAnd(Op1I->getOperand(0), Mask);
-              return new ICmpInst(I.getPredicate(), And1, And2);
-            }
-          }
-          break;
-        }
-      }
-    }
-  }
-  
-  // ~x < ~y --> y < x
-  { Value *A, *B;
-    if (match(Op0, m_Not(m_Value(A))) &&
-        match(Op1, m_Not(m_Value(B))))
-      return new ICmpInst(I.getPredicate(), B, A);
-  }
-  
-  if (I.isEquality()) {
-    Value *A, *B, *C, *D;
-    
-    // -x == -y --> x == y
-    if (match(Op0, m_Neg(m_Value(A))) &&
-        match(Op1, m_Neg(m_Value(B))))
-      return new ICmpInst(I.getPredicate(), A, B);
-    
-    if (match(Op0, m_Xor(m_Value(A), m_Value(B)))) {
-      if (A == Op1 || B == Op1) {    // (A^B) == A  ->  B == 0
-        Value *OtherVal = A == Op1 ? B : A;
-        return new ICmpInst(I.getPredicate(), OtherVal,
-                            Constant::getNullValue(A->getType()));
-      }
-
-      if (match(Op1, m_Xor(m_Value(C), m_Value(D)))) {
-        // A^c1 == C^c2 --> A == C^(c1^c2)
-        ConstantInt *C1, *C2;
-        if (match(B, m_ConstantInt(C1)) &&
-            match(D, m_ConstantInt(C2)) && Op1->hasOneUse()) {
-          Constant *NC = 
-                   ConstantInt::get(*Context, C1->getValue() ^ C2->getValue());
-          Value *Xor = Builder->CreateXor(C, NC, "tmp");
-          return new ICmpInst(I.getPredicate(), A, Xor);
-        }
-        
-        // A^B == A^D -> B == D
-        if (A == C) return new ICmpInst(I.getPredicate(), B, D);
-        if (A == D) return new ICmpInst(I.getPredicate(), B, C);
-        if (B == C) return new ICmpInst(I.getPredicate(), A, D);
-        if (B == D) return new ICmpInst(I.getPredicate(), A, C);
-      }
-    }
-    
-    if (match(Op1, m_Xor(m_Value(A), m_Value(B))) &&
-        (A == Op0 || B == Op0)) {
-      // A == (A^B)  ->  B == 0
-      Value *OtherVal = A == Op0 ? B : A;
-      return new ICmpInst(I.getPredicate(), OtherVal,
-                          Constant::getNullValue(A->getType()));
-    }
-
-    // (A-B) == A  ->  B == 0
-    if (match(Op0, m_Sub(m_Specific(Op1), m_Value(B))))
-      return new ICmpInst(I.getPredicate(), B, 
-                          Constant::getNullValue(B->getType()));
-
-    // A == (A-B)  ->  B == 0
-    if (match(Op1, m_Sub(m_Specific(Op0), m_Value(B))))
-      return new ICmpInst(I.getPredicate(), B,
-                          Constant::getNullValue(B->getType()));
-    
-    // (X&Z) == (Y&Z) -> (X^Y) & Z == 0
-    if (Op0->hasOneUse() && Op1->hasOneUse() &&
-        match(Op0, m_And(m_Value(A), m_Value(B))) && 
-        match(Op1, m_And(m_Value(C), m_Value(D)))) {
-      Value *X = 0, *Y = 0, *Z = 0;
-      
-      if (A == C) {
-        X = B; Y = D; Z = A;
-      } else if (A == D) {
-        X = B; Y = C; Z = A;
-      } else if (B == C) {
-        X = A; Y = D; Z = B;
-      } else if (B == D) {
-        X = A; Y = C; Z = B;
-      }
-      
-      if (X) {   // Build (X^Y) & Z
-        Op1 = Builder->CreateXor(X, Y, "tmp");
-        Op1 = Builder->CreateAnd(Op1, Z, "tmp");
-        I.setOperand(0, Op1);
-        I.setOperand(1, Constant::getNullValue(Op1->getType()));
-        return &I;
-      }
-    }
-  }
-  
-  {
-    Value *X; ConstantInt *Cst;
-    // icmp X+Cst, X
-    if (match(Op0, m_Add(m_Value(X), m_ConstantInt(Cst))) && Op1 == X)
-      return FoldICmpAddOpCst(I, X, Cst, I.getPredicate(), Op0);
-
-    // icmp X, X+Cst
-    if (match(Op1, m_Add(m_Value(X), m_ConstantInt(Cst))) && Op0 == X)
-      return FoldICmpAddOpCst(I, X, Cst, I.getSwappedPredicate(), Op1);
-  }
-  return Changed ? &I : 0;
-}
-
-/// FoldICmpAddOpCst - Fold "icmp pred (X+CI), X".
-Instruction *InstCombiner::FoldICmpAddOpCst(ICmpInst &ICI,
-                                            Value *X, ConstantInt *CI,
-                                            ICmpInst::Predicate Pred,
-                                            Value *TheAdd) {
-  // If we have X+0, exit early (simplifying logic below) and let it get folded
-  // elsewhere.   icmp X+0, X  -> icmp X, X
-  if (CI->isZero()) {
-    bool isTrue = ICmpInst::isTrueWhenEqual(Pred);
-    return ReplaceInstUsesWith(ICI, ConstantInt::get(ICI.getType(), isTrue));
-  }
-  
-  // (X+4) == X -> false.
-  if (Pred == ICmpInst::ICMP_EQ)
-    return ReplaceInstUsesWith(ICI, ConstantInt::getFalse(X->getContext()));
-
-  // (X+4) != X -> true.
-  if (Pred == ICmpInst::ICMP_NE)
-    return ReplaceInstUsesWith(ICI, ConstantInt::getTrue(X->getContext()));
-
-  // If this is an instruction (as opposed to constantexpr) get NUW/NSW info.
-  bool isNUW = false, isNSW = false;
-  if (BinaryOperator *Add = dyn_cast<BinaryOperator>(TheAdd)) {
-    isNUW = Add->hasNoUnsignedWrap();
-    isNSW = Add->hasNoSignedWrap();
-  }      
-  
-  // From this point on, we know that (X+C <= X) --> (X+C < X) because C != 0,
-  // so the values can never be equal.  Similiarly for all other "or equals"
-  // operators.
-  
-  // (X+1) <u X        --> X >u (MAXUINT-1)        --> X != 255
-  // (X+2) <u X        --> X >u (MAXUINT-2)        --> X > 253
-  // (X+MAXUINT) <u X  --> X >u (MAXUINT-MAXUINT)  --> X != 0
-  if (Pred == ICmpInst::ICMP_ULT || Pred == ICmpInst::ICMP_ULE) {
-    // If this is an NUW add, then this is always false.
-    if (isNUW)
-      return ReplaceInstUsesWith(ICI, ConstantInt::getFalse(X->getContext())); 
-    
-    Value *R = ConstantExpr::getSub(ConstantInt::get(CI->getType(), -1ULL), CI);
-    return new ICmpInst(ICmpInst::ICMP_UGT, X, R);
-  }
-  
-  // (X+1) >u X        --> X <u (0-1)        --> X != 255
-  // (X+2) >u X        --> X <u (0-2)        --> X <u 254
-  // (X+MAXUINT) >u X  --> X <u (0-MAXUINT)  --> X <u 1  --> X == 0
-  if (Pred == ICmpInst::ICMP_UGT || Pred == ICmpInst::ICMP_UGE) {
-    // If this is an NUW add, then this is always true.
-    if (isNUW)
-      return ReplaceInstUsesWith(ICI, ConstantInt::getTrue(X->getContext())); 
-    return new ICmpInst(ICmpInst::ICMP_ULT, X, ConstantExpr::getNeg(CI));
-  }
-  
-  unsigned BitWidth = CI->getType()->getPrimitiveSizeInBits();
-  ConstantInt *SMax = ConstantInt::get(X->getContext(),
-                                       APInt::getSignedMaxValue(BitWidth));
-
-  // (X+ 1) <s X       --> X >s (MAXSINT-1)          --> X == 127
-  // (X+ 2) <s X       --> X >s (MAXSINT-2)          --> X >s 125
-  // (X+MAXSINT) <s X  --> X >s (MAXSINT-MAXSINT)    --> X >s 0
-  // (X+MINSINT) <s X  --> X >s (MAXSINT-MINSINT)    --> X >s -1
-  // (X+ -2) <s X      --> X >s (MAXSINT- -2)        --> X >s 126
-  // (X+ -1) <s X      --> X >s (MAXSINT- -1)        --> X != 127
-  if (Pred == ICmpInst::ICMP_SLT || Pred == ICmpInst::ICMP_SLE) {
-    // If this is an NSW add, then we have two cases: if the constant is
-    // positive, then this is always false, if negative, this is always true.
-    if (isNSW) {
-      bool isTrue = CI->getValue().isNegative();
-      return ReplaceInstUsesWith(ICI, ConstantInt::get(ICI.getType(), isTrue));
-    }
-    
-    return new ICmpInst(ICmpInst::ICMP_SGT, X, ConstantExpr::getSub(SMax, CI));
-  }
-  
-  // (X+ 1) >s X       --> X <s (MAXSINT-(1-1))       --> X != 127
-  // (X+ 2) >s X       --> X <s (MAXSINT-(2-1))       --> X <s 126
-  // (X+MAXSINT) >s X  --> X <s (MAXSINT-(MAXSINT-1)) --> X <s 1
-  // (X+MINSINT) >s X  --> X <s (MAXSINT-(MINSINT-1)) --> X <s -2
-  // (X+ -2) >s X      --> X <s (MAXSINT-(-2-1))      --> X <s -126
-  // (X+ -1) >s X      --> X <s (MAXSINT-(-1-1))      --> X == -128
-  
-  // If this is an NSW add, then we have two cases: if the constant is
-  // positive, then this is always true, if negative, this is always false.
-  if (isNSW) {
-    bool isTrue = !CI->getValue().isNegative();
-    return ReplaceInstUsesWith(ICI, ConstantInt::get(ICI.getType(), isTrue));
-  }
-  
-  assert(Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SGE);
-  Constant *C = ConstantInt::get(X->getContext(), CI->getValue()-1);
-  return new ICmpInst(ICmpInst::ICMP_SLT, X, ConstantExpr::getSub(SMax, C));
-}
-
-/// FoldICmpDivCst - Fold "icmp pred, ([su]div X, DivRHS), CmpRHS" where DivRHS
-/// and CmpRHS are both known to be integer constants.
-Instruction *InstCombiner::FoldICmpDivCst(ICmpInst &ICI, BinaryOperator *DivI,
-                                          ConstantInt *DivRHS) {
-  ConstantInt *CmpRHS = cast<ConstantInt>(ICI.getOperand(1));
-  const APInt &CmpRHSV = CmpRHS->getValue();
-  
-  // FIXME: If the operand types don't match the type of the divide 
-  // then don't attempt this transform. The code below doesn't have the
-  // logic to deal with a signed divide and an unsigned compare (and
-  // vice versa). This is because (x /s C1) <s C2  produces different 
-  // results than (x /s C1) <u C2 or (x /u C1) <s C2 or even
-  // (x /u C1) <u C2.  Simply casting the operands and result won't 
-  // work. :(  The if statement below tests that condition and bails 
-  // if it finds it. 
-  bool DivIsSigned = DivI->getOpcode() == Instruction::SDiv;
-  if (!ICI.isEquality() && DivIsSigned != ICI.isSigned())
-    return 0;
-  if (DivRHS->isZero())
-    return 0; // The ProdOV computation fails on divide by zero.
-  if (DivIsSigned && DivRHS->isAllOnesValue())
-    return 0; // The overflow computation also screws up here
-  if (DivRHS->isOne())
-    return 0; // Not worth bothering, and eliminates some funny cases
-              // with INT_MIN.
-
-  // Compute Prod = CI * DivRHS. We are essentially solving an equation
-  // of form X/C1=C2. We solve for X by multiplying C1 (DivRHS) and 
-  // C2 (CI). By solving for X we can turn this into a range check 
-  // instead of computing a divide. 
-  Constant *Prod = ConstantExpr::getMul(CmpRHS, DivRHS);
-
-  // Determine if the product overflows by seeing if the product is
-  // not equal to the divide. Make sure we do the same kind of divide
-  // as in the LHS instruction that we're folding. 
-  bool ProdOV = (DivIsSigned ? ConstantExpr::getSDiv(Prod, DivRHS) :
-                 ConstantExpr::getUDiv(Prod, DivRHS)) != CmpRHS;
-
-  // Get the ICmp opcode
-  ICmpInst::Predicate Pred = ICI.getPredicate();
-
-  // Figure out the interval that is being checked.  For example, a comparison
-  // like "X /u 5 == 0" is really checking that X is in the interval [0, 5). 
-  // Compute this interval based on the constants involved and the signedness of
-  // the compare/divide.  This computes a half-open interval, keeping track of
-  // whether either value in the interval overflows.  After analysis each
-  // overflow variable is set to 0 if it's corresponding bound variable is valid
-  // -1 if overflowed off the bottom end, or +1 if overflowed off the top end.
-  int LoOverflow = 0, HiOverflow = 0;
-  Constant *LoBound = 0, *HiBound = 0;
-  
-  if (!DivIsSigned) {  // udiv
-    // e.g. X/5 op 3  --> [15, 20)
-    LoBound = Prod;
-    HiOverflow = LoOverflow = ProdOV;
-    if (!HiOverflow)
-      HiOverflow = AddWithOverflow(HiBound, LoBound, DivRHS, Context, false);
-  } else if (DivRHS->getValue().isStrictlyPositive()) { // Divisor is > 0.
-    if (CmpRHSV == 0) {       // (X / pos) op 0
-      // Can't overflow.  e.g.  X/2 op 0 --> [-1, 2)
-      LoBound = cast<ConstantInt>(ConstantExpr::getNeg(SubOne(DivRHS)));
-      HiBound = DivRHS;
-    } else if (CmpRHSV.isStrictlyPositive()) {   // (X / pos) op pos
-      LoBound = Prod;     // e.g.   X/5 op 3 --> [15, 20)
-      HiOverflow = LoOverflow = ProdOV;
-      if (!HiOverflow)
-        HiOverflow = AddWithOverflow(HiBound, Prod, DivRHS, Context, true);
-    } else {                       // (X / pos) op neg
-      // e.g. X/5 op -3  --> [-15-4, -15+1) --> [-19, -14)
-      HiBound = AddOne(Prod);
-      LoOverflow = HiOverflow = ProdOV ? -1 : 0;
-      if (!LoOverflow) {
-        ConstantInt* DivNeg =
-                         cast<ConstantInt>(ConstantExpr::getNeg(DivRHS));
-        LoOverflow = AddWithOverflow(LoBound, HiBound, DivNeg, Context,
-                                     true) ? -1 : 0;
-       }
-    }
-  } else if (DivRHS->getValue().isNegative()) { // Divisor is < 0.
-    if (CmpRHSV == 0) {       // (X / neg) op 0
-      // e.g. X/-5 op 0  --> [-4, 5)
-      LoBound = AddOne(DivRHS);
-      HiBound = cast<ConstantInt>(ConstantExpr::getNeg(DivRHS));
-      if (HiBound == DivRHS) {     // -INTMIN = INTMIN
-        HiOverflow = 1;            // [INTMIN+1, overflow)
-        HiBound = 0;               // e.g. X/INTMIN = 0 --> X > INTMIN
-      }
-    } else if (CmpRHSV.isStrictlyPositive()) {   // (X / neg) op pos
-      // e.g. X/-5 op 3  --> [-19, -14)
-      HiBound = AddOne(Prod);
-      HiOverflow = LoOverflow = ProdOV ? -1 : 0;
-      if (!LoOverflow)
-        LoOverflow = AddWithOverflow(LoBound, HiBound,
-                                     DivRHS, Context, true) ? -1 : 0;
-    } else {                       // (X / neg) op neg
-      LoBound = Prod;       // e.g. X/-5 op -3  --> [15, 20)
-      LoOverflow = HiOverflow = ProdOV;
-      if (!HiOverflow)
-        HiOverflow = SubWithOverflow(HiBound, Prod, DivRHS, Context, true);
-    }
-    
-    // Dividing by a negative swaps the condition.  LT <-> GT
-    Pred = ICmpInst::getSwappedPredicate(Pred);
-  }
-
-  Value *X = DivI->getOperand(0);
-  switch (Pred) {
-  default: llvm_unreachable("Unhandled icmp opcode!");
-  case ICmpInst::ICMP_EQ:
-    if (LoOverflow && HiOverflow)
-      return ReplaceInstUsesWith(ICI, ConstantInt::getFalse(*Context));
-    else if (HiOverflow)
-      return new ICmpInst(DivIsSigned ? ICmpInst::ICMP_SGE :
-                          ICmpInst::ICMP_UGE, X, LoBound);
-    else if (LoOverflow)
-      return new ICmpInst(DivIsSigned ? ICmpInst::ICMP_SLT :
-                          ICmpInst::ICMP_ULT, X, HiBound);
-    else
-      return InsertRangeTest(X, LoBound, HiBound, DivIsSigned, true, ICI);
-  case ICmpInst::ICMP_NE:
-    if (LoOverflow && HiOverflow)
-      return ReplaceInstUsesWith(ICI, ConstantInt::getTrue(*Context));
-    else if (HiOverflow)
-      return new ICmpInst(DivIsSigned ? ICmpInst::ICMP_SLT :
-                          ICmpInst::ICMP_ULT, X, LoBound);
-    else if (LoOverflow)
-      return new ICmpInst(DivIsSigned ? ICmpInst::ICMP_SGE :
-                          ICmpInst::ICMP_UGE, X, HiBound);
-    else
-      return InsertRangeTest(X, LoBound, HiBound, DivIsSigned, false, ICI);
-  case ICmpInst::ICMP_ULT:
-  case ICmpInst::ICMP_SLT:
-    if (LoOverflow == +1)   // Low bound is greater than input range.
-      return ReplaceInstUsesWith(ICI, ConstantInt::getTrue(*Context));
-    if (LoOverflow == -1)   // Low bound is less than input range.
-      return ReplaceInstUsesWith(ICI, ConstantInt::getFalse(*Context));
-    return new ICmpInst(Pred, X, LoBound);
-  case ICmpInst::ICMP_UGT:
-  case ICmpInst::ICMP_SGT:
-    if (HiOverflow == +1)       // High bound greater than input range.
-      return ReplaceInstUsesWith(ICI, ConstantInt::getFalse(*Context));
-    else if (HiOverflow == -1)  // High bound less than input range.
-      return ReplaceInstUsesWith(ICI, ConstantInt::getTrue(*Context));
-    if (Pred == ICmpInst::ICMP_UGT)
-      return new ICmpInst(ICmpInst::ICMP_UGE, X, HiBound);
-    else
-      return new ICmpInst(ICmpInst::ICMP_SGE, X, HiBound);
-  }
-}
-
-
-/// visitICmpInstWithInstAndIntCst - Handle "icmp (instr, intcst)".
-///
-Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI,
-                                                          Instruction *LHSI,
-                                                          ConstantInt *RHS) {
-  const APInt &RHSV = RHS->getValue();
-  
-  switch (LHSI->getOpcode()) {
-  case Instruction::Trunc:
-    if (ICI.isEquality() && LHSI->hasOneUse()) {
-      // Simplify icmp eq (trunc x to i8), 42 -> icmp eq x, 42|highbits if all
-      // of the high bits truncated out of x are known.
-      unsigned DstBits = LHSI->getType()->getPrimitiveSizeInBits(),
-             SrcBits = LHSI->getOperand(0)->getType()->getPrimitiveSizeInBits();
-      APInt Mask(APInt::getHighBitsSet(SrcBits, SrcBits-DstBits));
-      APInt KnownZero(SrcBits, 0), KnownOne(SrcBits, 0);
-      ComputeMaskedBits(LHSI->getOperand(0), Mask, KnownZero, KnownOne);
-      
-      // If all the high bits are known, we can do this xform.
-      if ((KnownZero|KnownOne).countLeadingOnes() >= SrcBits-DstBits) {
-        // Pull in the high bits from known-ones set.
-        APInt NewRHS(RHS->getValue());
-        NewRHS.zext(SrcBits);
-        NewRHS |= KnownOne;
-        return new ICmpInst(ICI.getPredicate(), LHSI->getOperand(0),
-                            ConstantInt::get(*Context, NewRHS));
-      }
-    }
-    break;
-      
-  case Instruction::Xor:         // (icmp pred (xor X, XorCST), CI)
-    if (ConstantInt *XorCST = dyn_cast<ConstantInt>(LHSI->getOperand(1))) {
-      // If this is a comparison that tests the signbit (X < 0) or (x > -1),
-      // fold the xor.
-      if ((ICI.getPredicate() == ICmpInst::ICMP_SLT && RHSV == 0) ||
-          (ICI.getPredicate() == ICmpInst::ICMP_SGT && RHSV.isAllOnesValue())) {
-        Value *CompareVal = LHSI->getOperand(0);
-        
-        // If the sign bit of the XorCST is not set, there is no change to
-        // the operation, just stop using the Xor.
-        if (!XorCST->getValue().isNegative()) {
-          ICI.setOperand(0, CompareVal);
-          Worklist.Add(LHSI);
-          return &ICI;
-        }
-        
-        // Was the old condition true if the operand is positive?
-        bool isTrueIfPositive = ICI.getPredicate() == ICmpInst::ICMP_SGT;
-        
-        // If so, the new one isn't.
-        isTrueIfPositive ^= true;
-        
-        if (isTrueIfPositive)
-          return new ICmpInst(ICmpInst::ICMP_SGT, CompareVal,
-                              SubOne(RHS));
-        else
-          return new ICmpInst(ICmpInst::ICMP_SLT, CompareVal,
-                              AddOne(RHS));
-      }
-
-      if (LHSI->hasOneUse()) {
-        // (icmp u/s (xor A SignBit), C) -> (icmp s/u A, (xor C SignBit))
-        if (!ICI.isEquality() && XorCST->getValue().isSignBit()) {
-          const APInt &SignBit = XorCST->getValue();
-          ICmpInst::Predicate Pred = ICI.isSigned()
-                                         ? ICI.getUnsignedPredicate()
-                                         : ICI.getSignedPredicate();
-          return new ICmpInst(Pred, LHSI->getOperand(0),
-                              ConstantInt::get(*Context, RHSV ^ SignBit));
-        }
-
-        // (icmp u/s (xor A ~SignBit), C) -> (icmp s/u (xor C ~SignBit), A)
-        if (!ICI.isEquality() && XorCST->getValue().isMaxSignedValue()) {
-          const APInt &NotSignBit = XorCST->getValue();
-          ICmpInst::Predicate Pred = ICI.isSigned()
-                                         ? ICI.getUnsignedPredicate()
-                                         : ICI.getSignedPredicate();
-          Pred = ICI.getSwappedPredicate(Pred);
-          return new ICmpInst(Pred, LHSI->getOperand(0),
-                              ConstantInt::get(*Context, RHSV ^ NotSignBit));
-        }
-      }
-    }
-    break;
-  case Instruction::And:         // (icmp pred (and X, AndCST), RHS)
-    if (LHSI->hasOneUse() && isa<ConstantInt>(LHSI->getOperand(1)) &&
-        LHSI->getOperand(0)->hasOneUse()) {
-      ConstantInt *AndCST = cast<ConstantInt>(LHSI->getOperand(1));
-      
-      // If the LHS is an AND of a truncating cast, we can widen the
-      // and/compare to be the input width without changing the value
-      // produced, eliminating a cast.
-      if (TruncInst *Cast = dyn_cast<TruncInst>(LHSI->getOperand(0))) {
-        // We can do this transformation if either the AND constant does not
-        // have its sign bit set or if it is an equality comparison. 
-        // Extending a relational comparison when we're checking the sign
-        // bit would not work.
-        if (Cast->hasOneUse() &&
-            (ICI.isEquality() ||
-             (AndCST->getValue().isNonNegative() && RHSV.isNonNegative()))) {
-          uint32_t BitWidth = 
-            cast<IntegerType>(Cast->getOperand(0)->getType())->getBitWidth();
-          APInt NewCST = AndCST->getValue();
-          NewCST.zext(BitWidth);
-          APInt NewCI = RHSV;
-          NewCI.zext(BitWidth);
-          Value *NewAnd = 
-            Builder->CreateAnd(Cast->getOperand(0),
-                           ConstantInt::get(*Context, NewCST), LHSI->getName());
-          return new ICmpInst(ICI.getPredicate(), NewAnd,
-                              ConstantInt::get(*Context, NewCI));
-        }
-      }
-      
-      // If this is: (X >> C1) & C2 != C3 (where any shift and any compare
-      // could exist), turn it into (X & (C2 << C1)) != (C3 << C1).  This
-      // happens a LOT in code produced by the C front-end, for bitfield
-      // access.
-      BinaryOperator *Shift = dyn_cast<BinaryOperator>(LHSI->getOperand(0));
-      if (Shift && !Shift->isShift())
-        Shift = 0;
-      
-      ConstantInt *ShAmt;
-      ShAmt = Shift ? dyn_cast<ConstantInt>(Shift->getOperand(1)) : 0;
-      const Type *Ty = Shift ? Shift->getType() : 0;  // Type of the shift.
-      const Type *AndTy = AndCST->getType();          // Type of the and.
-      
-      // We can fold this as long as we can't shift unknown bits
-      // into the mask.  This can only happen with signed shift
-      // rights, as they sign-extend.
-      if (ShAmt) {
-        bool CanFold = Shift->isLogicalShift();
-        if (!CanFold) {
-          // To test for the bad case of the signed shr, see if any
-          // of the bits shifted in could be tested after the mask.
-          uint32_t TyBits = Ty->getPrimitiveSizeInBits();
-          int ShAmtVal = TyBits - ShAmt->getLimitedValue(TyBits);
-          
-          uint32_t BitWidth = AndTy->getPrimitiveSizeInBits();
-          if ((APInt::getHighBitsSet(BitWidth, BitWidth-ShAmtVal) & 
-               AndCST->getValue()) == 0)
-            CanFold = true;
-        }
-        
-        if (CanFold) {
-          Constant *NewCst;
-          if (Shift->getOpcode() == Instruction::Shl)
-            NewCst = ConstantExpr::getLShr(RHS, ShAmt);
-          else
-            NewCst = ConstantExpr::getShl(RHS, ShAmt);
-          
-          // Check to see if we are shifting out any of the bits being
-          // compared.
-          if (ConstantExpr::get(Shift->getOpcode(),
-                                       NewCst, ShAmt) != RHS) {
-            // If we shifted bits out, the fold is not going to work out.
-            // As a special case, check to see if this means that the
-            // result is always true or false now.
-            if (ICI.getPredicate() == ICmpInst::ICMP_EQ)
-              return ReplaceInstUsesWith(ICI, ConstantInt::getFalse(*Context));
-            if (ICI.getPredicate() == ICmpInst::ICMP_NE)
-              return ReplaceInstUsesWith(ICI, ConstantInt::getTrue(*Context));
-          } else {
-            ICI.setOperand(1, NewCst);
-            Constant *NewAndCST;
-            if (Shift->getOpcode() == Instruction::Shl)
-              NewAndCST = ConstantExpr::getLShr(AndCST, ShAmt);
-            else
-              NewAndCST = ConstantExpr::getShl(AndCST, ShAmt);
-            LHSI->setOperand(1, NewAndCST);
-            LHSI->setOperand(0, Shift->getOperand(0));
-            Worklist.Add(Shift); // Shift is dead.
-            return &ICI;
-          }
-        }
-      }
-      
-      // Turn ((X >> Y) & C) == 0  into  (X & (C << Y)) == 0.  The later is
-      // preferable because it allows the C<<Y expression to be hoisted out
-      // of a loop if Y is invariant and X is not.
-      if (Shift && Shift->hasOneUse() && RHSV == 0 &&
-          ICI.isEquality() && !Shift->isArithmeticShift() &&
-          !isa<Constant>(Shift->getOperand(0))) {
-        // Compute C << Y.
-        Value *NS;
-        if (Shift->getOpcode() == Instruction::LShr) {
-          NS = Builder->CreateShl(AndCST, Shift->getOperand(1), "tmp");
-        } else {
-          // Insert a logical shift.
-          NS = Builder->CreateLShr(AndCST, Shift->getOperand(1), "tmp");
-        }
-        
-        // Compute X & (C << Y).
-        Value *NewAnd = 
-          Builder->CreateAnd(Shift->getOperand(0), NS, LHSI->getName());
-        
-        ICI.setOperand(0, NewAnd);
-        return &ICI;
-      }
-    }
-      
-    // Try to optimize things like "A[i]&42 == 0" to index computations.
-    if (LoadInst *LI = dyn_cast<LoadInst>(LHSI->getOperand(0))) {
-      if (GetElementPtrInst *GEP =
-          dyn_cast<GetElementPtrInst>(LI->getOperand(0)))
-        if (GlobalVariable *GV = dyn_cast<GlobalVariable>(GEP->getOperand(0)))
-          if (GV->isConstant() && GV->hasDefinitiveInitializer() &&
-              !LI->isVolatile() && isa<ConstantInt>(LHSI->getOperand(1))) {
-            ConstantInt *C = cast<ConstantInt>(LHSI->getOperand(1));
-            if (Instruction *Res = FoldCmpLoadFromIndexedGlobal(GEP, GV,ICI, C))
-              return Res;
-          }
-    }
-    break;
-
-  case Instruction::Or: {
-    if (!ICI.isEquality() || !RHS->isNullValue() || !LHSI->hasOneUse())
-      break;
-    Value *P, *Q;
-    if (match(LHSI, m_Or(m_PtrToInt(m_Value(P)), m_PtrToInt(m_Value(Q))))) {
-      // Simplify icmp eq (or (ptrtoint P), (ptrtoint Q)), 0
-      // -> and (icmp eq P, null), (icmp eq Q, null).
-
-      Value *ICIP = Builder->CreateICmp(ICI.getPredicate(), P,
-                                        Constant::getNullValue(P->getType()));
-      Value *ICIQ = Builder->CreateICmp(ICI.getPredicate(), Q,
-                                        Constant::getNullValue(Q->getType()));
-      Instruction *Op;
-      if (ICI.getPredicate() == ICmpInst::ICMP_EQ)
-        Op = BinaryOperator::CreateAnd(ICIP, ICIQ);
-      else
-        Op = BinaryOperator::CreateOr(ICIP, ICIQ);
-      return Op;
-    }
-    break;
-  }
-    
-  case Instruction::Shl: {       // (icmp pred (shl X, ShAmt), CI)
-    ConstantInt *ShAmt = dyn_cast<ConstantInt>(LHSI->getOperand(1));
-    if (!ShAmt) break;
-    
-    uint32_t TypeBits = RHSV.getBitWidth();
-    
-    // Check that the shift amount is in range.  If not, don't perform
-    // undefined shifts.  When the shift is visited it will be
-    // simplified.
-    if (ShAmt->uge(TypeBits))
-      break;
-    
-    if (ICI.isEquality()) {
-      // If we are comparing against bits always shifted out, the
-      // comparison cannot succeed.
-      Constant *Comp =
-        ConstantExpr::getShl(ConstantExpr::getLShr(RHS, ShAmt),
-                                                                 ShAmt);
-      if (Comp != RHS) {// Comparing against a bit that we know is zero.
-        bool IsICMP_NE = ICI.getPredicate() == ICmpInst::ICMP_NE;
-        Constant *Cst = ConstantInt::get(Type::getInt1Ty(*Context), IsICMP_NE);
-        return ReplaceInstUsesWith(ICI, Cst);
-      }
-      
-      if (LHSI->hasOneUse()) {
-        // Otherwise strength reduce the shift into an and.
-        uint32_t ShAmtVal = (uint32_t)ShAmt->getLimitedValue(TypeBits);
-        Constant *Mask =
-          ConstantInt::get(*Context, APInt::getLowBitsSet(TypeBits, 
-                                                       TypeBits-ShAmtVal));
-        
-        Value *And =
-          Builder->CreateAnd(LHSI->getOperand(0),Mask, LHSI->getName()+".mask");
-        return new ICmpInst(ICI.getPredicate(), And,
-                            ConstantInt::get(*Context, RHSV.lshr(ShAmtVal)));
-      }
-    }
-    
-    // Otherwise, if this is a comparison of the sign bit, simplify to and/test.
-    bool TrueIfSigned = false;
-    if (LHSI->hasOneUse() &&
-        isSignBitCheck(ICI.getPredicate(), RHS, TrueIfSigned)) {
-      // (X << 31) <s 0  --> (X&1) != 0
-      Constant *Mask = ConstantInt::get(*Context, APInt(TypeBits, 1) <<
-                                           (TypeBits-ShAmt->getZExtValue()-1));
-      Value *And =
-        Builder->CreateAnd(LHSI->getOperand(0), Mask, LHSI->getName()+".mask");
-      return new ICmpInst(TrueIfSigned ? ICmpInst::ICMP_NE : ICmpInst::ICMP_EQ,
-                          And, Constant::getNullValue(And->getType()));
-    }
-    break;
-  }
-    
-  case Instruction::LShr:         // (icmp pred (shr X, ShAmt), CI)
-  case Instruction::AShr: {
-    // Only handle equality comparisons of shift-by-constant.
-    ConstantInt *ShAmt = dyn_cast<ConstantInt>(LHSI->getOperand(1));
-    if (!ShAmt || !ICI.isEquality()) break;
-
-    // Check that the shift amount is in range.  If not, don't perform
-    // undefined shifts.  When the shift is visited it will be
-    // simplified.
-    uint32_t TypeBits = RHSV.getBitWidth();
-    if (ShAmt->uge(TypeBits))
-      break;
-    
-    uint32_t ShAmtVal = (uint32_t)ShAmt->getLimitedValue(TypeBits);
-      
-    // If we are comparing against bits always shifted out, the
-    // comparison cannot succeed.
-    APInt Comp = RHSV << ShAmtVal;
-    if (LHSI->getOpcode() == Instruction::LShr)
-      Comp = Comp.lshr(ShAmtVal);
-    else
-      Comp = Comp.ashr(ShAmtVal);
-    
-    if (Comp != RHSV) { // Comparing against a bit that we know is zero.
-      bool IsICMP_NE = ICI.getPredicate() == ICmpInst::ICMP_NE;
-      Constant *Cst = ConstantInt::get(Type::getInt1Ty(*Context), IsICMP_NE);
-      return ReplaceInstUsesWith(ICI, Cst);
-    }
-    
-    // Otherwise, check to see if the bits shifted out are known to be zero.
-    // If so, we can compare against the unshifted value:
-    //  (X & 4) >> 1 == 2  --> (X & 4) == 4.
-    if (LHSI->hasOneUse() &&
-        MaskedValueIsZero(LHSI->getOperand(0), 
-                          APInt::getLowBitsSet(Comp.getBitWidth(), ShAmtVal))) {
-      return new ICmpInst(ICI.getPredicate(), LHSI->getOperand(0),
-                          ConstantExpr::getShl(RHS, ShAmt));
-    }
-      
-    if (LHSI->hasOneUse()) {
-      // Otherwise strength reduce the shift into an and.
-      APInt Val(APInt::getHighBitsSet(TypeBits, TypeBits - ShAmtVal));
-      Constant *Mask = ConstantInt::get(*Context, Val);
-      
-      Value *And = Builder->CreateAnd(LHSI->getOperand(0),
-                                      Mask, LHSI->getName()+".mask");
-      return new ICmpInst(ICI.getPredicate(), And,
-                          ConstantExpr::getShl(RHS, ShAmt));
-    }
-    break;
-  }
-    
-  case Instruction::SDiv:
-  case Instruction::UDiv:
-    // Fold: icmp pred ([us]div X, C1), C2 -> range test
-    // Fold this div into the comparison, producing a range check. 
-    // Determine, based on the divide type, what the range is being 
-    // checked.  If there is an overflow on the low or high side, remember 
-    // it, otherwise compute the range [low, hi) bounding the new value.
-    // See: InsertRangeTest above for the kinds of replacements possible.
-    if (ConstantInt *DivRHS = dyn_cast<ConstantInt>(LHSI->getOperand(1)))
-      if (Instruction *R = FoldICmpDivCst(ICI, cast<BinaryOperator>(LHSI),
-                                          DivRHS))
-        return R;
-    break;
-
-  case Instruction::Add:
-    // Fold: icmp pred (add X, C1), C2
-    if (!ICI.isEquality()) {
-      ConstantInt *LHSC = dyn_cast<ConstantInt>(LHSI->getOperand(1));
-      if (!LHSC) break;
-      const APInt &LHSV = LHSC->getValue();
-
-      ConstantRange CR = ICI.makeConstantRange(ICI.getPredicate(), RHSV)
-                            .subtract(LHSV);
-
-      if (ICI.isSigned()) {
-        if (CR.getLower().isSignBit()) {
-          return new ICmpInst(ICmpInst::ICMP_SLT, LHSI->getOperand(0),
-                              ConstantInt::get(*Context, CR.getUpper()));
-        } else if (CR.getUpper().isSignBit()) {
-          return new ICmpInst(ICmpInst::ICMP_SGE, LHSI->getOperand(0),
-                              ConstantInt::get(*Context, CR.getLower()));
-        }
-      } else {
-        if (CR.getLower().isMinValue()) {
-          return new ICmpInst(ICmpInst::ICMP_ULT, LHSI->getOperand(0),
-                              ConstantInt::get(*Context, CR.getUpper()));
-        } else if (CR.getUpper().isMinValue()) {
-          return new ICmpInst(ICmpInst::ICMP_UGE, LHSI->getOperand(0),
-                              ConstantInt::get(*Context, CR.getLower()));
-        }
-      }
-    }
-    break;
-  }
-  
-  // Simplify icmp_eq and icmp_ne instructions with integer constant RHS.
-  if (ICI.isEquality()) {
-    bool isICMP_NE = ICI.getPredicate() == ICmpInst::ICMP_NE;
-    
-    // If the first operand is (add|sub|and|or|xor|rem) with a constant, and 
-    // the second operand is a constant, simplify a bit.
-    if (BinaryOperator *BO = dyn_cast<BinaryOperator>(LHSI)) {
-      switch (BO->getOpcode()) {
-      case Instruction::SRem:
-        // If we have a signed (X % (2^c)) == 0, turn it into an unsigned one.
-        if (RHSV == 0 && isa<ConstantInt>(BO->getOperand(1)) &&BO->hasOneUse()){
-          const APInt &V = cast<ConstantInt>(BO->getOperand(1))->getValue();
-          if (V.sgt(APInt(V.getBitWidth(), 1)) && V.isPowerOf2()) {
-            Value *NewRem =
-              Builder->CreateURem(BO->getOperand(0), BO->getOperand(1),
-                                  BO->getName());
-            return new ICmpInst(ICI.getPredicate(), NewRem,
-                                Constant::getNullValue(BO->getType()));
-          }
-        }
-        break;
-      case Instruction::Add:
-        // Replace ((add A, B) != C) with (A != C-B) if B & C are constants.
-        if (ConstantInt *BOp1C = dyn_cast<ConstantInt>(BO->getOperand(1))) {
-          if (BO->hasOneUse())
-            return new ICmpInst(ICI.getPredicate(), BO->getOperand(0),
-                                ConstantExpr::getSub(RHS, BOp1C));
-        } else if (RHSV == 0) {
-          // Replace ((add A, B) != 0) with (A != -B) if A or B is
-          // efficiently invertible, or if the add has just this one use.
-          Value *BOp0 = BO->getOperand(0), *BOp1 = BO->getOperand(1);
-          
-          if (Value *NegVal = dyn_castNegVal(BOp1))
-            return new ICmpInst(ICI.getPredicate(), BOp0, NegVal);
-          else if (Value *NegVal = dyn_castNegVal(BOp0))
-            return new ICmpInst(ICI.getPredicate(), NegVal, BOp1);
-          else if (BO->hasOneUse()) {
-            Value *Neg = Builder->CreateNeg(BOp1);
-            Neg->takeName(BO);
-            return new ICmpInst(ICI.getPredicate(), BOp0, Neg);
-          }
-        }
-        break;
-      case Instruction::Xor:
-        // For the xor case, we can xor two constants together, eliminating
-        // the explicit xor.
-        if (Constant *BOC = dyn_cast<Constant>(BO->getOperand(1)))
-          return new ICmpInst(ICI.getPredicate(), BO->getOperand(0), 
-                              ConstantExpr::getXor(RHS, BOC));
-        
-        // FALLTHROUGH
-      case Instruction::Sub:
-        // Replace (([sub|xor] A, B) != 0) with (A != B)
-        if (RHSV == 0)
-          return new ICmpInst(ICI.getPredicate(), BO->getOperand(0),
-                              BO->getOperand(1));
-        break;
-        
-      case Instruction::Or:
-        // If bits are being or'd in that are not present in the constant we
-        // are comparing against, then the comparison could never succeed!
-        if (Constant *BOC = dyn_cast<Constant>(BO->getOperand(1))) {
-          Constant *NotCI = ConstantExpr::getNot(RHS);
-          if (!ConstantExpr::getAnd(BOC, NotCI)->isNullValue())
-            return ReplaceInstUsesWith(ICI,
-                                       ConstantInt::get(Type::getInt1Ty(*Context), 
-                                       isICMP_NE));
-        }
-        break;
-        
-      case Instruction::And:
-        if (ConstantInt *BOC = dyn_cast<ConstantInt>(BO->getOperand(1))) {
-          // If bits are being compared against that are and'd out, then the
-          // comparison can never succeed!
-          if ((RHSV & ~BOC->getValue()) != 0)
-            return ReplaceInstUsesWith(ICI,
-                                       ConstantInt::get(Type::getInt1Ty(*Context),
-                                       isICMP_NE));
-          
-          // If we have ((X & C) == C), turn it into ((X & C) != 0).
-          if (RHS == BOC && RHSV.isPowerOf2())
-            return new ICmpInst(isICMP_NE ? ICmpInst::ICMP_EQ :
-                                ICmpInst::ICMP_NE, LHSI,
-                                Constant::getNullValue(RHS->getType()));
-          
-          // Replace (and X, (1 << size(X)-1) != 0) with x s< 0
-          if (BOC->getValue().isSignBit()) {
-            Value *X = BO->getOperand(0);
-            Constant *Zero = Constant::getNullValue(X->getType());
-            ICmpInst::Predicate pred = isICMP_NE ? 
-              ICmpInst::ICMP_SLT : ICmpInst::ICMP_SGE;
-            return new ICmpInst(pred, X, Zero);
-          }
-          
-          // ((X & ~7) == 0) --> X < 8
-          if (RHSV == 0 && isHighOnes(BOC)) {
-            Value *X = BO->getOperand(0);
-            Constant *NegX = ConstantExpr::getNeg(BOC);
-            ICmpInst::Predicate pred = isICMP_NE ? 
-              ICmpInst::ICMP_UGE : ICmpInst::ICMP_ULT;
-            return new ICmpInst(pred, X, NegX);
-          }
-        }
-      default: break;
-      }
-    } else if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(LHSI)) {
-      // Handle icmp {eq|ne} <intrinsic>, intcst.
-      if (II->getIntrinsicID() == Intrinsic::bswap) {
-        Worklist.Add(II);
-        ICI.setOperand(0, II->getOperand(1));
-        ICI.setOperand(1, ConstantInt::get(*Context, RHSV.byteSwap()));
-        return &ICI;
-      }
-    }
-  }
-  return 0;
-}
-
-/// visitICmpInstWithCastAndCast - Handle icmp (cast x to y), (cast/cst).
-/// We only handle extending casts so far.
-///
-Instruction *InstCombiner::visitICmpInstWithCastAndCast(ICmpInst &ICI) {
-  const CastInst *LHSCI = cast<CastInst>(ICI.getOperand(0));
-  Value *LHSCIOp        = LHSCI->getOperand(0);
-  const Type *SrcTy     = LHSCIOp->getType();
-  const Type *DestTy    = LHSCI->getType();
-  Value *RHSCIOp;
-
-  // Turn icmp (ptrtoint x), (ptrtoint/c) into a compare of the input if the 
-  // integer type is the same size as the pointer type.
-  if (TD && LHSCI->getOpcode() == Instruction::PtrToInt &&
-      TD->getPointerSizeInBits() ==
-         cast<IntegerType>(DestTy)->getBitWidth()) {
-    Value *RHSOp = 0;
-    if (Constant *RHSC = dyn_cast<Constant>(ICI.getOperand(1))) {
-      RHSOp = ConstantExpr::getIntToPtr(RHSC, SrcTy);
-    } else if (PtrToIntInst *RHSC = dyn_cast<PtrToIntInst>(ICI.getOperand(1))) {
-      RHSOp = RHSC->getOperand(0);
-      // If the pointer types don't match, insert a bitcast.
-      if (LHSCIOp->getType() != RHSOp->getType())
-        RHSOp = Builder->CreateBitCast(RHSOp, LHSCIOp->getType());
-    }
-
-    if (RHSOp)
-      return new ICmpInst(ICI.getPredicate(), LHSCIOp, RHSOp);
-  }
-  
-  // The code below only handles extension cast instructions, so far.
-  // Enforce this.
-  if (LHSCI->getOpcode() != Instruction::ZExt &&
-      LHSCI->getOpcode() != Instruction::SExt)
-    return 0;
-
-  bool isSignedExt = LHSCI->getOpcode() == Instruction::SExt;
-  bool isSignedCmp = ICI.isSigned();
-
-  if (CastInst *CI = dyn_cast<CastInst>(ICI.getOperand(1))) {
-    // Not an extension from the same type?
-    RHSCIOp = CI->getOperand(0);
-    if (RHSCIOp->getType() != LHSCIOp->getType()) 
-      return 0;
-    
-    // If the signedness of the two casts doesn't agree (i.e. one is a sext
-    // and the other is a zext), then we can't handle this.
-    if (CI->getOpcode() != LHSCI->getOpcode())
-      return 0;
-
-    // Deal with equality cases early.
-    if (ICI.isEquality())
-      return new ICmpInst(ICI.getPredicate(), LHSCIOp, RHSCIOp);
-
-    // A signed comparison of sign extended values simplifies into a
-    // signed comparison.
-    if (isSignedCmp && isSignedExt)
-      return new ICmpInst(ICI.getPredicate(), LHSCIOp, RHSCIOp);
-
-    // The other three cases all fold into an unsigned comparison.
-    return new ICmpInst(ICI.getUnsignedPredicate(), LHSCIOp, RHSCIOp);
-  }
-
-  // If we aren't dealing with a constant on the RHS, exit early
-  ConstantInt *CI = dyn_cast<ConstantInt>(ICI.getOperand(1));
-  if (!CI)
-    return 0;
-
-  // Compute the constant that would happen if we truncated to SrcTy then
-  // reextended to DestTy.
-  Constant *Res1 = ConstantExpr::getTrunc(CI, SrcTy);
-  Constant *Res2 = ConstantExpr::getCast(LHSCI->getOpcode(),
-                                                Res1, DestTy);
-
-  // If the re-extended constant didn't change...
-  if (Res2 == CI) {
-    // Deal with equality cases early.
-    if (ICI.isEquality())
-      return new ICmpInst(ICI.getPredicate(), LHSCIOp, Res1);
-
-    // A signed comparison of sign extended values simplifies into a
-    // signed comparison.
-    if (isSignedExt && isSignedCmp)
-      return new ICmpInst(ICI.getPredicate(), LHSCIOp, Res1);
-
-    // The other three cases all fold into an unsigned comparison.
-    return new ICmpInst(ICI.getUnsignedPredicate(), LHSCIOp, Res1);
-  }
-
-  // The re-extended constant changed so the constant cannot be represented 
-  // in the shorter type. Consequently, we cannot emit a simple comparison.
-
-  // First, handle some easy cases. We know the result cannot be equal at this
-  // point so handle the ICI.isEquality() cases
-  if (ICI.getPredicate() == ICmpInst::ICMP_EQ)
-    return ReplaceInstUsesWith(ICI, ConstantInt::getFalse(*Context));
-  if (ICI.getPredicate() == ICmpInst::ICMP_NE)
-    return ReplaceInstUsesWith(ICI, ConstantInt::getTrue(*Context));
-
-  // Evaluate the comparison for LT (we invert for GT below). LE and GE cases
-  // should have been folded away previously and not enter in here.
-  Value *Result;
-  if (isSignedCmp) {
-    // We're performing a signed comparison.
-    if (cast<ConstantInt>(CI)->getValue().isNegative())
-      Result = ConstantInt::getFalse(*Context);          // X < (small) --> false
-    else
-      Result = ConstantInt::getTrue(*Context);           // X < (large) --> true
-  } else {
-    // We're performing an unsigned comparison.
-    if (isSignedExt) {
-      // We're performing an unsigned comp with a sign extended value.
-      // This is true if the input is >= 0. [aka >s -1]
-      Constant *NegOne = Constant::getAllOnesValue(SrcTy);
-      Result = Builder->CreateICmpSGT(LHSCIOp, NegOne, ICI.getName());
-    } else {
-      // Unsigned extend & unsigned compare -> always true.
-      Result = ConstantInt::getTrue(*Context);
-    }
-  }
-
-  // Finally, return the value computed.
-  if (ICI.getPredicate() == ICmpInst::ICMP_ULT ||
-      ICI.getPredicate() == ICmpInst::ICMP_SLT)
-    return ReplaceInstUsesWith(ICI, Result);
-
-  assert((ICI.getPredicate()==ICmpInst::ICMP_UGT || 
-          ICI.getPredicate()==ICmpInst::ICMP_SGT) &&
-         "ICmp should be folded!");
-  if (Constant *CI = dyn_cast<Constant>(Result))
-    return ReplaceInstUsesWith(ICI, ConstantExpr::getNot(CI));
-  return BinaryOperator::CreateNot(Result);
-}
-
-Instruction *InstCombiner::visitShl(BinaryOperator &I) {
-  return commonShiftTransforms(I);
-}
-
-Instruction *InstCombiner::visitLShr(BinaryOperator &I) {
-  return commonShiftTransforms(I);
-}
-
-Instruction *InstCombiner::visitAShr(BinaryOperator &I) {
-  if (Instruction *R = commonShiftTransforms(I))
-    return R;
-  
-  Value *Op0 = I.getOperand(0);
-  
-  // ashr int -1, X = -1   (for any arithmetic shift rights of ~0)
-  if (ConstantInt *CSI = dyn_cast<ConstantInt>(Op0))
-    if (CSI->isAllOnesValue())
-      return ReplaceInstUsesWith(I, CSI);
-
-  // See if we can turn a signed shr into an unsigned shr.
-  if (MaskedValueIsZero(Op0,
-                        APInt::getSignBit(I.getType()->getScalarSizeInBits())))
-    return BinaryOperator::CreateLShr(Op0, I.getOperand(1));
-
-  // Arithmetic shifting an all-sign-bit value is a no-op.
-  unsigned NumSignBits = ComputeNumSignBits(Op0);
-  if (NumSignBits == Op0->getType()->getScalarSizeInBits())
-    return ReplaceInstUsesWith(I, Op0);
-
-  return 0;
-}
-
-Instruction *InstCombiner::commonShiftTransforms(BinaryOperator &I) {
-  assert(I.getOperand(1)->getType() == I.getOperand(0)->getType());
-  Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
-
-  // shl X, 0 == X and shr X, 0 == X
-  // shl 0, X == 0 and shr 0, X == 0
-  if (Op1 == Constant::getNullValue(Op1->getType()) ||
-      Op0 == Constant::getNullValue(Op0->getType()))
-    return ReplaceInstUsesWith(I, Op0);
-  
-  if (isa<UndefValue>(Op0)) {            
-    if (I.getOpcode() == Instruction::AShr) // undef >>s X -> undef
-      return ReplaceInstUsesWith(I, Op0);
-    else                                    // undef << X -> 0, undef >>u X -> 0
-      return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
-  }
-  if (isa<UndefValue>(Op1)) {
-    if (I.getOpcode() == Instruction::AShr)  // X >>s undef -> X
-      return ReplaceInstUsesWith(I, Op0);          
-    else                                     // X << undef, X >>u undef -> 0
-      return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
-  }
-
-  // See if we can fold away this shift.
-  if (SimplifyDemandedInstructionBits(I))
-    return &I;
-
-  // Try to fold constant and into select arguments.
-  if (isa<Constant>(Op0))
-    if (SelectInst *SI = dyn_cast<SelectInst>(Op1))
-      if (Instruction *R = FoldOpIntoSelect(I, SI, this))
-        return R;
-
-  if (ConstantInt *CUI = dyn_cast<ConstantInt>(Op1))
-    if (Instruction *Res = FoldShiftByConstant(Op0, CUI, I))
-      return Res;
-  return 0;
-}
-
-Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, ConstantInt *Op1,
-                                               BinaryOperator &I) {
-  bool isLeftShift = I.getOpcode() == Instruction::Shl;
-
-  // See if we can simplify any instructions used by the instruction whose sole 
-  // purpose is to compute bits we don't care about.
-  uint32_t TypeBits = Op0->getType()->getScalarSizeInBits();
-  
-  // shl i32 X, 32 = 0 and srl i8 Y, 9 = 0, ... just don't eliminate
-  // a signed shift.
-  //
-  if (Op1->uge(TypeBits)) {
-    if (I.getOpcode() != Instruction::AShr)
-      return ReplaceInstUsesWith(I, Constant::getNullValue(Op0->getType()));
-    else {
-      I.setOperand(1, ConstantInt::get(I.getType(), TypeBits-1));
-      return &I;
-    }
-  }
-  
-  // ((X*C1) << C2) == (X * (C1 << C2))
-  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(Op0))
-    if (BO->getOpcode() == Instruction::Mul && isLeftShift)
-      if (Constant *BOOp = dyn_cast<Constant>(BO->getOperand(1)))
-        return BinaryOperator::CreateMul(BO->getOperand(0),
-                                        ConstantExpr::getShl(BOOp, Op1));
-  
-  // Try to fold constant and into select arguments.
-  if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
-    if (Instruction *R = FoldOpIntoSelect(I, SI, this))
-      return R;
-  if (isa<PHINode>(Op0))
-    if (Instruction *NV = FoldOpIntoPhi(I))
-      return NV;
-  
-  // Fold shift2(trunc(shift1(x,c1)), c2) -> trunc(shift2(shift1(x,c1),c2))
-  if (TruncInst *TI = dyn_cast<TruncInst>(Op0)) {
-    Instruction *TrOp = dyn_cast<Instruction>(TI->getOperand(0));
-    // If 'shift2' is an ashr, we would have to get the sign bit into a funny
-    // place.  Don't try to do this transformation in this case.  Also, we
-    // require that the input operand is a shift-by-constant so that we have
-    // confidence that the shifts will get folded together.  We could do this
-    // xform in more cases, but it is unlikely to be profitable.
-    if (TrOp && I.isLogicalShift() && TrOp->isShift() && 
-        isa<ConstantInt>(TrOp->getOperand(1))) {
-      // Okay, we'll do this xform.  Make the shift of shift.
-      Constant *ShAmt = ConstantExpr::getZExt(Op1, TrOp->getType());
-      // (shift2 (shift1 & 0x00FF), c2)
-      Value *NSh = Builder->CreateBinOp(I.getOpcode(), TrOp, ShAmt,I.getName());
-
-      // For logical shifts, the truncation has the effect of making the high
-      // part of the register be zeros.  Emulate this by inserting an AND to
-      // clear the top bits as needed.  This 'and' will usually be zapped by
-      // other xforms later if dead.
-      unsigned SrcSize = TrOp->getType()->getScalarSizeInBits();
-      unsigned DstSize = TI->getType()->getScalarSizeInBits();
-      APInt MaskV(APInt::getLowBitsSet(SrcSize, DstSize));
-      
-      // The mask we constructed says what the trunc would do if occurring
-      // between the shifts.  We want to know the effect *after* the second
-      // shift.  We know that it is a logical shift by a constant, so adjust the
-      // mask as appropriate.
-      if (I.getOpcode() == Instruction::Shl)
-        MaskV <<= Op1->getZExtValue();
-      else {
-        assert(I.getOpcode() == Instruction::LShr && "Unknown logical shift");
-        MaskV = MaskV.lshr(Op1->getZExtValue());
-      }
-
-      // shift1 & 0x00FF
-      Value *And = Builder->CreateAnd(NSh, ConstantInt::get(*Context, MaskV),
-                                      TI->getName());
-
-      // Return the value truncated to the interesting size.
-      return new TruncInst(And, I.getType());
-    }
-  }
-  
-  if (Op0->hasOneUse()) {
-    if (BinaryOperator *Op0BO = dyn_cast<BinaryOperator>(Op0)) {
-      // Turn ((X >> C) + Y) << C  ->  (X + (Y << C)) & (~0 << C)
-      Value *V1, *V2;
-      ConstantInt *CC;
-      switch (Op0BO->getOpcode()) {
-        default: break;
-        case Instruction::Add:
-        case Instruction::And:
-        case Instruction::Or:
-        case Instruction::Xor: {
-          // These operators commute.
-          // Turn (Y + (X >> C)) << C  ->  (X + (Y << C)) & (~0 << C)
-          if (isLeftShift && Op0BO->getOperand(1)->hasOneUse() &&
-              match(Op0BO->getOperand(1), m_Shr(m_Value(V1),
-                    m_Specific(Op1)))) {
-            Value *YS =         // (Y << C)
-              Builder->CreateShl(Op0BO->getOperand(0), Op1, Op0BO->getName());
-            // (X + (Y << C))
-            Value *X = Builder->CreateBinOp(Op0BO->getOpcode(), YS, V1,
-                                            Op0BO->getOperand(1)->getName());
-            uint32_t Op1Val = Op1->getLimitedValue(TypeBits);
-            return BinaryOperator::CreateAnd(X, ConstantInt::get(*Context,
-                       APInt::getHighBitsSet(TypeBits, TypeBits-Op1Val)));
-          }
-          
-          // Turn (Y + ((X >> C) & CC)) << C  ->  ((X & (CC << C)) + (Y << C))
-          Value *Op0BOOp1 = Op0BO->getOperand(1);
-          if (isLeftShift && Op0BOOp1->hasOneUse() &&
-              match(Op0BOOp1, 
-                    m_And(m_Shr(m_Value(V1), m_Specific(Op1)),
-                          m_ConstantInt(CC))) &&
-              cast<BinaryOperator>(Op0BOOp1)->getOperand(0)->hasOneUse()) {
-            Value *YS =   // (Y << C)
-              Builder->CreateShl(Op0BO->getOperand(0), Op1,
-                                           Op0BO->getName());
-            // X & (CC << C)
-            Value *XM = Builder->CreateAnd(V1, ConstantExpr::getShl(CC, Op1),
-                                           V1->getName()+".mask");
-            return BinaryOperator::Create(Op0BO->getOpcode(), YS, XM);
-          }
-        }
-          
-        // FALL THROUGH.
-        case Instruction::Sub: {
-          // Turn ((X >> C) + Y) << C  ->  (X + (Y << C)) & (~0 << C)
-          if (isLeftShift && Op0BO->getOperand(0)->hasOneUse() &&
-              match(Op0BO->getOperand(0), m_Shr(m_Value(V1),
-                    m_Specific(Op1)))) {
-            Value *YS =  // (Y << C)
-              Builder->CreateShl(Op0BO->getOperand(1), Op1, Op0BO->getName());
-            // (X + (Y << C))
-            Value *X = Builder->CreateBinOp(Op0BO->getOpcode(), V1, YS,
-                                            Op0BO->getOperand(0)->getName());
-            uint32_t Op1Val = Op1->getLimitedValue(TypeBits);
-            return BinaryOperator::CreateAnd(X, ConstantInt::get(*Context,
-                       APInt::getHighBitsSet(TypeBits, TypeBits-Op1Val)));
-          }
-          
-          // Turn (((X >> C)&CC) + Y) << C  ->  (X + (Y << C)) & (CC << C)
-          if (isLeftShift && Op0BO->getOperand(0)->hasOneUse() &&
-              match(Op0BO->getOperand(0),
-                    m_And(m_Shr(m_Value(V1), m_Value(V2)),
-                          m_ConstantInt(CC))) && V2 == Op1 &&
-              cast<BinaryOperator>(Op0BO->getOperand(0))
-                  ->getOperand(0)->hasOneUse()) {
-            Value *YS = // (Y << C)
-              Builder->CreateShl(Op0BO->getOperand(1), Op1, Op0BO->getName());
-            // X & (CC << C)
-            Value *XM = Builder->CreateAnd(V1, ConstantExpr::getShl(CC, Op1),
-                                           V1->getName()+".mask");
-            
-            return BinaryOperator::Create(Op0BO->getOpcode(), XM, YS);
-          }
-          
-          break;
-        }
-      }
-      
-      
-      // If the operand is an bitwise operator with a constant RHS, and the
-      // shift is the only use, we can pull it out of the shift.
-      if (ConstantInt *Op0C = dyn_cast<ConstantInt>(Op0BO->getOperand(1))) {
-        bool isValid = true;     // Valid only for And, Or, Xor
-        bool highBitSet = false; // Transform if high bit of constant set?
-        
-        switch (Op0BO->getOpcode()) {
-          default: isValid = false; break;   // Do not perform transform!
-          case Instruction::Add:
-            isValid = isLeftShift;
-            break;
-          case Instruction::Or:
-          case Instruction::Xor:
-            highBitSet = false;
-            break;
-          case Instruction::And:
-            highBitSet = true;
-            break;
-        }
-        
-        // If this is a signed shift right, and the high bit is modified
-        // by the logical operation, do not perform the transformation.
-        // The highBitSet boolean indicates the value of the high bit of
-        // the constant which would cause it to be modified for this
-        // operation.
-        //
-        if (isValid && I.getOpcode() == Instruction::AShr)
-          isValid = Op0C->getValue()[TypeBits-1] == highBitSet;
-        
-        if (isValid) {
-          Constant *NewRHS = ConstantExpr::get(I.getOpcode(), Op0C, Op1);
-          
-          Value *NewShift =
-            Builder->CreateBinOp(I.getOpcode(), Op0BO->getOperand(0), Op1);
-          NewShift->takeName(Op0BO);
-          
-          return BinaryOperator::Create(Op0BO->getOpcode(), NewShift,
-                                        NewRHS);
-        }
-      }
-    }
-  }
-  
-  // Find out if this is a shift of a shift by a constant.
-  BinaryOperator *ShiftOp = dyn_cast<BinaryOperator>(Op0);
-  if (ShiftOp && !ShiftOp->isShift())
-    ShiftOp = 0;
-  
-  if (ShiftOp && isa<ConstantInt>(ShiftOp->getOperand(1))) {
-    ConstantInt *ShiftAmt1C = cast<ConstantInt>(ShiftOp->getOperand(1));
-    uint32_t ShiftAmt1 = ShiftAmt1C->getLimitedValue(TypeBits);
-    uint32_t ShiftAmt2 = Op1->getLimitedValue(TypeBits);
-    assert(ShiftAmt2 != 0 && "Should have been simplified earlier");
-    if (ShiftAmt1 == 0) return 0;  // Will be simplified in the future.
-    Value *X = ShiftOp->getOperand(0);
-    
-    uint32_t AmtSum = ShiftAmt1+ShiftAmt2;   // Fold into one big shift.
-    
-    const IntegerType *Ty = cast<IntegerType>(I.getType());
-    
-    // Check for (X << c1) << c2  and  (X >> c1) >> c2
-    if (I.getOpcode() == ShiftOp->getOpcode()) {
-      // If this is oversized composite shift, then unsigned shifts get 0, ashr
-      // saturates.
-      if (AmtSum >= TypeBits) {
-        if (I.getOpcode() != Instruction::AShr)
-          return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
-        AmtSum = TypeBits-1;  // Saturate to 31 for i32 ashr.
-      }
-      
-      return BinaryOperator::Create(I.getOpcode(), X,
-                                    ConstantInt::get(Ty, AmtSum));
-    }
-    
-    if (ShiftOp->getOpcode() == Instruction::LShr &&
-        I.getOpcode() == Instruction::AShr) {
-      if (AmtSum >= TypeBits)
-        return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
-      
-      // ((X >>u C1) >>s C2) -> (X >>u (C1+C2))  since C1 != 0.
-      return BinaryOperator::CreateLShr(X, ConstantInt::get(Ty, AmtSum));
-    }
-    
-    if (ShiftOp->getOpcode() == Instruction::AShr &&
-        I.getOpcode() == Instruction::LShr) {
-      // ((X >>s C1) >>u C2) -> ((X >>s (C1+C2)) & mask) since C1 != 0.
-      if (AmtSum >= TypeBits)
-        AmtSum = TypeBits-1;
-      
-      Value *Shift = Builder->CreateAShr(X, ConstantInt::get(Ty, AmtSum));
-
-      APInt Mask(APInt::getLowBitsSet(TypeBits, TypeBits - ShiftAmt2));
-      return BinaryOperator::CreateAnd(Shift, ConstantInt::get(*Context, Mask));
-    }
-    
-    // Okay, if we get here, one shift must be left, and the other shift must be
-    // right.  See if the amounts are equal.
-    if (ShiftAmt1 == ShiftAmt2) {
-      // If we have ((X >>? C) << C), turn this into X & (-1 << C).
-      if (I.getOpcode() == Instruction::Shl) {
-        APInt Mask(APInt::getHighBitsSet(TypeBits, TypeBits - ShiftAmt1));
-        return BinaryOperator::CreateAnd(X, ConstantInt::get(*Context, Mask));
-      }
-      // If we have ((X << C) >>u C), turn this into X & (-1 >>u C).
-      if (I.getOpcode() == Instruction::LShr) {
-        APInt Mask(APInt::getLowBitsSet(TypeBits, TypeBits - ShiftAmt1));
-        return BinaryOperator::CreateAnd(X, ConstantInt::get(*Context, Mask));
-      }
-      // We can simplify ((X << C) >>s C) into a trunc + sext.
-      // NOTE: we could do this for any C, but that would make 'unusual' integer
-      // types.  For now, just stick to ones well-supported by the code
-      // generators.
-      const Type *SExtType = 0;
-      switch (Ty->getBitWidth() - ShiftAmt1) {
-      case 1  :
-      case 8  :
-      case 16 :
-      case 32 :
-      case 64 :
-      case 128:
-        SExtType = IntegerType::get(*Context, Ty->getBitWidth() - ShiftAmt1);
-        break;
-      default: break;
-      }
-      if (SExtType)
-        return new SExtInst(Builder->CreateTrunc(X, SExtType, "sext"), Ty);
-      // Otherwise, we can't handle it yet.
-    } else if (ShiftAmt1 < ShiftAmt2) {
-      uint32_t ShiftDiff = ShiftAmt2-ShiftAmt1;
-      
-      // (X >>? C1) << C2 --> X << (C2-C1) & (-1 << C2)
-      if (I.getOpcode() == Instruction::Shl) {
-        assert(ShiftOp->getOpcode() == Instruction::LShr ||
-               ShiftOp->getOpcode() == Instruction::AShr);
-        Value *Shift = Builder->CreateShl(X, ConstantInt::get(Ty, ShiftDiff));
-        
-        APInt Mask(APInt::getHighBitsSet(TypeBits, TypeBits - ShiftAmt2));
-        return BinaryOperator::CreateAnd(Shift,
-                                         ConstantInt::get(*Context, Mask));
-      }
-      
-      // (X << C1) >>u C2  --> X >>u (C2-C1) & (-1 >> C2)
-      if (I.getOpcode() == Instruction::LShr) {
-        assert(ShiftOp->getOpcode() == Instruction::Shl);
-        Value *Shift = Builder->CreateLShr(X, ConstantInt::get(Ty, ShiftDiff));
-        
-        APInt Mask(APInt::getLowBitsSet(TypeBits, TypeBits - ShiftAmt2));
-        return BinaryOperator::CreateAnd(Shift,
-                                         ConstantInt::get(*Context, Mask));
-      }
-      
-      // We can't handle (X << C1) >>s C2, it shifts arbitrary bits in.
-    } else {
-      assert(ShiftAmt2 < ShiftAmt1);
-      uint32_t ShiftDiff = ShiftAmt1-ShiftAmt2;
-
-      // (X >>? C1) << C2 --> X >>? (C1-C2) & (-1 << C2)
-      if (I.getOpcode() == Instruction::Shl) {
-        assert(ShiftOp->getOpcode() == Instruction::LShr ||
-               ShiftOp->getOpcode() == Instruction::AShr);
-        Value *Shift = Builder->CreateBinOp(ShiftOp->getOpcode(), X,
-                                            ConstantInt::get(Ty, ShiftDiff));
-        
-        APInt Mask(APInt::getHighBitsSet(TypeBits, TypeBits - ShiftAmt2));
-        return BinaryOperator::CreateAnd(Shift,
-                                         ConstantInt::get(*Context, Mask));
-      }
-      
-      // (X << C1) >>u C2  --> X << (C1-C2) & (-1 >> C2)
-      if (I.getOpcode() == Instruction::LShr) {
-        assert(ShiftOp->getOpcode() == Instruction::Shl);
-        Value *Shift = Builder->CreateShl(X, ConstantInt::get(Ty, ShiftDiff));
-        
-        APInt Mask(APInt::getLowBitsSet(TypeBits, TypeBits - ShiftAmt2));
-        return BinaryOperator::CreateAnd(Shift,
-                                         ConstantInt::get(*Context, Mask));
-      }
-      
-      // We can't handle (X << C1) >>a C2, it shifts arbitrary bits in.
-    }
-  }
-  return 0;
-}
-
-
-/// DecomposeSimpleLinearExpr - Analyze 'Val', seeing if it is a simple linear
-/// expression.  If so, decompose it, returning some value X, such that Val is
-/// X*Scale+Offset.
-///
-static Value *DecomposeSimpleLinearExpr(Value *Val, unsigned &Scale,
-                                        int &Offset, LLVMContext *Context) {
-  assert(Val->getType() == Type::getInt32Ty(*Context) && 
-         "Unexpected allocation size type!");
-  if (ConstantInt *CI = dyn_cast<ConstantInt>(Val)) {
-    Offset = CI->getZExtValue();
-    Scale  = 0;
-    return ConstantInt::get(Type::getInt32Ty(*Context), 0);
-  } else if (BinaryOperator *I = dyn_cast<BinaryOperator>(Val)) {
-    if (ConstantInt *RHS = dyn_cast<ConstantInt>(I->getOperand(1))) {
-      if (I->getOpcode() == Instruction::Shl) {
-        // This is a value scaled by '1 << the shift amt'.
-        Scale = 1U << RHS->getZExtValue();
-        Offset = 0;
-        return I->getOperand(0);
-      } else if (I->getOpcode() == Instruction::Mul) {
-        // This value is scaled by 'RHS'.
-        Scale = RHS->getZExtValue();
-        Offset = 0;
-        return I->getOperand(0);
-      } else if (I->getOpcode() == Instruction::Add) {
-        // We have X+C.  Check to see if we really have (X*C2)+C1, 
-        // where C1 is divisible by C2.
-        unsigned SubScale;
-        Value *SubVal = 
-          DecomposeSimpleLinearExpr(I->getOperand(0), SubScale,
-                                    Offset, Context);
-        Offset += RHS->getZExtValue();
-        Scale = SubScale;
-        return SubVal;
-      }
-    }
-  }
-
-  // Otherwise, we can't look past this.
-  Scale = 1;
-  Offset = 0;
-  return Val;
-}
-
-
-/// PromoteCastOfAllocation - If we find a cast of an allocation instruction,
-/// try to eliminate the cast by moving the type information into the alloc.
-Instruction *InstCombiner::PromoteCastOfAllocation(BitCastInst &CI,
-                                                   AllocaInst &AI) {
-  const PointerType *PTy = cast<PointerType>(CI.getType());
-  
-  BuilderTy AllocaBuilder(*Builder);
-  AllocaBuilder.SetInsertPoint(AI.getParent(), &AI);
-  
-  // Remove any uses of AI that are dead.
-  assert(!CI.use_empty() && "Dead instructions should be removed earlier!");
-  
-  for (Value::use_iterator UI = AI.use_begin(), E = AI.use_end(); UI != E; ) {
-    Instruction *User = cast<Instruction>(*UI++);
-    if (isInstructionTriviallyDead(User)) {
-      while (UI != E && *UI == User)
-        ++UI; // If this instruction uses AI more than once, don't break UI.
-      
-      ++NumDeadInst;
-      DEBUG(errs() << "IC: DCE: " << *User << '\n');
-      EraseInstFromFunction(*User);
-    }
-  }
-
-  // This requires TargetData to get the alloca alignment and size information.
-  if (!TD) return 0;
-
-  // Get the type really allocated and the type casted to.
-  const Type *AllocElTy = AI.getAllocatedType();
-  const Type *CastElTy = PTy->getElementType();
-  if (!AllocElTy->isSized() || !CastElTy->isSized()) return 0;
-
-  unsigned AllocElTyAlign = TD->getABITypeAlignment(AllocElTy);
-  unsigned CastElTyAlign = TD->getABITypeAlignment(CastElTy);
-  if (CastElTyAlign < AllocElTyAlign) return 0;
-
-  // If the allocation has multiple uses, only promote it if we are strictly
-  // increasing the alignment of the resultant allocation.  If we keep it the
-  // same, we open the door to infinite loops of various kinds.  (A reference
-  // from a dbg.declare doesn't count as a use for this purpose.)
-  if (!AI.hasOneUse() && !hasOneUsePlusDeclare(&AI) &&
-      CastElTyAlign == AllocElTyAlign) return 0;
-
-  uint64_t AllocElTySize = TD->getTypeAllocSize(AllocElTy);
-  uint64_t CastElTySize = TD->getTypeAllocSize(CastElTy);
-  if (CastElTySize == 0 || AllocElTySize == 0) return 0;
-
-  // See if we can satisfy the modulus by pulling a scale out of the array
-  // size argument.
-  unsigned ArraySizeScale;
-  int ArrayOffset;
-  Value *NumElements = // See if the array size is a decomposable linear expr.
-    DecomposeSimpleLinearExpr(AI.getOperand(0), ArraySizeScale,
-                              ArrayOffset, Context);
- 
-  // If we can now satisfy the modulus, by using a non-1 scale, we really can
-  // do the xform.
-  if ((AllocElTySize*ArraySizeScale) % CastElTySize != 0 ||
-      (AllocElTySize*ArrayOffset   ) % CastElTySize != 0) return 0;
-
-  unsigned Scale = (AllocElTySize*ArraySizeScale)/CastElTySize;
-  Value *Amt = 0;
-  if (Scale == 1) {
-    Amt = NumElements;
-  } else {
-    Amt = ConstantInt::get(Type::getInt32Ty(*Context), Scale);
-    // Insert before the alloca, not before the cast.
-    Amt = AllocaBuilder.CreateMul(Amt, NumElements, "tmp");
-  }
-  
-  if (int Offset = (AllocElTySize*ArrayOffset)/CastElTySize) {
-    Value *Off = ConstantInt::get(Type::getInt32Ty(*Context), Offset, true);
-    Amt = AllocaBuilder.CreateAdd(Amt, Off, "tmp");
-  }
-  
-  AllocaInst *New = AllocaBuilder.CreateAlloca(CastElTy, Amt);
-  New->setAlignment(AI.getAlignment());
-  New->takeName(&AI);
-  
-  // If the allocation has one real use plus a dbg.declare, just remove the
-  // declare.
-  if (DbgDeclareInst *DI = hasOneUsePlusDeclare(&AI)) {
-    EraseInstFromFunction(*DI);
-  }
-  // If the allocation has multiple real uses, insert a cast and change all
-  // things that used it to use the new cast.  This will also hack on CI, but it
-  // will die soon.
-  else if (!AI.hasOneUse()) {
-    // New is the allocation instruction, pointer typed. AI is the original
-    // allocation instruction, also pointer typed. Thus, cast to use is BitCast.
-    Value *NewCast = AllocaBuilder.CreateBitCast(New, AI.getType(), "tmpcast");
-    AI.replaceAllUsesWith(NewCast);
-  }
-  return ReplaceInstUsesWith(CI, New);
-}
-
-/// CanEvaluateInDifferentType - Return true if we can take the specified value
-/// and return it as type Ty without inserting any new casts and without
-/// changing the computed value.  This is used by code that tries to decide
-/// whether promoting or shrinking integer operations to wider or smaller types
-/// will allow us to eliminate a truncate or extend.
-///
-/// This is a truncation operation if Ty is smaller than V->getType(), or an
-/// extension operation if Ty is larger.
-///
-/// If CastOpc is a truncation, then Ty will be a type smaller than V.  We
-/// should return true if trunc(V) can be computed by computing V in the smaller
-/// type.  If V is an instruction, then trunc(inst(x,y)) can be computed as
-/// inst(trunc(x),trunc(y)), which only makes sense if x and y can be
-/// efficiently truncated.
-///
-/// If CastOpc is a sext or zext, we are asking if the low bits of the value can
-/// bit computed in a larger type, which is then and'd or sext_in_reg'd to get
-/// the final result.
-bool InstCombiner::CanEvaluateInDifferentType(Value *V, const Type *Ty,
-                                              unsigned CastOpc,
-                                              int &NumCastsRemoved){
-  // We can always evaluate constants in another type.
-  if (isa<Constant>(V))
-    return true;
-  
-  Instruction *I = dyn_cast<Instruction>(V);
-  if (!I) return false;
-  
-  const Type *OrigTy = V->getType();
-  
-  // If this is an extension or truncate, we can often eliminate it.
-  if (isa<TruncInst>(I) || isa<ZExtInst>(I) || isa<SExtInst>(I)) {
-    // If this is a cast from the destination type, we can trivially eliminate
-    // it, and this will remove a cast overall.
-    if (I->getOperand(0)->getType() == Ty) {
-      // If the first operand is itself a cast, and is eliminable, do not count
-      // this as an eliminable cast.  We would prefer to eliminate those two
-      // casts first.
-      if (!isa<CastInst>(I->getOperand(0)) && I->hasOneUse())
-        ++NumCastsRemoved;
-      return true;
-    }
-  }
-
-  // We can't extend or shrink something that has multiple uses: doing so would
-  // require duplicating the instruction in general, which isn't profitable.
-  if (!I->hasOneUse()) return false;
-
-  unsigned Opc = I->getOpcode();
-  switch (Opc) {
-  case Instruction::Add:
-  case Instruction::Sub:
-  case Instruction::Mul:
-  case Instruction::And:
-  case Instruction::Or:
-  case Instruction::Xor:
-    // These operators can all arbitrarily be extended or truncated.
-    return CanEvaluateInDifferentType(I->getOperand(0), Ty, CastOpc,
-                                      NumCastsRemoved) &&
-           CanEvaluateInDifferentType(I->getOperand(1), Ty, CastOpc,
-                                      NumCastsRemoved);
-
-  case Instruction::UDiv:
-  case Instruction::URem: {
-    // UDiv and URem can be truncated if all the truncated bits are zero.
-    uint32_t OrigBitWidth = OrigTy->getScalarSizeInBits();
-    uint32_t BitWidth = Ty->getScalarSizeInBits();
-    if (BitWidth < OrigBitWidth) {
-      APInt Mask = APInt::getHighBitsSet(OrigBitWidth, OrigBitWidth-BitWidth);
-      if (MaskedValueIsZero(I->getOperand(0), Mask) &&
-          MaskedValueIsZero(I->getOperand(1), Mask)) {
-        return CanEvaluateInDifferentType(I->getOperand(0), Ty, CastOpc,
-                                          NumCastsRemoved) &&
-               CanEvaluateInDifferentType(I->getOperand(1), Ty, CastOpc,
-                                          NumCastsRemoved);
-      }
-    }
-    break;
-  }
-  case Instruction::Shl:
-    // If we are truncating the result of this SHL, and if it's a shift of a
-    // constant amount, we can always perform a SHL in a smaller type.
-    if (ConstantInt *CI = dyn_cast<ConstantInt>(I->getOperand(1))) {
-      uint32_t BitWidth = Ty->getScalarSizeInBits();
-      if (BitWidth < OrigTy->getScalarSizeInBits() &&
-          CI->getLimitedValue(BitWidth) < BitWidth)
-        return CanEvaluateInDifferentType(I->getOperand(0), Ty, CastOpc,
-                                          NumCastsRemoved);
-    }
-    break;
-  case Instruction::LShr:
-    // If this is a truncate of a logical shr, we can truncate it to a smaller
-    // lshr iff we know that the bits we would otherwise be shifting in are
-    // already zeros.
-    if (ConstantInt *CI = dyn_cast<ConstantInt>(I->getOperand(1))) {
-      uint32_t OrigBitWidth = OrigTy->getScalarSizeInBits();
-      uint32_t BitWidth = Ty->getScalarSizeInBits();
-      if (BitWidth < OrigBitWidth &&
-          MaskedValueIsZero(I->getOperand(0),
-            APInt::getHighBitsSet(OrigBitWidth, OrigBitWidth-BitWidth)) &&
-          CI->getLimitedValue(BitWidth) < BitWidth) {
-        return CanEvaluateInDifferentType(I->getOperand(0), Ty, CastOpc,
-                                          NumCastsRemoved);
-      }
-    }
-    break;
-  case Instruction::ZExt:
-  case Instruction::SExt:
-  case Instruction::Trunc:
-    // If this is the same kind of case as our original (e.g. zext+zext), we
-    // can safely replace it.  Note that replacing it does not reduce the number
-    // of casts in the input.
-    if (Opc == CastOpc)
-      return true;
-
-    // sext (zext ty1), ty2 -> zext ty2
-    if (CastOpc == Instruction::SExt && Opc == Instruction::ZExt)
-      return true;
-    break;
-  case Instruction::Select: {
-    SelectInst *SI = cast<SelectInst>(I);
-    return CanEvaluateInDifferentType(SI->getTrueValue(), Ty, CastOpc,
-                                      NumCastsRemoved) &&
-           CanEvaluateInDifferentType(SI->getFalseValue(), Ty, CastOpc,
-                                      NumCastsRemoved);
-  }
-  case Instruction::PHI: {
-    // We can change a phi if we can change all operands.
-    PHINode *PN = cast<PHINode>(I);
-    for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
-      if (!CanEvaluateInDifferentType(PN->getIncomingValue(i), Ty, CastOpc,
-                                      NumCastsRemoved))
-        return false;
-    return true;
-  }
-  default:
-    // TODO: Can handle more cases here.
-    break;
-  }
-  
-  return false;
-}
-
-/// EvaluateInDifferentType - Given an expression that 
-/// CanEvaluateInDifferentType returns true for, actually insert the code to
-/// evaluate the expression.
-Value *InstCombiner::EvaluateInDifferentType(Value *V, const Type *Ty, 
-                                             bool isSigned) {
-  if (Constant *C = dyn_cast<Constant>(V))
-    return ConstantExpr::getIntegerCast(C, Ty, isSigned /*Sext or ZExt*/);
-
-  // Otherwise, it must be an instruction.
-  Instruction *I = cast<Instruction>(V);
-  Instruction *Res = 0;
-  unsigned Opc = I->getOpcode();
-  switch (Opc) {
-  case Instruction::Add:
-  case Instruction::Sub:
-  case Instruction::Mul:
-  case Instruction::And:
-  case Instruction::Or:
-  case Instruction::Xor:
-  case Instruction::AShr:
-  case Instruction::LShr:
-  case Instruction::Shl:
-  case Instruction::UDiv:
-  case Instruction::URem: {
-    Value *LHS = EvaluateInDifferentType(I->getOperand(0), Ty, isSigned);
-    Value *RHS = EvaluateInDifferentType(I->getOperand(1), Ty, isSigned);
-    Res = BinaryOperator::Create((Instruction::BinaryOps)Opc, LHS, RHS);
-    break;
-  }    
-  case Instruction::Trunc:
-  case Instruction::ZExt:
-  case Instruction::SExt:
-    // If the source type of the cast is the type we're trying for then we can
-    // just return the source.  There's no need to insert it because it is not
-    // new.
-    if (I->getOperand(0)->getType() == Ty)
-      return I->getOperand(0);
-    
-    // Otherwise, must be the same type of cast, so just reinsert a new one.
-    Res = CastInst::Create(cast<CastInst>(I)->getOpcode(), I->getOperand(0),Ty);
-    break;
-  case Instruction::Select: {
-    Value *True = EvaluateInDifferentType(I->getOperand(1), Ty, isSigned);
-    Value *False = EvaluateInDifferentType(I->getOperand(2), Ty, isSigned);
-    Res = SelectInst::Create(I->getOperand(0), True, False);
-    break;
-  }
-  case Instruction::PHI: {
-    PHINode *OPN = cast<PHINode>(I);
-    PHINode *NPN = PHINode::Create(Ty);
-    for (unsigned i = 0, e = OPN->getNumIncomingValues(); i != e; ++i) {
-      Value *V =EvaluateInDifferentType(OPN->getIncomingValue(i), Ty, isSigned);
-      NPN->addIncoming(V, OPN->getIncomingBlock(i));
-    }
-    Res = NPN;
-    break;
-  }
-  default: 
-    // TODO: Can handle more cases here.
-    llvm_unreachable("Unreachable!");
-    break;
-  }
-  
-  Res->takeName(I);
-  return InsertNewInstBefore(Res, *I);
-}
-
-/// @brief Implement the transforms common to all CastInst visitors.
-Instruction *InstCombiner::commonCastTransforms(CastInst &CI) {
-  Value *Src = CI.getOperand(0);
-
-  // Many cases of "cast of a cast" are eliminable. If it's eliminable we just
-  // eliminate it now.
-  if (CastInst *CSrc = dyn_cast<CastInst>(Src)) {   // A->B->C cast
-    if (Instruction::CastOps opc = 
-        isEliminableCastPair(CSrc, CI.getOpcode(), CI.getType(), TD)) {
-      // The first cast (CSrc) is eliminable so we need to fix up or replace
-      // the second cast (CI). CSrc will then have a good chance of being dead.
-      return CastInst::Create(opc, CSrc->getOperand(0), CI.getType());
-    }
-  }
-
-  // If we are casting a select then fold the cast into the select
-  if (SelectInst *SI = dyn_cast<SelectInst>(Src))
-    if (Instruction *NV = FoldOpIntoSelect(CI, SI, this))
-      return NV;
-
-  // If we are casting a PHI then fold the cast into the PHI
-  if (isa<PHINode>(Src)) {
-    // We don't do this if this would create a PHI node with an illegal type if
-    // it is currently legal.
-    if (!isa<IntegerType>(Src->getType()) ||
-        !isa<IntegerType>(CI.getType()) ||
-        ShouldChangeType(CI.getType(), Src->getType(), TD))
-      if (Instruction *NV = FoldOpIntoPhi(CI))
-        return NV;
-  }
-  
-  return 0;
-}
-
-/// FindElementAtOffset - Given a type and a constant offset, determine whether
-/// or not there is a sequence of GEP indices into the type that will land us at
-/// the specified offset.  If so, fill them into NewIndices and return the
-/// resultant element type, otherwise return null.
-static const Type *FindElementAtOffset(const Type *Ty, int64_t Offset, 
-                                       SmallVectorImpl<Value*> &NewIndices,
-                                       const TargetData *TD,
-                                       LLVMContext *Context) {
-  if (!TD) return 0;
-  if (!Ty->isSized()) return 0;
-  
-  // Start with the index over the outer type.  Note that the type size
-  // might be zero (even if the offset isn't zero) if the indexed type
-  // is something like [0 x {int, int}]
-  const Type *IntPtrTy = TD->getIntPtrType(*Context);
-  int64_t FirstIdx = 0;
-  if (int64_t TySize = TD->getTypeAllocSize(Ty)) {
-    FirstIdx = Offset/TySize;
-    Offset -= FirstIdx*TySize;
-    
-    // Handle hosts where % returns negative instead of values [0..TySize).
-    if (Offset < 0) {
-      --FirstIdx;
-      Offset += TySize;
-      assert(Offset >= 0);
-    }
-    assert((uint64_t)Offset < (uint64_t)TySize && "Out of range offset");
-  }
-  
-  NewIndices.push_back(ConstantInt::get(IntPtrTy, FirstIdx));
-    
-  // Index into the types.  If we fail, set OrigBase to null.
-  while (Offset) {
-    // Indexing into tail padding between struct/array elements.
-    if (uint64_t(Offset*8) >= TD->getTypeSizeInBits(Ty))
-      return 0;
-    
-    if (const StructType *STy = dyn_cast<StructType>(Ty)) {
-      const StructLayout *SL = TD->getStructLayout(STy);
-      assert(Offset < (int64_t)SL->getSizeInBytes() &&
-             "Offset must stay within the indexed type");
-      
-      unsigned Elt = SL->getElementContainingOffset(Offset);
-      NewIndices.push_back(ConstantInt::get(Type::getInt32Ty(*Context), Elt));
-      
-      Offset -= SL->getElementOffset(Elt);
-      Ty = STy->getElementType(Elt);
-    } else if (const ArrayType *AT = dyn_cast<ArrayType>(Ty)) {
-      uint64_t EltSize = TD->getTypeAllocSize(AT->getElementType());
-      assert(EltSize && "Cannot index into a zero-sized array");
-      NewIndices.push_back(ConstantInt::get(IntPtrTy,Offset/EltSize));
-      Offset %= EltSize;
-      Ty = AT->getElementType();
-    } else {
-      // Otherwise, we can't index into the middle of this atomic type, bail.
-      return 0;
-    }
-  }
-  
-  return Ty;
-}
-
-/// @brief Implement the transforms for cast of pointer (bitcast/ptrtoint)
-Instruction *InstCombiner::commonPointerCastTransforms(CastInst &CI) {
-  Value *Src = CI.getOperand(0);
-  
-  if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Src)) {
-    // If casting the result of a getelementptr instruction with no offset, turn
-    // this into a cast of the original pointer!
-    if (GEP->hasAllZeroIndices()) {
-      // Changing the cast operand is usually not a good idea but it is safe
-      // here because the pointer operand is being replaced with another 
-      // pointer operand so the opcode doesn't need to change.
-      Worklist.Add(GEP);
-      CI.setOperand(0, GEP->getOperand(0));
-      return &CI;
-    }
-    
-    // If the GEP has a single use, and the base pointer is a bitcast, and the
-    // GEP computes a constant offset, see if we can convert these three
-    // instructions into fewer.  This typically happens with unions and other
-    // non-type-safe code.
-    if (TD && GEP->hasOneUse() && isa<BitCastInst>(GEP->getOperand(0))) {
-      if (GEP->hasAllConstantIndices()) {
-        // We are guaranteed to get a constant from EmitGEPOffset.
-        ConstantInt *OffsetV = cast<ConstantInt>(EmitGEPOffset(GEP, *this));
-        int64_t Offset = OffsetV->getSExtValue();
-        
-        // Get the base pointer input of the bitcast, and the type it points to.
-        Value *OrigBase = cast<BitCastInst>(GEP->getOperand(0))->getOperand(0);
-        const Type *GEPIdxTy =
-          cast<PointerType>(OrigBase->getType())->getElementType();
-        SmallVector<Value*, 8> NewIndices;
-        if (FindElementAtOffset(GEPIdxTy, Offset, NewIndices, TD, Context)) {
-          // If we were able to index down into an element, create the GEP
-          // and bitcast the result.  This eliminates one bitcast, potentially
-          // two.
-          Value *NGEP = cast<GEPOperator>(GEP)->isInBounds() ?
-            Builder->CreateInBoundsGEP(OrigBase,
-                                       NewIndices.begin(), NewIndices.end()) :
-            Builder->CreateGEP(OrigBase, NewIndices.begin(), NewIndices.end());
-          NGEP->takeName(GEP);
-          
-          if (isa<BitCastInst>(CI))
-            return new BitCastInst(NGEP, CI.getType());
-          assert(isa<PtrToIntInst>(CI));
-          return new PtrToIntInst(NGEP, CI.getType());
-        }
-      }      
-    }
-  }
-    
-  return commonCastTransforms(CI);
-}
-
-/// commonIntCastTransforms - This function implements the common transforms
-/// for trunc, zext, and sext.
-Instruction *InstCombiner::commonIntCastTransforms(CastInst &CI) {
-  if (Instruction *Result = commonCastTransforms(CI))
-    return Result;
-
-  Value *Src = CI.getOperand(0);
-  const Type *SrcTy = Src->getType();
-  const Type *DestTy = CI.getType();
-  uint32_t SrcBitSize = SrcTy->getScalarSizeInBits();
-  uint32_t DestBitSize = DestTy->getScalarSizeInBits();
-
-  // See if we can simplify any instructions used by the LHS whose sole 
-  // purpose is to compute bits we don't care about.
-  if (SimplifyDemandedInstructionBits(CI))
-    return &CI;
-
-  // If the source isn't an instruction or has more than one use then we
-  // can't do anything more. 
-  Instruction *SrcI = dyn_cast<Instruction>(Src);
-  if (!SrcI || !Src->hasOneUse())
-    return 0;
-
-  // Attempt to propagate the cast into the instruction for int->int casts.
-  int NumCastsRemoved = 0;
-  // Only do this if the dest type is a simple type, don't convert the
-  // expression tree to something weird like i93 unless the source is also
-  // strange.
-  if ((isa<VectorType>(DestTy) ||
-       ShouldChangeType(SrcI->getType(), DestTy, TD)) &&
-      CanEvaluateInDifferentType(SrcI, DestTy,
-                                 CI.getOpcode(), NumCastsRemoved)) {
-    // If this cast is a truncate, evaluting in a different type always
-    // eliminates the cast, so it is always a win.  If this is a zero-extension,
-    // we need to do an AND to maintain the clear top-part of the computation,
-    // so we require that the input have eliminated at least one cast.  If this
-    // is a sign extension, we insert two new casts (to do the extension) so we
-    // require that two casts have been eliminated.
-    bool DoXForm = false;
-    bool JustReplace = false;
-    switch (CI.getOpcode()) {
-    default:
-      // All the others use floating point so we shouldn't actually 
-      // get here because of the check above.
-      llvm_unreachable("Unknown cast type");
-    case Instruction::Trunc:
-      DoXForm = true;
-      break;
-    case Instruction::ZExt: {
-      DoXForm = NumCastsRemoved >= 1;
-      
-      if (!DoXForm && 0) {
-        // If it's unnecessary to issue an AND to clear the high bits, it's
-        // always profitable to do this xform.
-        Value *TryRes = EvaluateInDifferentType(SrcI, DestTy, false);
-        APInt Mask(APInt::getBitsSet(DestBitSize, SrcBitSize, DestBitSize));
-        if (MaskedValueIsZero(TryRes, Mask))
-          return ReplaceInstUsesWith(CI, TryRes);
-        
-        if (Instruction *TryI = dyn_cast<Instruction>(TryRes))
-          if (TryI->use_empty())
-            EraseInstFromFunction(*TryI);
-      }
-      break;
-    }
-    case Instruction::SExt: {
-      DoXForm = NumCastsRemoved >= 2;
-      if (!DoXForm && !isa<TruncInst>(SrcI) && 0) {
-        // If we do not have to emit the truncate + sext pair, then it's always
-        // profitable to do this xform.
-        //
-        // It's not safe to eliminate the trunc + sext pair if one of the
-        // eliminated cast is a truncate. e.g.
-        // t2 = trunc i32 t1 to i16
-        // t3 = sext i16 t2 to i32
-        // !=
-        // i32 t1
-        Value *TryRes = EvaluateInDifferentType(SrcI, DestTy, true);
-        unsigned NumSignBits = ComputeNumSignBits(TryRes);
-        if (NumSignBits > (DestBitSize - SrcBitSize))
-          return ReplaceInstUsesWith(CI, TryRes);
-        
-        if (Instruction *TryI = dyn_cast<Instruction>(TryRes))
-          if (TryI->use_empty())
-            EraseInstFromFunction(*TryI);
-      }
-      break;
-    }
-    }
-    
-    if (DoXForm) {
-      DEBUG(errs() << "ICE: EvaluateInDifferentType converting expression type"
-            " to avoid cast: " << CI);
-      Value *Res = EvaluateInDifferentType(SrcI, DestTy, 
-                                           CI.getOpcode() == Instruction::SExt);
-      if (JustReplace)
-        // Just replace this cast with the result.
-        return ReplaceInstUsesWith(CI, Res);
-
-      assert(Res->getType() == DestTy);
-      switch (CI.getOpcode()) {
-      default: llvm_unreachable("Unknown cast type!");
-      case Instruction::Trunc:
-        // Just replace this cast with the result.
-        return ReplaceInstUsesWith(CI, Res);
-      case Instruction::ZExt: {
-        assert(SrcBitSize < DestBitSize && "Not a zext?");
-
-        // If the high bits are already zero, just replace this cast with the
-        // result.
-        APInt Mask(APInt::getBitsSet(DestBitSize, SrcBitSize, DestBitSize));
-        if (MaskedValueIsZero(Res, Mask))
-          return ReplaceInstUsesWith(CI, Res);
-
-        // We need to emit an AND to clear the high bits.
-        Constant *C = ConstantInt::get(*Context, 
-                                 APInt::getLowBitsSet(DestBitSize, SrcBitSize));
-        return BinaryOperator::CreateAnd(Res, C);
-      }
-      case Instruction::SExt: {
-        // If the high bits are already filled with sign bit, just replace this
-        // cast with the result.
-        unsigned NumSignBits = ComputeNumSignBits(Res);
-        if (NumSignBits > (DestBitSize - SrcBitSize))
-          return ReplaceInstUsesWith(CI, Res);
-
-        // We need to emit a cast to truncate, then a cast to sext.
-        return new SExtInst(Builder->CreateTrunc(Res, Src->getType()), DestTy);
-      }
-      }
-    }
-  }
-  
-  Value *Op0 = SrcI->getNumOperands() > 0 ? SrcI->getOperand(0) : 0;
-  Value *Op1 = SrcI->getNumOperands() > 1 ? SrcI->getOperand(1) : 0;
-
-  switch (SrcI->getOpcode()) {
-  case Instruction::Add:
-  case Instruction::Mul:
-  case Instruction::And:
-  case Instruction::Or:
-  case Instruction::Xor:
-    // If we are discarding information, rewrite.
-    if (DestBitSize < SrcBitSize && DestBitSize != 1) {
-      // Don't insert two casts unless at least one can be eliminated.
-      if (!ValueRequiresCast(CI.getOpcode(), Op1, DestTy, TD) ||
-          !ValueRequiresCast(CI.getOpcode(), Op0, DestTy, TD)) {
-        Value *Op0c = Builder->CreateTrunc(Op0, DestTy, Op0->getName());
-        Value *Op1c = Builder->CreateTrunc(Op1, DestTy, Op1->getName());
-        return BinaryOperator::Create(
-            cast<BinaryOperator>(SrcI)->getOpcode(), Op0c, Op1c);
-      }
-    }
-
-    // cast (xor bool X, true) to int  --> xor (cast bool X to int), 1
-    if (isa<ZExtInst>(CI) && SrcBitSize == 1 && 
-        SrcI->getOpcode() == Instruction::Xor &&
-        Op1 == ConstantInt::getTrue(*Context) &&
-        (!Op0->hasOneUse() || !isa<CmpInst>(Op0))) {
-      Value *New = Builder->CreateZExt(Op0, DestTy, Op0->getName());
-      return BinaryOperator::CreateXor(New,
-                                      ConstantInt::get(CI.getType(), 1));
-    }
-    break;
-
-  case Instruction::Shl: {
-    // Canonicalize trunc inside shl, if we can.
-    ConstantInt *CI = dyn_cast<ConstantInt>(Op1);
-    if (CI && DestBitSize < SrcBitSize &&
-        CI->getLimitedValue(DestBitSize) < DestBitSize) {
-      Value *Op0c = Builder->CreateTrunc(Op0, DestTy, Op0->getName());
-      Value *Op1c = Builder->CreateTrunc(Op1, DestTy, Op1->getName());
-      return BinaryOperator::CreateShl(Op0c, Op1c);
-    }
-    break;
-  }
-  }
-  return 0;
-}
-
-Instruction *InstCombiner::visitTrunc(TruncInst &CI) {
-  if (Instruction *Result = commonIntCastTransforms(CI))
-    return Result;
-  
-  Value *Src = CI.getOperand(0);
-  const Type *Ty = CI.getType();
-  uint32_t DestBitWidth = Ty->getScalarSizeInBits();
-  uint32_t SrcBitWidth = Src->getType()->getScalarSizeInBits();
-
-  // Canonicalize trunc x to i1 -> (icmp ne (and x, 1), 0)
-  if (DestBitWidth == 1) {
-    Constant *One = ConstantInt::get(Src->getType(), 1);
-    Src = Builder->CreateAnd(Src, One, "tmp");
-    Value *Zero = Constant::getNullValue(Src->getType());
-    return new ICmpInst(ICmpInst::ICMP_NE, Src, Zero);
-  }
-
-  // Optimize trunc(lshr(), c) to pull the shift through the truncate.
-  ConstantInt *ShAmtV = 0;
-  Value *ShiftOp = 0;
-  if (Src->hasOneUse() &&
-      match(Src, m_LShr(m_Value(ShiftOp), m_ConstantInt(ShAmtV)))) {
-    uint32_t ShAmt = ShAmtV->getLimitedValue(SrcBitWidth);
-    
-    // Get a mask for the bits shifting in.
-    APInt Mask(APInt::getLowBitsSet(SrcBitWidth, ShAmt).shl(DestBitWidth));
-    if (MaskedValueIsZero(ShiftOp, Mask)) {
-      if (ShAmt >= DestBitWidth)        // All zeros.
-        return ReplaceInstUsesWith(CI, Constant::getNullValue(Ty));
-      
-      // Okay, we can shrink this.  Truncate the input, then return a new
-      // shift.
-      Value *V1 = Builder->CreateTrunc(ShiftOp, Ty, ShiftOp->getName());
-      Value *V2 = ConstantExpr::getTrunc(ShAmtV, Ty);
-      return BinaryOperator::CreateLShr(V1, V2);
-    }
-  }
- 
-  return 0;
-}
-
-/// transformZExtICmp - Transform (zext icmp) to bitwise / integer operations
-/// in order to eliminate the icmp.
-Instruction *InstCombiner::transformZExtICmp(ICmpInst *ICI, Instruction &CI,
-                                             bool DoXform) {
-  // If we are just checking for a icmp eq of a single bit and zext'ing it
-  // to an integer, then shift the bit to the appropriate place and then
-  // cast to integer to avoid the comparison.
-  if (ConstantInt *Op1C = dyn_cast<ConstantInt>(ICI->getOperand(1))) {
-    const APInt &Op1CV = Op1C->getValue();
-      
-    // zext (x <s  0) to i32 --> x>>u31      true if signbit set.
-    // zext (x >s -1) to i32 --> (x>>u31)^1  true if signbit clear.
-    if ((ICI->getPredicate() == ICmpInst::ICMP_SLT && Op1CV == 0) ||
-        (ICI->getPredicate() == ICmpInst::ICMP_SGT &&Op1CV.isAllOnesValue())) {
-      if (!DoXform) return ICI;
-
-      Value *In = ICI->getOperand(0);
-      Value *Sh = ConstantInt::get(In->getType(),
-                                   In->getType()->getScalarSizeInBits()-1);
-      In = Builder->CreateLShr(In, Sh, In->getName()+".lobit");
-      if (In->getType() != CI.getType())
-        In = Builder->CreateIntCast(In, CI.getType(), false/*ZExt*/, "tmp");
-
-      if (ICI->getPredicate() == ICmpInst::ICMP_SGT) {
-        Constant *One = ConstantInt::get(In->getType(), 1);
-        In = Builder->CreateXor(In, One, In->getName()+".not");
-      }
-
-      return ReplaceInstUsesWith(CI, In);
-    }
-      
-      
-      
-    // zext (X == 0) to i32 --> X^1      iff X has only the low bit set.
-    // zext (X == 0) to i32 --> (X>>1)^1 iff X has only the 2nd bit set.
-    // zext (X == 1) to i32 --> X        iff X has only the low bit set.
-    // zext (X == 2) to i32 --> X>>1     iff X has only the 2nd bit set.
-    // zext (X != 0) to i32 --> X        iff X has only the low bit set.
-    // zext (X != 0) to i32 --> X>>1     iff X has only the 2nd bit set.
-    // zext (X != 1) to i32 --> X^1      iff X has only the low bit set.
-    // zext (X != 2) to i32 --> (X>>1)^1 iff X has only the 2nd bit set.
-    if ((Op1CV == 0 || Op1CV.isPowerOf2()) && 
-        // This only works for EQ and NE
-        ICI->isEquality()) {
-      // If Op1C some other power of two, convert:
-      uint32_t BitWidth = Op1C->getType()->getBitWidth();
-      APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
-      APInt TypeMask(APInt::getAllOnesValue(BitWidth));
-      ComputeMaskedBits(ICI->getOperand(0), TypeMask, KnownZero, KnownOne);
-        
-      APInt KnownZeroMask(~KnownZero);
-      if (KnownZeroMask.isPowerOf2()) { // Exactly 1 possible 1?
-        if (!DoXform) return ICI;
-
-        bool isNE = ICI->getPredicate() == ICmpInst::ICMP_NE;
-        if (Op1CV != 0 && (Op1CV != KnownZeroMask)) {
-          // (X&4) == 2 --> false
-          // (X&4) != 2 --> true
-          Constant *Res = ConstantInt::get(Type::getInt1Ty(*Context), isNE);
-          Res = ConstantExpr::getZExt(Res, CI.getType());
-          return ReplaceInstUsesWith(CI, Res);
-        }
-          
-        uint32_t ShiftAmt = KnownZeroMask.logBase2();
-        Value *In = ICI->getOperand(0);
-        if (ShiftAmt) {
-          // Perform a logical shr by shiftamt.
-          // Insert the shift to put the result in the low bit.
-          In = Builder->CreateLShr(In, ConstantInt::get(In->getType(),ShiftAmt),
-                                   In->getName()+".lobit");
-        }
-          
-        if ((Op1CV != 0) == isNE) { // Toggle the low bit.
-          Constant *One = ConstantInt::get(In->getType(), 1);
-          In = Builder->CreateXor(In, One, "tmp");
-        }
-          
-        if (CI.getType() == In->getType())
-          return ReplaceInstUsesWith(CI, In);
-        else
-          return CastInst::CreateIntegerCast(In, CI.getType(), false/*ZExt*/);
-      }
-    }
-  }
-
-  // icmp ne A, B is equal to xor A, B when A and B only really have one bit.
-  // It is also profitable to transform icmp eq into not(xor(A, B)) because that
-  // may lead to additional simplifications.
-  if (ICI->isEquality() && CI.getType() == ICI->getOperand(0)->getType()) {
-    if (const IntegerType *ITy = dyn_cast<IntegerType>(CI.getType())) {
-      uint32_t BitWidth = ITy->getBitWidth();
-      Value *LHS = ICI->getOperand(0);
-      Value *RHS = ICI->getOperand(1);
-
-      APInt KnownZeroLHS(BitWidth, 0), KnownOneLHS(BitWidth, 0);
-      APInt KnownZeroRHS(BitWidth, 0), KnownOneRHS(BitWidth, 0);
-      APInt TypeMask(APInt::getAllOnesValue(BitWidth));
-      ComputeMaskedBits(LHS, TypeMask, KnownZeroLHS, KnownOneLHS);
-      ComputeMaskedBits(RHS, TypeMask, KnownZeroRHS, KnownOneRHS);
-
-      if (KnownZeroLHS == KnownZeroRHS && KnownOneLHS == KnownOneRHS) {
-        APInt KnownBits = KnownZeroLHS | KnownOneLHS;
-        APInt UnknownBit = ~KnownBits;
-        if (UnknownBit.countPopulation() == 1) {
-          if (!DoXform) return ICI;
-
-          Value *Result = Builder->CreateXor(LHS, RHS);
-
-          // Mask off any bits that are set and won't be shifted away.
-          if (KnownOneLHS.uge(UnknownBit))
-            Result = Builder->CreateAnd(Result,
-                                        ConstantInt::get(ITy, UnknownBit));
-
-          // Shift the bit we're testing down to the lsb.
-          Result = Builder->CreateLShr(
-               Result, ConstantInt::get(ITy, UnknownBit.countTrailingZeros()));
-
-          if (ICI->getPredicate() == ICmpInst::ICMP_EQ)
-            Result = Builder->CreateXor(Result, ConstantInt::get(ITy, 1));
-          Result->takeName(ICI);
-          return ReplaceInstUsesWith(CI, Result);
-        }
-      }
-    }
-  }
-
-  return 0;
-}
-
-Instruction *InstCombiner::visitZExt(ZExtInst &CI) {
-  // If one of the common conversion will work ..
-  if (Instruction *Result = commonIntCastTransforms(CI))
-    return Result;
-
-  Value *Src = CI.getOperand(0);
-
-  // If this is a TRUNC followed by a ZEXT then we are dealing with integral
-  // types and if the sizes are just right we can convert this into a logical
-  // 'and' which will be much cheaper than the pair of casts.
-  if (TruncInst *CSrc = dyn_cast<TruncInst>(Src)) {   // A->B->C cast
-    // Get the sizes of the types involved.  We know that the intermediate type
-    // will be smaller than A or C, but don't know the relation between A and C.
-    Value *A = CSrc->getOperand(0);
-    unsigned SrcSize = A->getType()->getScalarSizeInBits();
-    unsigned MidSize = CSrc->getType()->getScalarSizeInBits();
-    unsigned DstSize = CI.getType()->getScalarSizeInBits();
-    // If we're actually extending zero bits, then if
-    // SrcSize <  DstSize: zext(a & mask)
-    // SrcSize == DstSize: a & mask
-    // SrcSize  > DstSize: trunc(a) & mask
-    if (SrcSize < DstSize) {
-      APInt AndValue(APInt::getLowBitsSet(SrcSize, MidSize));
-      Constant *AndConst = ConstantInt::get(A->getType(), AndValue);
-      Value *And = Builder->CreateAnd(A, AndConst, CSrc->getName()+".mask");
-      return new ZExtInst(And, CI.getType());
-    }
-    
-    if (SrcSize == DstSize) {
-      APInt AndValue(APInt::getLowBitsSet(SrcSize, MidSize));
-      return BinaryOperator::CreateAnd(A, ConstantInt::get(A->getType(),
-                                                           AndValue));
-    }
-    if (SrcSize > DstSize) {
-      Value *Trunc = Builder->CreateTrunc(A, CI.getType(), "tmp");
-      APInt AndValue(APInt::getLowBitsSet(DstSize, MidSize));
-      return BinaryOperator::CreateAnd(Trunc, 
-                                       ConstantInt::get(Trunc->getType(),
-                                                               AndValue));
-    }
-  }
-
-  if (ICmpInst *ICI = dyn_cast<ICmpInst>(Src))
-    return transformZExtICmp(ICI, CI);
-
-  BinaryOperator *SrcI = dyn_cast<BinaryOperator>(Src);
-  if (SrcI && SrcI->getOpcode() == Instruction::Or) {
-    // zext (or icmp, icmp) --> or (zext icmp), (zext icmp) if at least one
-    // of the (zext icmp) will be transformed.
-    ICmpInst *LHS = dyn_cast<ICmpInst>(SrcI->getOperand(0));
-    ICmpInst *RHS = dyn_cast<ICmpInst>(SrcI->getOperand(1));
-    if (LHS && RHS && LHS->hasOneUse() && RHS->hasOneUse() &&
-        (transformZExtICmp(LHS, CI, false) ||
-         transformZExtICmp(RHS, CI, false))) {
-      Value *LCast = Builder->CreateZExt(LHS, CI.getType(), LHS->getName());
-      Value *RCast = Builder->CreateZExt(RHS, CI.getType(), RHS->getName());
-      return BinaryOperator::Create(Instruction::Or, LCast, RCast);
-    }
-  }
-
-  // zext(trunc(t) & C) -> (t & zext(C)).
-  if (SrcI && SrcI->getOpcode() == Instruction::And && SrcI->hasOneUse())
-    if (ConstantInt *C = dyn_cast<ConstantInt>(SrcI->getOperand(1)))
-      if (TruncInst *TI = dyn_cast<TruncInst>(SrcI->getOperand(0))) {
-        Value *TI0 = TI->getOperand(0);
-        if (TI0->getType() == CI.getType())
-          return
-            BinaryOperator::CreateAnd(TI0,
-                                ConstantExpr::getZExt(C, CI.getType()));
-      }
-
-  // zext((trunc(t) & C) ^ C) -> ((t & zext(C)) ^ zext(C)).
-  if (SrcI && SrcI->getOpcode() == Instruction::Xor && SrcI->hasOneUse())
-    if (ConstantInt *C = dyn_cast<ConstantInt>(SrcI->getOperand(1)))
-      if (BinaryOperator *And = dyn_cast<BinaryOperator>(SrcI->getOperand(0)))
-        if (And->getOpcode() == Instruction::And && And->hasOneUse() &&
-            And->getOperand(1) == C)
-          if (TruncInst *TI = dyn_cast<TruncInst>(And->getOperand(0))) {
-            Value *TI0 = TI->getOperand(0);
-            if (TI0->getType() == CI.getType()) {
-              Constant *ZC = ConstantExpr::getZExt(C, CI.getType());
-              Value *NewAnd = Builder->CreateAnd(TI0, ZC, "tmp");
-              return BinaryOperator::CreateXor(NewAnd, ZC);
-            }
-          }
-
-  return 0;
-}
-
-Instruction *InstCombiner::visitSExt(SExtInst &CI) {
-  if (Instruction *I = commonIntCastTransforms(CI))
-    return I;
-  
-  Value *Src = CI.getOperand(0);
-  
-  // Canonicalize sign-extend from i1 to a select.
-  if (Src->getType() == Type::getInt1Ty(*Context))
-    return SelectInst::Create(Src,
-                              Constant::getAllOnesValue(CI.getType()),
-                              Constant::getNullValue(CI.getType()));
-
-  // See if the value being truncated is already sign extended.  If so, just
-  // eliminate the trunc/sext pair.
-  if (Operator::getOpcode(Src) == Instruction::Trunc) {
-    Value *Op = cast<User>(Src)->getOperand(0);
-    unsigned OpBits   = Op->getType()->getScalarSizeInBits();
-    unsigned MidBits  = Src->getType()->getScalarSizeInBits();
-    unsigned DestBits = CI.getType()->getScalarSizeInBits();
-    unsigned NumSignBits = ComputeNumSignBits(Op);
-
-    if (OpBits == DestBits) {
-      // Op is i32, Mid is i8, and Dest is i32.  If Op has more than 24 sign
-      // bits, it is already ready.
-      if (NumSignBits > DestBits-MidBits)
-        return ReplaceInstUsesWith(CI, Op);
-    } else if (OpBits < DestBits) {
-      // Op is i32, Mid is i8, and Dest is i64.  If Op has more than 24 sign
-      // bits, just sext from i32.
-      if (NumSignBits > OpBits-MidBits)
-        return new SExtInst(Op, CI.getType(), "tmp");
-    } else {
-      // Op is i64, Mid is i8, and Dest is i32.  If Op has more than 56 sign
-      // bits, just truncate to i32.
-      if (NumSignBits > OpBits-MidBits)
-        return new TruncInst(Op, CI.getType(), "tmp");
-    }
-  }
-
-  // If the input is a shl/ashr pair of a same constant, then this is a sign
-  // extension from a smaller value.  If we could trust arbitrary bitwidth
-  // integers, we could turn this into a truncate to the smaller bit and then
-  // use a sext for the whole extension.  Since we don't, look deeper and check
-  // for a truncate.  If the source and dest are the same type, eliminate the
-  // trunc and extend and just do shifts.  For example, turn:
-  //   %a = trunc i32 %i to i8
-  //   %b = shl i8 %a, 6
-  //   %c = ashr i8 %b, 6
-  //   %d = sext i8 %c to i32
-  // into:
-  //   %a = shl i32 %i, 30
-  //   %d = ashr i32 %a, 30
-  Value *A = 0;
-  ConstantInt *BA = 0, *CA = 0;
-  if (match(Src, m_AShr(m_Shl(m_Value(A), m_ConstantInt(BA)),
-                        m_ConstantInt(CA))) &&
-      BA == CA && isa<TruncInst>(A)) {
-    Value *I = cast<TruncInst>(A)->getOperand(0);
-    if (I->getType() == CI.getType()) {
-      unsigned MidSize = Src->getType()->getScalarSizeInBits();
-      unsigned SrcDstSize = CI.getType()->getScalarSizeInBits();
-      unsigned ShAmt = CA->getZExtValue()+SrcDstSize-MidSize;
-      Constant *ShAmtV = ConstantInt::get(CI.getType(), ShAmt);
-      I = Builder->CreateShl(I, ShAmtV, CI.getName());
-      return BinaryOperator::CreateAShr(I, ShAmtV);
-    }
-  }
-  
-  return 0;
-}
-
-/// FitsInFPType - Return a Constant* for the specified FP constant if it fits
-/// in the specified FP type without changing its value.
-static Constant *FitsInFPType(ConstantFP *CFP, const fltSemantics &Sem,
-                              LLVMContext *Context) {
-  bool losesInfo;
-  APFloat F = CFP->getValueAPF();
-  (void)F.convert(Sem, APFloat::rmNearestTiesToEven, &losesInfo);
-  if (!losesInfo)
-    return ConstantFP::get(*Context, F);
-  return 0;
-}
-
-/// LookThroughFPExtensions - If this is an fp extension instruction, look
-/// through it until we get the source value.
-static Value *LookThroughFPExtensions(Value *V, LLVMContext *Context) {
-  if (Instruction *I = dyn_cast<Instruction>(V))
-    if (I->getOpcode() == Instruction::FPExt)
-      return LookThroughFPExtensions(I->getOperand(0), Context);
-  
-  // If this value is a constant, return the constant in the smallest FP type
-  // that can accurately represent it.  This allows us to turn
-  // (float)((double)X+2.0) into x+2.0f.
-  if (ConstantFP *CFP = dyn_cast<ConstantFP>(V)) {
-    if (CFP->getType() == Type::getPPC_FP128Ty(*Context))
-      return V;  // No constant folding of this.
-    // See if the value can be truncated to float and then reextended.
-    if (Value *V = FitsInFPType(CFP, APFloat::IEEEsingle, Context))
-      return V;
-    if (CFP->getType() == Type::getDoubleTy(*Context))
-      return V;  // Won't shrink.
-    if (Value *V = FitsInFPType(CFP, APFloat::IEEEdouble, Context))
-      return V;
-    // Don't try to shrink to various long double types.
-  }
-  
-  return V;
-}
-
-Instruction *InstCombiner::visitFPTrunc(FPTruncInst &CI) {
-  if (Instruction *I = commonCastTransforms(CI))
-    return I;
-  
-  // If we have fptrunc(fadd (fpextend x), (fpextend y)), where x and y are
-  // smaller than the destination type, we can eliminate the truncate by doing
-  // the add as the smaller type.  This applies to fadd/fsub/fmul/fdiv as well as
-  // many builtins (sqrt, etc).
-  BinaryOperator *OpI = dyn_cast<BinaryOperator>(CI.getOperand(0));
-  if (OpI && OpI->hasOneUse()) {
-    switch (OpI->getOpcode()) {
-    default: break;
-    case Instruction::FAdd:
-    case Instruction::FSub:
-    case Instruction::FMul:
-    case Instruction::FDiv:
-    case Instruction::FRem:
-      const Type *SrcTy = OpI->getType();
-      Value *LHSTrunc = LookThroughFPExtensions(OpI->getOperand(0), Context);
-      Value *RHSTrunc = LookThroughFPExtensions(OpI->getOperand(1), Context);
-      if (LHSTrunc->getType() != SrcTy && 
-          RHSTrunc->getType() != SrcTy) {
-        unsigned DstSize = CI.getType()->getScalarSizeInBits();
-        // If the source types were both smaller than the destination type of
-        // the cast, do this xform.
-        if (LHSTrunc->getType()->getScalarSizeInBits() <= DstSize &&
-            RHSTrunc->getType()->getScalarSizeInBits() <= DstSize) {
-          LHSTrunc = Builder->CreateFPExt(LHSTrunc, CI.getType());
-          RHSTrunc = Builder->CreateFPExt(RHSTrunc, CI.getType());
-          return BinaryOperator::Create(OpI->getOpcode(), LHSTrunc, RHSTrunc);
-        }
-      }
-      break;  
-    }
-  }
-  return 0;
-}
-
-Instruction *InstCombiner::visitFPExt(CastInst &CI) {
-  return commonCastTransforms(CI);
-}
-
-Instruction *InstCombiner::visitFPToUI(FPToUIInst &FI) {
-  Instruction *OpI = dyn_cast<Instruction>(FI.getOperand(0));
-  if (OpI == 0)
-    return commonCastTransforms(FI);
-
-  // fptoui(uitofp(X)) --> X
-  // fptoui(sitofp(X)) --> X
-  // This is safe if the intermediate type has enough bits in its mantissa to
-  // accurately represent all values of X.  For example, do not do this with
-  // i64->float->i64.  This is also safe for sitofp case, because any negative
-  // 'X' value would cause an undefined result for the fptoui. 
-  if ((isa<UIToFPInst>(OpI) || isa<SIToFPInst>(OpI)) &&
-      OpI->getOperand(0)->getType() == FI.getType() &&
-      (int)FI.getType()->getScalarSizeInBits() < /*extra bit for sign */
-                    OpI->getType()->getFPMantissaWidth())
-    return ReplaceInstUsesWith(FI, OpI->getOperand(0));
-
-  return commonCastTransforms(FI);
-}
-
-Instruction *InstCombiner::visitFPToSI(FPToSIInst &FI) {
-  Instruction *OpI = dyn_cast<Instruction>(FI.getOperand(0));
-  if (OpI == 0)
-    return commonCastTransforms(FI);
-  
-  // fptosi(sitofp(X)) --> X
-  // fptosi(uitofp(X)) --> X
-  // This is safe if the intermediate type has enough bits in its mantissa to
-  // accurately represent all values of X.  For example, do not do this with
-  // i64->float->i64.  This is also safe for sitofp case, because any negative
-  // 'X' value would cause an undefined result for the fptoui. 
-  if ((isa<UIToFPInst>(OpI) || isa<SIToFPInst>(OpI)) &&
-      OpI->getOperand(0)->getType() == FI.getType() &&
-      (int)FI.getType()->getScalarSizeInBits() <=
-                    OpI->getType()->getFPMantissaWidth())
-    return ReplaceInstUsesWith(FI, OpI->getOperand(0));
-  
-  return commonCastTransforms(FI);
-}
-
-Instruction *InstCombiner::visitUIToFP(CastInst &CI) {
-  return commonCastTransforms(CI);
-}
-
-Instruction *InstCombiner::visitSIToFP(CastInst &CI) {
-  return commonCastTransforms(CI);
-}
-
-Instruction *InstCombiner::visitPtrToInt(PtrToIntInst &CI) {
-  // If the destination integer type is smaller than the intptr_t type for
-  // this target, do a ptrtoint to intptr_t then do a trunc.  This allows the
-  // trunc to be exposed to other transforms.  Don't do this for extending
-  // ptrtoint's, because we don't know if the target sign or zero extends its
-  // pointers.
-  if (TD &&
-      CI.getType()->getScalarSizeInBits() < TD->getPointerSizeInBits()) {
-    Value *P = Builder->CreatePtrToInt(CI.getOperand(0),
-                                       TD->getIntPtrType(CI.getContext()),
-                                       "tmp");
-    return new TruncInst(P, CI.getType());
-  }
-  
-  return commonPointerCastTransforms(CI);
-}
-
-Instruction *InstCombiner::visitIntToPtr(IntToPtrInst &CI) {
-  // If the source integer type is larger than the intptr_t type for
-  // this target, do a trunc to the intptr_t type, then inttoptr of it.  This
-  // allows the trunc to be exposed to other transforms.  Don't do this for
-  // extending inttoptr's, because we don't know if the target sign or zero
-  // extends to pointers.
-  if (TD && CI.getOperand(0)->getType()->getScalarSizeInBits() >
-      TD->getPointerSizeInBits()) {
-    Value *P = Builder->CreateTrunc(CI.getOperand(0),
-                                    TD->getIntPtrType(CI.getContext()), "tmp");
-    return new IntToPtrInst(P, CI.getType());
-  }
-  
-  if (Instruction *I = commonCastTransforms(CI))
-    return I;
-
-  return 0;
-}
-
-Instruction *InstCombiner::visitBitCast(BitCastInst &CI) {
-  // If the operands are integer typed then apply the integer transforms,
-  // otherwise just apply the common ones.
-  Value *Src = CI.getOperand(0);
-  const Type *SrcTy = Src->getType();
-  const Type *DestTy = CI.getType();
-
-  if (isa<PointerType>(SrcTy)) {
-    if (Instruction *I = commonPointerCastTransforms(CI))
-      return I;
-  } else {
-    if (Instruction *Result = commonCastTransforms(CI))
-      return Result;
-  }
-
-
-  // Get rid of casts from one type to the same type. These are useless and can
-  // be replaced by the operand.
-  if (DestTy == Src->getType())
-    return ReplaceInstUsesWith(CI, Src);
-
-  if (const PointerType *DstPTy = dyn_cast<PointerType>(DestTy)) {
-    const PointerType *SrcPTy = cast<PointerType>(SrcTy);
-    const Type *DstElTy = DstPTy->getElementType();
-    const Type *SrcElTy = SrcPTy->getElementType();
-    
-    // If the address spaces don't match, don't eliminate the bitcast, which is
-    // required for changing types.
-    if (SrcPTy->getAddressSpace() != DstPTy->getAddressSpace())
-      return 0;
-    
-    // If we are casting a alloca to a pointer to a type of the same
-    // size, rewrite the allocation instruction to allocate the "right" type.
-    // There is no need to modify malloc calls because it is their bitcast that
-    // needs to be cleaned up.
-    if (AllocaInst *AI = dyn_cast<AllocaInst>(Src))
-      if (Instruction *V = PromoteCastOfAllocation(CI, *AI))
-        return V;
-    
-    // If the source and destination are pointers, and this cast is equivalent
-    // to a getelementptr X, 0, 0, 0...  turn it into the appropriate gep.
-    // This can enhance SROA and other transforms that want type-safe pointers.
-    Constant *ZeroUInt = Constant::getNullValue(Type::getInt32Ty(*Context));
-    unsigned NumZeros = 0;
-    while (SrcElTy != DstElTy && 
-           isa<CompositeType>(SrcElTy) && !isa<PointerType>(SrcElTy) &&
-           SrcElTy->getNumContainedTypes() /* not "{}" */) {
-      SrcElTy = cast<CompositeType>(SrcElTy)->getTypeAtIndex(ZeroUInt);
-      ++NumZeros;
-    }
-
-    // If we found a path from the src to dest, create the getelementptr now.
-    if (SrcElTy == DstElTy) {
-      SmallVector<Value*, 8> Idxs(NumZeros+1, ZeroUInt);
-      return GetElementPtrInst::CreateInBounds(Src, Idxs.begin(), Idxs.end(), "",
-                                               ((Instruction*) NULL));
-    }
-  }
-
-  if (const VectorType *DestVTy = dyn_cast<VectorType>(DestTy)) {
-    if (DestVTy->getNumElements() == 1) {
-      if (!isa<VectorType>(SrcTy)) {
-        Value *Elem = Builder->CreateBitCast(Src, DestVTy->getElementType());
-        return InsertElementInst::Create(UndefValue::get(DestTy), Elem,
-                            Constant::getNullValue(Type::getInt32Ty(*Context)));
-      }
-      // FIXME: Canonicalize bitcast(insertelement) -> insertelement(bitcast)
-    }
-  }
-
-  if (const VectorType *SrcVTy = dyn_cast<VectorType>(SrcTy)) {
-    if (SrcVTy->getNumElements() == 1) {
-      if (!isa<VectorType>(DestTy)) {
-        Value *Elem = 
-          Builder->CreateExtractElement(Src,
-                            Constant::getNullValue(Type::getInt32Ty(*Context)));
-        return CastInst::Create(Instruction::BitCast, Elem, DestTy);
-      }
-    }
-  }
-
-  if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(Src)) {
-    if (SVI->hasOneUse()) {
-      // Okay, we have (bitconvert (shuffle ..)).  Check to see if this is
-      // a bitconvert to a vector with the same # elts.
-      if (isa<VectorType>(DestTy) && 
-          cast<VectorType>(DestTy)->getNumElements() ==
-                SVI->getType()->getNumElements() &&
-          SVI->getType()->getNumElements() ==
-            cast<VectorType>(SVI->getOperand(0)->getType())->getNumElements()) {
-        CastInst *Tmp;
-        // If either of the operands is a cast from CI.getType(), then
-        // evaluating the shuffle in the casted destination's type will allow
-        // us to eliminate at least one cast.
-        if (((Tmp = dyn_cast<CastInst>(SVI->getOperand(0))) && 
-             Tmp->getOperand(0)->getType() == DestTy) ||
-            ((Tmp = dyn_cast<CastInst>(SVI->getOperand(1))) && 
-             Tmp->getOperand(0)->getType() == DestTy)) {
-          Value *LHS = Builder->CreateBitCast(SVI->getOperand(0), DestTy);
-          Value *RHS = Builder->CreateBitCast(SVI->getOperand(1), DestTy);
-          // Return a new shuffle vector.  Use the same element ID's, as we
-          // know the vector types match #elts.
-          return new ShuffleVectorInst(LHS, RHS, SVI->getOperand(2));
-        }
-      }
-    }
-  }
-  return 0;
-}
-
-/// GetSelectFoldableOperands - We want to turn code that looks like this:
-///   %C = or %A, %B
-///   %D = select %cond, %C, %A
-/// into:
-///   %C = select %cond, %B, 0
-///   %D = or %A, %C
-///
-/// Assuming that the specified instruction is an operand to the select, return
-/// a bitmask indicating which operands of this instruction are foldable if they
-/// equal the other incoming value of the select.
-///
-static unsigned GetSelectFoldableOperands(Instruction *I) {
-  switch (I->getOpcode()) {
-  case Instruction::Add:
-  case Instruction::Mul:
-  case Instruction::And:
-  case Instruction::Or:
-  case Instruction::Xor:
-    return 3;              // Can fold through either operand.
-  case Instruction::Sub:   // Can only fold on the amount subtracted.
-  case Instruction::Shl:   // Can only fold on the shift amount.
-  case Instruction::LShr:
-  case Instruction::AShr:
-    return 1;
-  default:
-    return 0;              // Cannot fold
-  }
-}
-
-/// GetSelectFoldableConstant - For the same transformation as the previous
-/// function, return the identity constant that goes into the select.
-static Constant *GetSelectFoldableConstant(Instruction *I,
-                                           LLVMContext *Context) {
-  switch (I->getOpcode()) {
-  default: llvm_unreachable("This cannot happen!");
-  case Instruction::Add:
-  case Instruction::Sub:
-  case Instruction::Or:
-  case Instruction::Xor:
-  case Instruction::Shl:
-  case Instruction::LShr:
-  case Instruction::AShr:
-    return Constant::getNullValue(I->getType());
-  case Instruction::And:
-    return Constant::getAllOnesValue(I->getType());
-  case Instruction::Mul:
-    return ConstantInt::get(I->getType(), 1);
-  }
-}
-
-/// FoldSelectOpOp - Here we have (select c, TI, FI), and we know that TI and FI
-/// have the same opcode and only one use each.  Try to simplify this.
-Instruction *InstCombiner::FoldSelectOpOp(SelectInst &SI, Instruction *TI,
-                                          Instruction *FI) {
-  if (TI->getNumOperands() == 1) {
-    // If this is a non-volatile load or a cast from the same type,
-    // merge.
-    if (TI->isCast()) {
-      if (TI->getOperand(0)->getType() != FI->getOperand(0)->getType())
-        return 0;
-    } else {
-      return 0;  // unknown unary op.
-    }
-
-    // Fold this by inserting a select from the input values.
-    SelectInst *NewSI = SelectInst::Create(SI.getCondition(), TI->getOperand(0),
-                                          FI->getOperand(0), SI.getName()+".v");
-    InsertNewInstBefore(NewSI, SI);
-    return CastInst::Create(Instruction::CastOps(TI->getOpcode()), NewSI, 
-                            TI->getType());
-  }
-
-  // Only handle binary operators here.
-  if (!isa<BinaryOperator>(TI))
-    return 0;
-
-  // Figure out if the operations have any operands in common.
-  Value *MatchOp, *OtherOpT, *OtherOpF;
-  bool MatchIsOpZero;
-  if (TI->getOperand(0) == FI->getOperand(0)) {
-    MatchOp  = TI->getOperand(0);
-    OtherOpT = TI->getOperand(1);
-    OtherOpF = FI->getOperand(1);
-    MatchIsOpZero = true;
-  } else if (TI->getOperand(1) == FI->getOperand(1)) {
-    MatchOp  = TI->getOperand(1);
-    OtherOpT = TI->getOperand(0);
-    OtherOpF = FI->getOperand(0);
-    MatchIsOpZero = false;
-  } else if (!TI->isCommutative()) {
-    return 0;
-  } else if (TI->getOperand(0) == FI->getOperand(1)) {
-    MatchOp  = TI->getOperand(0);
-    OtherOpT = TI->getOperand(1);
-    OtherOpF = FI->getOperand(0);
-    MatchIsOpZero = true;
-  } else if (TI->getOperand(1) == FI->getOperand(0)) {
-    MatchOp  = TI->getOperand(1);
-    OtherOpT = TI->getOperand(0);
-    OtherOpF = FI->getOperand(1);
-    MatchIsOpZero = true;
-  } else {
-    return 0;
-  }
-
-  // If we reach here, they do have operations in common.
-  SelectInst *NewSI = SelectInst::Create(SI.getCondition(), OtherOpT,
-                                         OtherOpF, SI.getName()+".v");
-  InsertNewInstBefore(NewSI, SI);
-
-  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(TI)) {
-    if (MatchIsOpZero)
-      return BinaryOperator::Create(BO->getOpcode(), MatchOp, NewSI);
-    else
-      return BinaryOperator::Create(BO->getOpcode(), NewSI, MatchOp);
-  }
-  llvm_unreachable("Shouldn't get here");
-  return 0;
-}
-
-static bool isSelect01(Constant *C1, Constant *C2) {
-  ConstantInt *C1I = dyn_cast<ConstantInt>(C1);
-  if (!C1I)
-    return false;
-  ConstantInt *C2I = dyn_cast<ConstantInt>(C2);
-  if (!C2I)
-    return false;
-  return (C1I->isZero() || C1I->isOne()) && (C2I->isZero() || C2I->isOne());
-}
-
-/// FoldSelectIntoOp - Try fold the select into one of the operands to
-/// facilitate further optimization.
-Instruction *InstCombiner::FoldSelectIntoOp(SelectInst &SI, Value *TrueVal,
-                                            Value *FalseVal) {
-  // See the comment above GetSelectFoldableOperands for a description of the
-  // transformation we are doing here.
-  if (Instruction *TVI = dyn_cast<Instruction>(TrueVal)) {
-    if (TVI->hasOneUse() && TVI->getNumOperands() == 2 &&
-        !isa<Constant>(FalseVal)) {
-      if (unsigned SFO = GetSelectFoldableOperands(TVI)) {
-        unsigned OpToFold = 0;
-        if ((SFO & 1) && FalseVal == TVI->getOperand(0)) {
-          OpToFold = 1;
-        } else  if ((SFO & 2) && FalseVal == TVI->getOperand(1)) {
-          OpToFold = 2;
-        }
-
-        if (OpToFold) {
-          Constant *C = GetSelectFoldableConstant(TVI, Context);
-          Value *OOp = TVI->getOperand(2-OpToFold);
-          // Avoid creating select between 2 constants unless it's selecting
-          // between 0 and 1.
-          if (!isa<Constant>(OOp) || isSelect01(C, cast<Constant>(OOp))) {
-            Instruction *NewSel = SelectInst::Create(SI.getCondition(), OOp, C);
-            InsertNewInstBefore(NewSel, SI);
-            NewSel->takeName(TVI);
-            if (BinaryOperator *BO = dyn_cast<BinaryOperator>(TVI))
-              return BinaryOperator::Create(BO->getOpcode(), FalseVal, NewSel);
-            llvm_unreachable("Unknown instruction!!");
-          }
-        }
-      }
-    }
-  }
-
-  if (Instruction *FVI = dyn_cast<Instruction>(FalseVal)) {
-    if (FVI->hasOneUse() && FVI->getNumOperands() == 2 &&
-        !isa<Constant>(TrueVal)) {
-      if (unsigned SFO = GetSelectFoldableOperands(FVI)) {
-        unsigned OpToFold = 0;
-        if ((SFO & 1) && TrueVal == FVI->getOperand(0)) {
-          OpToFold = 1;
-        } else  if ((SFO & 2) && TrueVal == FVI->getOperand(1)) {
-          OpToFold = 2;
-        }
-
-        if (OpToFold) {
-          Constant *C = GetSelectFoldableConstant(FVI, Context);
-          Value *OOp = FVI->getOperand(2-OpToFold);
-          // Avoid creating select between 2 constants unless it's selecting
-          // between 0 and 1.
-          if (!isa<Constant>(OOp) || isSelect01(C, cast<Constant>(OOp))) {
-            Instruction *NewSel = SelectInst::Create(SI.getCondition(), C, OOp);
-            InsertNewInstBefore(NewSel, SI);
-            NewSel->takeName(FVI);
-            if (BinaryOperator *BO = dyn_cast<BinaryOperator>(FVI))
-              return BinaryOperator::Create(BO->getOpcode(), TrueVal, NewSel);
-            llvm_unreachable("Unknown instruction!!");
-          }
-        }
-      }
-    }
-  }
-
-  return 0;
-}
-
-/// visitSelectInstWithICmp - Visit a SelectInst that has an
-/// ICmpInst as its first operand.
-///
-Instruction *InstCombiner::visitSelectInstWithICmp(SelectInst &SI,
-                                                   ICmpInst *ICI) {
-  bool Changed = false;
-  ICmpInst::Predicate Pred = ICI->getPredicate();
-  Value *CmpLHS = ICI->getOperand(0);
-  Value *CmpRHS = ICI->getOperand(1);
-  Value *TrueVal = SI.getTrueValue();
-  Value *FalseVal = SI.getFalseValue();
-
-  // Check cases where the comparison is with a constant that
-  // can be adjusted to fit the min/max idiom. We may edit ICI in
-  // place here, so make sure the select is the only user.
-  if (ICI->hasOneUse())
-    if (ConstantInt *CI = dyn_cast<ConstantInt>(CmpRHS)) {
-      switch (Pred) {
-      default: break;
-      case ICmpInst::ICMP_ULT:
-      case ICmpInst::ICMP_SLT: {
-        // X < MIN ? T : F  -->  F
-        if (CI->isMinValue(Pred == ICmpInst::ICMP_SLT))
-          return ReplaceInstUsesWith(SI, FalseVal);
-        // X < C ? X : C-1  -->  X > C-1 ? C-1 : X
-        Constant *AdjustedRHS = SubOne(CI);
-        if ((CmpLHS == TrueVal && AdjustedRHS == FalseVal) ||
-            (CmpLHS == FalseVal && AdjustedRHS == TrueVal)) {
-          Pred = ICmpInst::getSwappedPredicate(Pred);
-          CmpRHS = AdjustedRHS;
-          std::swap(FalseVal, TrueVal);
-          ICI->setPredicate(Pred);
-          ICI->setOperand(1, CmpRHS);
-          SI.setOperand(1, TrueVal);
-          SI.setOperand(2, FalseVal);
-          Changed = true;
-        }
-        break;
-      }
-      case ICmpInst::ICMP_UGT:
-      case ICmpInst::ICMP_SGT: {
-        // X > MAX ? T : F  -->  F
-        if (CI->isMaxValue(Pred == ICmpInst::ICMP_SGT))
-          return ReplaceInstUsesWith(SI, FalseVal);
-        // X > C ? X : C+1  -->  X < C+1 ? C+1 : X
-        Constant *AdjustedRHS = AddOne(CI);
-        if ((CmpLHS == TrueVal && AdjustedRHS == FalseVal) ||
-            (CmpLHS == FalseVal && AdjustedRHS == TrueVal)) {
-          Pred = ICmpInst::getSwappedPredicate(Pred);
-          CmpRHS = AdjustedRHS;
-          std::swap(FalseVal, TrueVal);
-          ICI->setPredicate(Pred);
-          ICI->setOperand(1, CmpRHS);
-          SI.setOperand(1, TrueVal);
-          SI.setOperand(2, FalseVal);
-          Changed = true;
-        }
-        break;
-      }
-      }
-
-      // (x <s 0) ? -1 : 0 -> ashr x, 31   -> all ones if signed
-      // (x >s -1) ? -1 : 0 -> ashr x, 31  -> all ones if not signed
-      CmpInst::Predicate Pred = CmpInst::BAD_ICMP_PREDICATE;
-      if (match(TrueVal, m_ConstantInt<-1>()) &&
-          match(FalseVal, m_ConstantInt<0>()))
-        Pred = ICI->getPredicate();
-      else if (match(TrueVal, m_ConstantInt<0>()) &&
-               match(FalseVal, m_ConstantInt<-1>()))
-        Pred = CmpInst::getInversePredicate(ICI->getPredicate());
-      
-      if (Pred != CmpInst::BAD_ICMP_PREDICATE) {
-        // If we are just checking for a icmp eq of a single bit and zext'ing it
-        // to an integer, then shift the bit to the appropriate place and then
-        // cast to integer to avoid the comparison.
-        const APInt &Op1CV = CI->getValue();
-    
-        // sext (x <s  0) to i32 --> x>>s31      true if signbit set.
-        // sext (x >s -1) to i32 --> (x>>s31)^-1  true if signbit clear.
-        if ((Pred == ICmpInst::ICMP_SLT && Op1CV == 0) ||
-            (Pred == ICmpInst::ICMP_SGT && Op1CV.isAllOnesValue())) {
-          Value *In = ICI->getOperand(0);
-          Value *Sh = ConstantInt::get(In->getType(),
-                                       In->getType()->getScalarSizeInBits()-1);
-          In = InsertNewInstBefore(BinaryOperator::CreateAShr(In, Sh,
-                                                        In->getName()+".lobit"),
-                                   *ICI);
-          if (In->getType() != SI.getType())
-            In = CastInst::CreateIntegerCast(In, SI.getType(),
-                                             true/*SExt*/, "tmp", ICI);
-    
-          if (Pred == ICmpInst::ICMP_SGT)
-            In = InsertNewInstBefore(BinaryOperator::CreateNot(In,
-                                       In->getName()+".not"), *ICI);
-    
-          return ReplaceInstUsesWith(SI, In);
-        }
-      }
-    }
-
-  if (CmpLHS == TrueVal && CmpRHS == FalseVal) {
-    // Transform (X == Y) ? X : Y  -> Y
-    if (Pred == ICmpInst::ICMP_EQ)
-      return ReplaceInstUsesWith(SI, FalseVal);
-    // Transform (X != Y) ? X : Y  -> X
-    if (Pred == ICmpInst::ICMP_NE)
-      return ReplaceInstUsesWith(SI, TrueVal);
-    /// NOTE: if we wanted to, this is where to detect integer MIN/MAX
-
-  } else if (CmpLHS == FalseVal && CmpRHS == TrueVal) {
-    // Transform (X == Y) ? Y : X  -> X
-    if (Pred == ICmpInst::ICMP_EQ)
-      return ReplaceInstUsesWith(SI, FalseVal);
-    // Transform (X != Y) ? Y : X  -> Y
-    if (Pred == ICmpInst::ICMP_NE)
-      return ReplaceInstUsesWith(SI, TrueVal);
-    /// NOTE: if we wanted to, this is where to detect integer MIN/MAX
-  }
-  return Changed ? &SI : 0;
-}
-
-
-/// CanSelectOperandBeMappingIntoPredBlock - SI is a select whose condition is a
-/// PHI node (but the two may be in different blocks).  See if the true/false
-/// values (V) are live in all of the predecessor blocks of the PHI.  For
-/// example, cases like this cannot be mapped:
-///
-///   X = phi [ C1, BB1], [C2, BB2]
-///   Y = add
-///   Z = select X, Y, 0
-///
-/// because Y is not live in BB1/BB2.
-///
-static bool CanSelectOperandBeMappingIntoPredBlock(const Value *V,
-                                                   const SelectInst &SI) {
-  // If the value is a non-instruction value like a constant or argument, it
-  // can always be mapped.
-  const Instruction *I = dyn_cast<Instruction>(V);
-  if (I == 0) return true;
-  
-  // If V is a PHI node defined in the same block as the condition PHI, we can
-  // map the arguments.
-  const PHINode *CondPHI = cast<PHINode>(SI.getCondition());
-  
-  if (const PHINode *VP = dyn_cast<PHINode>(I))
-    if (VP->getParent() == CondPHI->getParent())
-      return true;
-  
-  // Otherwise, if the PHI and select are defined in the same block and if V is
-  // defined in a different block, then we can transform it.
-  if (SI.getParent() == CondPHI->getParent() &&
-      I->getParent() != CondPHI->getParent())
-    return true;
-  
-  // Otherwise we have a 'hard' case and we can't tell without doing more
-  // detailed dominator based analysis, punt.
-  return false;
-}
-
-/// FoldSPFofSPF - We have an SPF (e.g. a min or max) of an SPF of the form:
-///   SPF2(SPF1(A, B), C) 
-Instruction *InstCombiner::FoldSPFofSPF(Instruction *Inner,
-                                        SelectPatternFlavor SPF1,
-                                        Value *A, Value *B,
-                                        Instruction &Outer,
-                                        SelectPatternFlavor SPF2, Value *C) {
-  if (C == A || C == B) {
-    // MAX(MAX(A, B), B) -> MAX(A, B)
-    // MIN(MIN(a, b), a) -> MIN(a, b)
-    if (SPF1 == SPF2)
-      return ReplaceInstUsesWith(Outer, Inner);
-    
-    // MAX(MIN(a, b), a) -> a
-    // MIN(MAX(a, b), a) -> a
-    if ((SPF1 == SPF_SMIN && SPF2 == SPF_SMAX) ||
-        (SPF1 == SPF_SMAX && SPF2 == SPF_SMIN) ||
-        (SPF1 == SPF_UMIN && SPF2 == SPF_UMAX) ||
-        (SPF1 == SPF_UMAX && SPF2 == SPF_UMIN))
-      return ReplaceInstUsesWith(Outer, C);
-  }
-  
-  // TODO: MIN(MIN(A, 23), 97)
-  return 0;
-}
-
-
-
-
-Instruction *InstCombiner::visitSelectInst(SelectInst &SI) {
-  Value *CondVal = SI.getCondition();
-  Value *TrueVal = SI.getTrueValue();
-  Value *FalseVal = SI.getFalseValue();
-
-  // select true, X, Y  -> X
-  // select false, X, Y -> Y
-  if (ConstantInt *C = dyn_cast<ConstantInt>(CondVal))
-    return ReplaceInstUsesWith(SI, C->getZExtValue() ? TrueVal : FalseVal);
-
-  // select C, X, X -> X
-  if (TrueVal == FalseVal)
-    return ReplaceInstUsesWith(SI, TrueVal);
-
-  if (isa<UndefValue>(TrueVal))   // select C, undef, X -> X
-    return ReplaceInstUsesWith(SI, FalseVal);
-  if (isa<UndefValue>(FalseVal))   // select C, X, undef -> X
-    return ReplaceInstUsesWith(SI, TrueVal);
-  if (isa<UndefValue>(CondVal)) {  // select undef, X, Y -> X or Y
-    if (isa<Constant>(TrueVal))
-      return ReplaceInstUsesWith(SI, TrueVal);
-    else
-      return ReplaceInstUsesWith(SI, FalseVal);
-  }
-
-  if (SI.getType() == Type::getInt1Ty(*Context)) {
-    if (ConstantInt *C = dyn_cast<ConstantInt>(TrueVal)) {
-      if (C->getZExtValue()) {
-        // Change: A = select B, true, C --> A = or B, C
-        return BinaryOperator::CreateOr(CondVal, FalseVal);
-      } else {
-        // Change: A = select B, false, C --> A = and !B, C
-        Value *NotCond =
-          InsertNewInstBefore(BinaryOperator::CreateNot(CondVal,
-                                             "not."+CondVal->getName()), SI);
-        return BinaryOperator::CreateAnd(NotCond, FalseVal);
-      }
-    } else if (ConstantInt *C = dyn_cast<ConstantInt>(FalseVal)) {
-      if (C->getZExtValue() == false) {
-        // Change: A = select B, C, false --> A = and B, C
-        return BinaryOperator::CreateAnd(CondVal, TrueVal);
-      } else {
-        // Change: A = select B, C, true --> A = or !B, C
-        Value *NotCond =
-          InsertNewInstBefore(BinaryOperator::CreateNot(CondVal,
-                                             "not."+CondVal->getName()), SI);
-        return BinaryOperator::CreateOr(NotCond, TrueVal);
-      }
-    }
-    
-    // select a, b, a  -> a&b
-    // select a, a, b  -> a|b
-    if (CondVal == TrueVal)
-      return BinaryOperator::CreateOr(CondVal, FalseVal);
-    else if (CondVal == FalseVal)
-      return BinaryOperator::CreateAnd(CondVal, TrueVal);
-  }
-
-  // Selecting between two integer constants?
-  if (ConstantInt *TrueValC = dyn_cast<ConstantInt>(TrueVal))
-    if (ConstantInt *FalseValC = dyn_cast<ConstantInt>(FalseVal)) {
-      // select C, 1, 0 -> zext C to int
-      if (FalseValC->isZero() && TrueValC->getValue() == 1) {
-        return CastInst::Create(Instruction::ZExt, CondVal, SI.getType());
-      } else if (TrueValC->isZero() && FalseValC->getValue() == 1) {
-        // select C, 0, 1 -> zext !C to int
-        Value *NotCond =
-          InsertNewInstBefore(BinaryOperator::CreateNot(CondVal,
-                                               "not."+CondVal->getName()), SI);
-        return CastInst::Create(Instruction::ZExt, NotCond, SI.getType());
-      }
-
-      if (ICmpInst *IC = dyn_cast<ICmpInst>(SI.getCondition())) {
-        // If one of the constants is zero (we know they can't both be) and we
-        // have an icmp instruction with zero, and we have an 'and' with the
-        // non-constant value, eliminate this whole mess.  This corresponds to
-        // cases like this: ((X & 27) ? 27 : 0)
-        if (TrueValC->isZero() || FalseValC->isZero())
-          if (IC->isEquality() && isa<ConstantInt>(IC->getOperand(1)) &&
-              cast<Constant>(IC->getOperand(1))->isNullValue())
-            if (Instruction *ICA = dyn_cast<Instruction>(IC->getOperand(0)))
-              if (ICA->getOpcode() == Instruction::And &&
-                  isa<ConstantInt>(ICA->getOperand(1)) &&
-                  (ICA->getOperand(1) == TrueValC ||
-                   ICA->getOperand(1) == FalseValC) &&
-                  isOneBitSet(cast<ConstantInt>(ICA->getOperand(1)))) {
-                // Okay, now we know that everything is set up, we just don't
-                // know whether we have a icmp_ne or icmp_eq and whether the 
-                // true or false val is the zero.
-                bool ShouldNotVal = !TrueValC->isZero();
-                ShouldNotVal ^= IC->getPredicate() == ICmpInst::ICMP_NE;
-                Value *V = ICA;
-                if (ShouldNotVal)
-                  V = InsertNewInstBefore(BinaryOperator::Create(
-                                  Instruction::Xor, V, ICA->getOperand(1)), SI);
-                return ReplaceInstUsesWith(SI, V);
-              }
-      }
-    }
-
-  // See if we are selecting two values based on a comparison of the two values.
-  if (FCmpInst *FCI = dyn_cast<FCmpInst>(CondVal)) {
-    if (FCI->getOperand(0) == TrueVal && FCI->getOperand(1) == FalseVal) {
-      // Transform (X == Y) ? X : Y  -> Y
-      if (FCI->getPredicate() == FCmpInst::FCMP_OEQ) {
-        // This is not safe in general for floating point:  
-        // consider X== -0, Y== +0.
-        // It becomes safe if either operand is a nonzero constant.
-        ConstantFP *CFPt, *CFPf;
-        if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) &&
-              !CFPt->getValueAPF().isZero()) ||
-            ((CFPf = dyn_cast<ConstantFP>(FalseVal)) &&
-             !CFPf->getValueAPF().isZero()))
-        return ReplaceInstUsesWith(SI, FalseVal);
-      }
-      // Transform (X != Y) ? X : Y  -> X
-      if (FCI->getPredicate() == FCmpInst::FCMP_ONE)
-        return ReplaceInstUsesWith(SI, TrueVal);
-      // NOTE: if we wanted to, this is where to detect MIN/MAX
-
-    } else if (FCI->getOperand(0) == FalseVal && FCI->getOperand(1) == TrueVal){
-      // Transform (X == Y) ? Y : X  -> X
-      if (FCI->getPredicate() == FCmpInst::FCMP_OEQ) {
-        // This is not safe in general for floating point:  
-        // consider X== -0, Y== +0.
-        // It becomes safe if either operand is a nonzero constant.
-        ConstantFP *CFPt, *CFPf;
-        if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) &&
-              !CFPt->getValueAPF().isZero()) ||
-            ((CFPf = dyn_cast<ConstantFP>(FalseVal)) &&
-             !CFPf->getValueAPF().isZero()))
-          return ReplaceInstUsesWith(SI, FalseVal);
-      }
-      // Transform (X != Y) ? Y : X  -> Y
-      if (FCI->getPredicate() == FCmpInst::FCMP_ONE)
-        return ReplaceInstUsesWith(SI, TrueVal);
-      // NOTE: if we wanted to, this is where to detect MIN/MAX
-    }
-    // NOTE: if we wanted to, this is where to detect ABS
-  }
-
-  // See if we are selecting two values based on a comparison of the two values.
-  if (ICmpInst *ICI = dyn_cast<ICmpInst>(CondVal))
-    if (Instruction *Result = visitSelectInstWithICmp(SI, ICI))
-      return Result;
-
-  if (Instruction *TI = dyn_cast<Instruction>(TrueVal))
-    if (Instruction *FI = dyn_cast<Instruction>(FalseVal))
-      if (TI->hasOneUse() && FI->hasOneUse()) {
-        Instruction *AddOp = 0, *SubOp = 0;
-
-        // Turn (select C, (op X, Y), (op X, Z)) -> (op X, (select C, Y, Z))
-        if (TI->getOpcode() == FI->getOpcode())
-          if (Instruction *IV = FoldSelectOpOp(SI, TI, FI))
-            return IV;
-
-        // Turn select C, (X+Y), (X-Y) --> (X+(select C, Y, (-Y))).  This is
-        // even legal for FP.
-        if ((TI->getOpcode() == Instruction::Sub &&
-             FI->getOpcode() == Instruction::Add) ||
-            (TI->getOpcode() == Instruction::FSub &&
-             FI->getOpcode() == Instruction::FAdd)) {
-          AddOp = FI; SubOp = TI;
-        } else if ((FI->getOpcode() == Instruction::Sub &&
-                    TI->getOpcode() == Instruction::Add) ||
-                   (FI->getOpcode() == Instruction::FSub &&
-                    TI->getOpcode() == Instruction::FAdd)) {
-          AddOp = TI; SubOp = FI;
-        }
-
-        if (AddOp) {
-          Value *OtherAddOp = 0;
-          if (SubOp->getOperand(0) == AddOp->getOperand(0)) {
-            OtherAddOp = AddOp->getOperand(1);
-          } else if (SubOp->getOperand(0) == AddOp->getOperand(1)) {
-            OtherAddOp = AddOp->getOperand(0);
-          }
-
-          if (OtherAddOp) {
-            // So at this point we know we have (Y -> OtherAddOp):
-            //        select C, (add X, Y), (sub X, Z)
-            Value *NegVal;  // Compute -Z
-            if (Constant *C = dyn_cast<Constant>(SubOp->getOperand(1))) {
-              NegVal = ConstantExpr::getNeg(C);
-            } else {
-              NegVal = InsertNewInstBefore(
-                    BinaryOperator::CreateNeg(SubOp->getOperand(1),
-                                              "tmp"), SI);
-            }
-
-            Value *NewTrueOp = OtherAddOp;
-            Value *NewFalseOp = NegVal;
-            if (AddOp != TI)
-              std::swap(NewTrueOp, NewFalseOp);
-            Instruction *NewSel =
-              SelectInst::Create(CondVal, NewTrueOp,
-                                 NewFalseOp, SI.getName() + ".p");
-
-            NewSel = InsertNewInstBefore(NewSel, SI);
-            return BinaryOperator::CreateAdd(SubOp->getOperand(0), NewSel);
-          }
-        }
-      }
-
-  // See if we can fold the select into one of our operands.
-  if (SI.getType()->isInteger()) {
-    if (Instruction *FoldI = FoldSelectIntoOp(SI, TrueVal, FalseVal))
-      return FoldI;
-    
-    // MAX(MAX(a, b), a) -> MAX(a, b)
-    // MIN(MIN(a, b), a) -> MIN(a, b)
-    // MAX(MIN(a, b), a) -> a
-    // MIN(MAX(a, b), a) -> a
-    Value *LHS, *RHS, *LHS2, *RHS2;
-    if (SelectPatternFlavor SPF = MatchSelectPattern(&SI, LHS, RHS)) {
-      if (SelectPatternFlavor SPF2 = MatchSelectPattern(LHS, LHS2, RHS2))
-        if (Instruction *R = FoldSPFofSPF(cast<Instruction>(LHS),SPF2,LHS2,RHS2, 
-                                          SI, SPF, RHS))
-          return R;
-      if (SelectPatternFlavor SPF2 = MatchSelectPattern(RHS, LHS2, RHS2))
-        if (Instruction *R = FoldSPFofSPF(cast<Instruction>(RHS),SPF2,LHS2,RHS2,
-                                          SI, SPF, LHS))
-          return R;
-    }
-
-    // TODO.
-    // ABS(-X) -> ABS(X)
-    // ABS(ABS(X)) -> ABS(X)
-  }
-
-  // See if we can fold the select into a phi node if the condition is a select.
-  if (isa<PHINode>(SI.getCondition())) 
-    // The true/false values have to be live in the PHI predecessor's blocks.
-    if (CanSelectOperandBeMappingIntoPredBlock(TrueVal, SI) &&
-        CanSelectOperandBeMappingIntoPredBlock(FalseVal, SI))
-      if (Instruction *NV = FoldOpIntoPhi(SI))
-        return NV;
-
-  if (BinaryOperator::isNot(CondVal)) {
-    SI.setOperand(0, BinaryOperator::getNotArgument(CondVal));
-    SI.setOperand(1, FalseVal);
-    SI.setOperand(2, TrueVal);
-    return &SI;
-  }
-
-  return 0;
-}
-
-/// EnforceKnownAlignment - If the specified pointer points to an object that
-/// we control, modify the object's alignment to PrefAlign. This isn't
-/// often possible though. If alignment is important, a more reliable approach
-/// is to simply align all global variables and allocation instructions to
-/// their preferred alignment from the beginning.
-///
-static unsigned EnforceKnownAlignment(Value *V,
-                                      unsigned Align, unsigned PrefAlign) {
-
-  User *U = dyn_cast<User>(V);
-  if (!U) return Align;
-
-  switch (Operator::getOpcode(U)) {
-  default: break;
-  case Instruction::BitCast:
-    return EnforceKnownAlignment(U->getOperand(0), Align, PrefAlign);
-  case Instruction::GetElementPtr: {
-    // If all indexes are zero, it is just the alignment of the base pointer.
-    bool AllZeroOperands = true;
-    for (User::op_iterator i = U->op_begin() + 1, e = U->op_end(); i != e; ++i)
-      if (!isa<Constant>(*i) ||
-          !cast<Constant>(*i)->isNullValue()) {
-        AllZeroOperands = false;
-        break;
-      }
-
-    if (AllZeroOperands) {
-      // Treat this like a bitcast.
-      return EnforceKnownAlignment(U->getOperand(0), Align, PrefAlign);
-    }
-    break;
-  }
-  }
-
-  if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
-    // If there is a large requested alignment and we can, bump up the alignment
-    // of the global.
-    if (!GV->isDeclaration()) {
-      if (GV->getAlignment() >= PrefAlign)
-        Align = GV->getAlignment();
-      else {
-        GV->setAlignment(PrefAlign);
-        Align = PrefAlign;
-      }
-    }
-  } else if (AllocaInst *AI = dyn_cast<AllocaInst>(V)) {
-    // If there is a requested alignment and if this is an alloca, round up.
-    if (AI->getAlignment() >= PrefAlign)
-      Align = AI->getAlignment();
-    else {
-      AI->setAlignment(PrefAlign);
-      Align = PrefAlign;
-    }
-  }
-
-  return Align;
-}
-
-/// GetOrEnforceKnownAlignment - If the specified pointer has an alignment that
-/// we can determine, return it, otherwise return 0.  If PrefAlign is specified,
-/// and it is more than the alignment of the ultimate object, see if we can
-/// increase the alignment of the ultimate object, making this check succeed.
-unsigned InstCombiner::GetOrEnforceKnownAlignment(Value *V,
-                                                  unsigned PrefAlign) {
-  unsigned BitWidth = TD ? TD->getTypeSizeInBits(V->getType()) :
-                      sizeof(PrefAlign) * CHAR_BIT;
-  APInt Mask = APInt::getAllOnesValue(BitWidth);
-  APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
-  ComputeMaskedBits(V, Mask, KnownZero, KnownOne);
-  unsigned TrailZ = KnownZero.countTrailingOnes();
-  unsigned Align = 1u << std::min(BitWidth - 1, TrailZ);
-
-  if (PrefAlign > Align)
-    Align = EnforceKnownAlignment(V, Align, PrefAlign);
-  
-    // We don't need to make any adjustment.
-  return Align;
-}
-
-Instruction *InstCombiner::SimplifyMemTransfer(MemIntrinsic *MI) {
-  unsigned DstAlign = GetOrEnforceKnownAlignment(MI->getOperand(1));
-  unsigned SrcAlign = GetOrEnforceKnownAlignment(MI->getOperand(2));
-  unsigned MinAlign = std::min(DstAlign, SrcAlign);
-  unsigned CopyAlign = MI->getAlignment();
-
-  if (CopyAlign < MinAlign) {
-    MI->setAlignment(ConstantInt::get(MI->getAlignmentType(), 
-                                             MinAlign, false));
-    return MI;
-  }
-  
-  // If MemCpyInst length is 1/2/4/8 bytes then replace memcpy with
-  // load/store.
-  ConstantInt *MemOpLength = dyn_cast<ConstantInt>(MI->getOperand(3));
-  if (MemOpLength == 0) return 0;
-  
-  // Source and destination pointer types are always "i8*" for intrinsic.  See
-  // if the size is something we can handle with a single primitive load/store.
-  // A single load+store correctly handles overlapping memory in the memmove
-  // case.
-  unsigned Size = MemOpLength->getZExtValue();
-  if (Size == 0) return MI;  // Delete this mem transfer.
-  
-  if (Size > 8 || (Size&(Size-1)))
-    return 0;  // If not 1/2/4/8 bytes, exit.
-  
-  // Use an integer load+store unless we can find something better.
-  Type *NewPtrTy =
-                PointerType::getUnqual(IntegerType::get(*Context, Size<<3));
-  
-  // Memcpy forces the use of i8* for the source and destination.  That means
-  // that if you're using memcpy to move one double around, you'll get a cast
-  // from double* to i8*.  We'd much rather use a double load+store rather than
-  // an i64 load+store, here because this improves the odds that the source or
-  // dest address will be promotable.  See if we can find a better type than the
-  // integer datatype.
-  if (Value *Op = getBitCastOperand(MI->getOperand(1))) {
-    const Type *SrcETy = cast<PointerType>(Op->getType())->getElementType();
-    if (TD && SrcETy->isSized() && TD->getTypeStoreSize(SrcETy) == Size) {
-      // The SrcETy might be something like {{{double}}} or [1 x double].  Rip
-      // down through these levels if so.
-      while (!SrcETy->isSingleValueType()) {
-        if (const StructType *STy = dyn_cast<StructType>(SrcETy)) {
-          if (STy->getNumElements() == 1)
-            SrcETy = STy->getElementType(0);
-          else
-            break;
-        } else if (const ArrayType *ATy = dyn_cast<ArrayType>(SrcETy)) {
-          if (ATy->getNumElements() == 1)
-            SrcETy = ATy->getElementType();
-          else
-            break;
-        } else
-          break;
-      }
-      
-      if (SrcETy->isSingleValueType())
-        NewPtrTy = PointerType::getUnqual(SrcETy);
-    }
-  }
-  
-  
-  // If the memcpy/memmove provides better alignment info than we can
-  // infer, use it.
-  SrcAlign = std::max(SrcAlign, CopyAlign);
-  DstAlign = std::max(DstAlign, CopyAlign);
-  
-  Value *Src = Builder->CreateBitCast(MI->getOperand(2), NewPtrTy);
-  Value *Dest = Builder->CreateBitCast(MI->getOperand(1), NewPtrTy);
-  Instruction *L = new LoadInst(Src, "tmp", false, SrcAlign);
-  InsertNewInstBefore(L, *MI);
-  InsertNewInstBefore(new StoreInst(L, Dest, false, DstAlign), *MI);
-
-  // Set the size of the copy to 0, it will be deleted on the next iteration.
-  MI->setOperand(3, Constant::getNullValue(MemOpLength->getType()));
-  return MI;
-}
-
-Instruction *InstCombiner::SimplifyMemSet(MemSetInst *MI) {
-  unsigned Alignment = GetOrEnforceKnownAlignment(MI->getDest());
-  if (MI->getAlignment() < Alignment) {
-    MI->setAlignment(ConstantInt::get(MI->getAlignmentType(),
-                                             Alignment, false));
-    return MI;
-  }
-  
-  // Extract the length and alignment and fill if they are constant.
-  ConstantInt *LenC = dyn_cast<ConstantInt>(MI->getLength());
-  ConstantInt *FillC = dyn_cast<ConstantInt>(MI->getValue());
-  if (!LenC || !FillC || FillC->getType() != Type::getInt8Ty(*Context))
-    return 0;
-  uint64_t Len = LenC->getZExtValue();
-  Alignment = MI->getAlignment();
-  
-  // If the length is zero, this is a no-op
-  if (Len == 0) return MI; // memset(d,c,0,a) -> noop
-  
-  // memset(s,c,n) -> store s, c (for n=1,2,4,8)
-  if (Len <= 8 && isPowerOf2_32((uint32_t)Len)) {
-    const Type *ITy = IntegerType::get(*Context, Len*8);  // n=1 -> i8.
-    
-    Value *Dest = MI->getDest();
-    Dest = Builder->CreateBitCast(Dest, PointerType::getUnqual(ITy));
-
-    // Alignment 0 is identity for alignment 1 for memset, but not store.
-    if (Alignment == 0) Alignment = 1;
-    
-    // Extract the fill value and store.
-    uint64_t Fill = FillC->getZExtValue()*0x0101010101010101ULL;
-    InsertNewInstBefore(new StoreInst(ConstantInt::get(ITy, Fill),
-                                      Dest, false, Alignment), *MI);
-    
-    // Set the size of the copy to 0, it will be deleted on the next iteration.
-    MI->setLength(Constant::getNullValue(LenC->getType()));
-    return MI;
-  }
-
-  return 0;
-}
-
-
-/// visitCallInst - CallInst simplification.  This mostly only handles folding 
-/// of intrinsic instructions.  For normal calls, it allows visitCallSite to do
-/// the heavy lifting.
-///
-Instruction *InstCombiner::visitCallInst(CallInst &CI) {
-  if (isFreeCall(&CI))
-    return visitFree(CI);
-
-  // If the caller function is nounwind, mark the call as nounwind, even if the
-  // callee isn't.
-  if (CI.getParent()->getParent()->doesNotThrow() &&
-      !CI.doesNotThrow()) {
-    CI.setDoesNotThrow();
-    return &CI;
-  }
-  
-  IntrinsicInst *II = dyn_cast<IntrinsicInst>(&CI);
-  if (!II) return visitCallSite(&CI);
-  
-  // Intrinsics cannot occur in an invoke, so handle them here instead of in
-  // visitCallSite.
-  if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(II)) {
-    bool Changed = false;
-
-    // memmove/cpy/set of zero bytes is a noop.
-    if (Constant *NumBytes = dyn_cast<Constant>(MI->getLength())) {
-      if (NumBytes->isNullValue()) return EraseInstFromFunction(CI);
-
-      if (ConstantInt *CI = dyn_cast<ConstantInt>(NumBytes))
-        if (CI->getZExtValue() == 1) {
-          // Replace the instruction with just byte operations.  We would
-          // transform other cases to loads/stores, but we don't know if
-          // alignment is sufficient.
-        }
-    }
-
-    // If we have a memmove and the source operation is a constant global,
-    // then the source and dest pointers can't alias, so we can change this
-    // into a call to memcpy.
-    if (MemMoveInst *MMI = dyn_cast<MemMoveInst>(MI)) {
-      if (GlobalVariable *GVSrc = dyn_cast<GlobalVariable>(MMI->getSource()))
-        if (GVSrc->isConstant()) {
-          Module *M = CI.getParent()->getParent()->getParent();
-          Intrinsic::ID MemCpyID = Intrinsic::memcpy;
-          const Type *Tys[1];
-          Tys[0] = CI.getOperand(3)->getType();
-          CI.setOperand(0, 
-                        Intrinsic::getDeclaration(M, MemCpyID, Tys, 1));
-          Changed = true;
-        }
-    }
-
-    if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(MI)) {
-      // memmove(x,x,size) -> noop.
-      if (MTI->getSource() == MTI->getDest())
-        return EraseInstFromFunction(CI);
-    }
-
-    // If we can determine a pointer alignment that is bigger than currently
-    // set, update the alignment.
-    if (isa<MemTransferInst>(MI)) {
-      if (Instruction *I = SimplifyMemTransfer(MI))
-        return I;
-    } else if (MemSetInst *MSI = dyn_cast<MemSetInst>(MI)) {
-      if (Instruction *I = SimplifyMemSet(MSI))
-        return I;
-    }
-          
-    if (Changed) return II;
-  }
-  
-  switch (II->getIntrinsicID()) {
-  default: break;
-  case Intrinsic::bswap:
-    // bswap(bswap(x)) -> x
-    if (IntrinsicInst *Operand = dyn_cast<IntrinsicInst>(II->getOperand(1)))
-      if (Operand->getIntrinsicID() == Intrinsic::bswap)
-        return ReplaceInstUsesWith(CI, Operand->getOperand(1));
-      
-    // bswap(trunc(bswap(x))) -> trunc(lshr(x, c))
-    if (TruncInst *TI = dyn_cast<TruncInst>(II->getOperand(1))) {
-      if (IntrinsicInst *Operand = dyn_cast<IntrinsicInst>(TI->getOperand(0)))
-        if (Operand->getIntrinsicID() == Intrinsic::bswap) {
-          unsigned C = Operand->getType()->getPrimitiveSizeInBits() -
-                       TI->getType()->getPrimitiveSizeInBits();
-          Value *CV = ConstantInt::get(Operand->getType(), C);
-          Value *V = Builder->CreateLShr(Operand->getOperand(1), CV);
-          return new TruncInst(V, TI->getType());
-        }
-    }
-      
-    break;
-  case Intrinsic::powi:
-    if (ConstantInt *Power = dyn_cast<ConstantInt>(II->getOperand(2))) {
-      // powi(x, 0) -> 1.0
-      if (Power->isZero())
-        return ReplaceInstUsesWith(CI, ConstantFP::get(CI.getType(), 1.0));
-      // powi(x, 1) -> x
-      if (Power->isOne())
-        return ReplaceInstUsesWith(CI, II->getOperand(1));
-      // powi(x, -1) -> 1/x
-      if (Power->isAllOnesValue())
-        return BinaryOperator::CreateFDiv(ConstantFP::get(CI.getType(), 1.0),
-                                          II->getOperand(1));
-    }
-    break;
-      
-  case Intrinsic::uadd_with_overflow: {
-    Value *LHS = II->getOperand(1), *RHS = II->getOperand(2);
-    const IntegerType *IT = cast<IntegerType>(II->getOperand(1)->getType());
-    uint32_t BitWidth = IT->getBitWidth();
-    APInt Mask = APInt::getSignBit(BitWidth);
-    APInt LHSKnownZero(BitWidth, 0);
-    APInt LHSKnownOne(BitWidth, 0);
-    ComputeMaskedBits(LHS, Mask, LHSKnownZero, LHSKnownOne);
-    bool LHSKnownNegative = LHSKnownOne[BitWidth - 1];
-    bool LHSKnownPositive = LHSKnownZero[BitWidth - 1];
-
-    if (LHSKnownNegative || LHSKnownPositive) {
-      APInt RHSKnownZero(BitWidth, 0);
-      APInt RHSKnownOne(BitWidth, 0);
-      ComputeMaskedBits(RHS, Mask, RHSKnownZero, RHSKnownOne);
-      bool RHSKnownNegative = RHSKnownOne[BitWidth - 1];
-      bool RHSKnownPositive = RHSKnownZero[BitWidth - 1];
-      if (LHSKnownNegative && RHSKnownNegative) {
-        // The sign bit is set in both cases: this MUST overflow.
-        // Create a simple add instruction, and insert it into the struct.
-        Instruction *Add = BinaryOperator::CreateAdd(LHS, RHS, "", &CI);
-        Worklist.Add(Add);
-        Constant *V[] = {
-          UndefValue::get(LHS->getType()), ConstantInt::getTrue(*Context)
-        };
-        Constant *Struct = ConstantStruct::get(*Context, V, 2, false);
-        return InsertValueInst::Create(Struct, Add, 0);
-      }
-      
-      if (LHSKnownPositive && RHSKnownPositive) {
-        // The sign bit is clear in both cases: this CANNOT overflow.
-        // Create a simple add instruction, and insert it into the struct.
-        Instruction *Add = BinaryOperator::CreateNUWAdd(LHS, RHS, "", &CI);
-        Worklist.Add(Add);
-        Constant *V[] = {
-          UndefValue::get(LHS->getType()), ConstantInt::getFalse(*Context)
-        };
-        Constant *Struct = ConstantStruct::get(*Context, V, 2, false);
-        return InsertValueInst::Create(Struct, Add, 0);
-      }
-    }
-  }
-  // FALL THROUGH uadd into sadd
-  case Intrinsic::sadd_with_overflow:
-    // Canonicalize constants into the RHS.
-    if (isa<Constant>(II->getOperand(1)) &&
-        !isa<Constant>(II->getOperand(2))) {
-      Value *LHS = II->getOperand(1);
-      II->setOperand(1, II->getOperand(2));
-      II->setOperand(2, LHS);
-      return II;
-    }
-
-    // X + undef -> undef
-    if (isa<UndefValue>(II->getOperand(2)))
-      return ReplaceInstUsesWith(CI, UndefValue::get(II->getType()));
-      
-    if (ConstantInt *RHS = dyn_cast<ConstantInt>(II->getOperand(2))) {
-      // X + 0 -> {X, false}
-      if (RHS->isZero()) {
-        Constant *V[] = {
-          UndefValue::get(II->getOperand(0)->getType()),
-          ConstantInt::getFalse(*Context)
-        };
-        Constant *Struct = ConstantStruct::get(*Context, V, 2, false);
-        return InsertValueInst::Create(Struct, II->getOperand(1), 0);
-      }
-    }
-    break;
-  case Intrinsic::usub_with_overflow:
-  case Intrinsic::ssub_with_overflow:
-    // undef - X -> undef
-    // X - undef -> undef
-    if (isa<UndefValue>(II->getOperand(1)) ||
-        isa<UndefValue>(II->getOperand(2)))
-      return ReplaceInstUsesWith(CI, UndefValue::get(II->getType()));
-      
-    if (ConstantInt *RHS = dyn_cast<ConstantInt>(II->getOperand(2))) {
-      // X - 0 -> {X, false}
-      if (RHS->isZero()) {
-        Constant *V[] = {
-          UndefValue::get(II->getOperand(1)->getType()),
-          ConstantInt::getFalse(*Context)
-        };
-        Constant *Struct = ConstantStruct::get(*Context, V, 2, false);
-        return InsertValueInst::Create(Struct, II->getOperand(1), 0);
-      }
-    }
-    break;
-  case Intrinsic::umul_with_overflow:
-  case Intrinsic::smul_with_overflow:
-    // Canonicalize constants into the RHS.
-    if (isa<Constant>(II->getOperand(1)) &&
-        !isa<Constant>(II->getOperand(2))) {
-      Value *LHS = II->getOperand(1);
-      II->setOperand(1, II->getOperand(2));
-      II->setOperand(2, LHS);
-      return II;
-    }
-
-    // X * undef -> undef
-    if (isa<UndefValue>(II->getOperand(2)))
-      return ReplaceInstUsesWith(CI, UndefValue::get(II->getType()));
-      
-    if (ConstantInt *RHSI = dyn_cast<ConstantInt>(II->getOperand(2))) {
-      // X*0 -> {0, false}
-      if (RHSI->isZero())
-        return ReplaceInstUsesWith(CI, Constant::getNullValue(II->getType()));
-      
-      // X * 1 -> {X, false}
-      if (RHSI->equalsInt(1)) {
-        Constant *V[] = {
-          UndefValue::get(II->getOperand(1)->getType()),
-          ConstantInt::getFalse(*Context)
-        };
-        Constant *Struct = ConstantStruct::get(*Context, V, 2, false);
-        return InsertValueInst::Create(Struct, II->getOperand(1), 0);
-      }
-    }
-    break;
-  case Intrinsic::ppc_altivec_lvx:
-  case Intrinsic::ppc_altivec_lvxl:
-  case Intrinsic::x86_sse_loadu_ps:
-  case Intrinsic::x86_sse2_loadu_pd:
-  case Intrinsic::x86_sse2_loadu_dq:
-    // Turn PPC lvx     -> load if the pointer is known aligned.
-    // Turn X86 loadups -> load if the pointer is known aligned.
-    if (GetOrEnforceKnownAlignment(II->getOperand(1), 16) >= 16) {
-      Value *Ptr = Builder->CreateBitCast(II->getOperand(1),
-                                         PointerType::getUnqual(II->getType()));
-      return new LoadInst(Ptr);
-    }
-    break;
-  case Intrinsic::ppc_altivec_stvx:
-  case Intrinsic::ppc_altivec_stvxl:
-    // Turn stvx -> store if the pointer is known aligned.
-    if (GetOrEnforceKnownAlignment(II->getOperand(2), 16) >= 16) {
-      const Type *OpPtrTy = 
-        PointerType::getUnqual(II->getOperand(1)->getType());
-      Value *Ptr = Builder->CreateBitCast(II->getOperand(2), OpPtrTy);
-      return new StoreInst(II->getOperand(1), Ptr);
-    }
-    break;
-  case Intrinsic::x86_sse_storeu_ps:
-  case Intrinsic::x86_sse2_storeu_pd:
-  case Intrinsic::x86_sse2_storeu_dq:
-    // Turn X86 storeu -> store if the pointer is known aligned.
-    if (GetOrEnforceKnownAlignment(II->getOperand(1), 16) >= 16) {
-      const Type *OpPtrTy = 
-        PointerType::getUnqual(II->getOperand(2)->getType());
-      Value *Ptr = Builder->CreateBitCast(II->getOperand(1), OpPtrTy);
-      return new StoreInst(II->getOperand(2), Ptr);
-    }
-    break;
-    
-  case Intrinsic::x86_sse_cvttss2si: {
-    // These intrinsics only demands the 0th element of its input vector.  If
-    // we can simplify the input based on that, do so now.
-    unsigned VWidth =
-      cast<VectorType>(II->getOperand(1)->getType())->getNumElements();
-    APInt DemandedElts(VWidth, 1);
-    APInt UndefElts(VWidth, 0);
-    if (Value *V = SimplifyDemandedVectorElts(II->getOperand(1), DemandedElts,
-                                              UndefElts)) {
-      II->setOperand(1, V);
-      return II;
-    }
-    break;
-  }
-    
-  case Intrinsic::ppc_altivec_vperm:
-    // Turn vperm(V1,V2,mask) -> shuffle(V1,V2,mask) if mask is a constant.
-    if (ConstantVector *Mask = dyn_cast<ConstantVector>(II->getOperand(3))) {
-      assert(Mask->getNumOperands() == 16 && "Bad type for intrinsic!");
-      
-      // Check that all of the elements are integer constants or undefs.
-      bool AllEltsOk = true;
-      for (unsigned i = 0; i != 16; ++i) {
-        if (!isa<ConstantInt>(Mask->getOperand(i)) && 
-            !isa<UndefValue>(Mask->getOperand(i))) {
-          AllEltsOk = false;
-          break;
-        }
-      }
-      
-      if (AllEltsOk) {
-        // Cast the input vectors to byte vectors.
-        Value *Op0 = Builder->CreateBitCast(II->getOperand(1), Mask->getType());
-        Value *Op1 = Builder->CreateBitCast(II->getOperand(2), Mask->getType());
-        Value *Result = UndefValue::get(Op0->getType());
-        
-        // Only extract each element once.
-        Value *ExtractedElts[32];
-        memset(ExtractedElts, 0, sizeof(ExtractedElts));
-        
-        for (unsigned i = 0; i != 16; ++i) {
-          if (isa<UndefValue>(Mask->getOperand(i)))
-            continue;
-          unsigned Idx=cast<ConstantInt>(Mask->getOperand(i))->getZExtValue();
-          Idx &= 31;  // Match the hardware behavior.
-          
-          if (ExtractedElts[Idx] == 0) {
-            ExtractedElts[Idx] = 
-              Builder->CreateExtractElement(Idx < 16 ? Op0 : Op1, 
-                  ConstantInt::get(Type::getInt32Ty(*Context), Idx&15, false),
-                                            "tmp");
-          }
-        
-          // Insert this value into the result vector.
-          Result = Builder->CreateInsertElement(Result, ExtractedElts[Idx],
-                         ConstantInt::get(Type::getInt32Ty(*Context), i, false),
-                                                "tmp");
-        }
-        return CastInst::Create(Instruction::BitCast, Result, CI.getType());
-      }
-    }
-    break;
-
-  case Intrinsic::stackrestore: {
-    // If the save is right next to the restore, remove the restore.  This can
-    // happen when variable allocas are DCE'd.
-    if (IntrinsicInst *SS = dyn_cast<IntrinsicInst>(II->getOperand(1))) {
-      if (SS->getIntrinsicID() == Intrinsic::stacksave) {
-        BasicBlock::iterator BI = SS;
-        if (&*++BI == II)
-          return EraseInstFromFunction(CI);
-      }
-    }
-    
-    // Scan down this block to see if there is another stack restore in the
-    // same block without an intervening call/alloca.
-    BasicBlock::iterator BI = II;
-    TerminatorInst *TI = II->getParent()->getTerminator();
-    bool CannotRemove = false;
-    for (++BI; &*BI != TI; ++BI) {
-      if (isa<AllocaInst>(BI) || isMalloc(BI)) {
-        CannotRemove = true;
-        break;
-      }
-      if (CallInst *BCI = dyn_cast<CallInst>(BI)) {
-        if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(BCI)) {
-          // If there is a stackrestore below this one, remove this one.
-          if (II->getIntrinsicID() == Intrinsic::stackrestore)
-            return EraseInstFromFunction(CI);
-          // Otherwise, ignore the intrinsic.
-        } else {
-          // If we found a non-intrinsic call, we can't remove the stack
-          // restore.
-          CannotRemove = true;
-          break;
-        }
-      }
-    }
-    
-    // If the stack restore is in a return/unwind block and if there are no
-    // allocas or calls between the restore and the return, nuke the restore.
-    if (!CannotRemove && (isa<ReturnInst>(TI) || isa<UnwindInst>(TI)))
-      return EraseInstFromFunction(CI);
-    break;
-  }
-  }
-
-  return visitCallSite(II);
-}
-
-// InvokeInst simplification
-//
-Instruction *InstCombiner::visitInvokeInst(InvokeInst &II) {
-  return visitCallSite(&II);
-}
-
-/// isSafeToEliminateVarargsCast - If this cast does not affect the value 
-/// passed through the varargs area, we can eliminate the use of the cast.
-static bool isSafeToEliminateVarargsCast(const CallSite CS,
-                                         const CastInst * const CI,
-                                         const TargetData * const TD,
-                                         const int ix) {
-  if (!CI->isLosslessCast())
-    return false;
-
-  // The size of ByVal arguments is derived from the type, so we
-  // can't change to a type with a different size.  If the size were
-  // passed explicitly we could avoid this check.
-  if (!CS.paramHasAttr(ix, Attribute::ByVal))
-    return true;
-
-  const Type* SrcTy = 
-            cast<PointerType>(CI->getOperand(0)->getType())->getElementType();
-  const Type* DstTy = cast<PointerType>(CI->getType())->getElementType();
-  if (!SrcTy->isSized() || !DstTy->isSized())
-    return false;
-  if (!TD || TD->getTypeAllocSize(SrcTy) != TD->getTypeAllocSize(DstTy))
-    return false;
-  return true;
-}
-
-// visitCallSite - Improvements for call and invoke instructions.
-//
-Instruction *InstCombiner::visitCallSite(CallSite CS) {
-  bool Changed = false;
-
-  // If the callee is a constexpr cast of a function, attempt to move the cast
-  // to the arguments of the call/invoke.
-  if (transformConstExprCastCall(CS)) return 0;
-
-  Value *Callee = CS.getCalledValue();
-
-  if (Function *CalleeF = dyn_cast<Function>(Callee))
-    if (CalleeF->getCallingConv() != CS.getCallingConv()) {
-      Instruction *OldCall = CS.getInstruction();
-      // If the call and callee calling conventions don't match, this call must
-      // be unreachable, as the call is undefined.
-      new StoreInst(ConstantInt::getTrue(*Context),
-                UndefValue::get(Type::getInt1PtrTy(*Context)), 
-                                  OldCall);
-      // If OldCall dues not return void then replaceAllUsesWith undef.
-      // This allows ValueHandlers and custom metadata to adjust itself.
-      if (!OldCall->getType()->isVoidTy())
-        OldCall->replaceAllUsesWith(UndefValue::get(OldCall->getType()));
-      if (isa<CallInst>(OldCall))   // Not worth removing an invoke here.
-        return EraseInstFromFunction(*OldCall);
-      return 0;
-    }
-
-  if (isa<ConstantPointerNull>(Callee) || isa<UndefValue>(Callee)) {
-    // This instruction is not reachable, just remove it.  We insert a store to
-    // undef so that we know that this code is not reachable, despite the fact
-    // that we can't modify the CFG here.
-    new StoreInst(ConstantInt::getTrue(*Context),
-               UndefValue::get(Type::getInt1PtrTy(*Context)),
-                  CS.getInstruction());
-
-    // If CS dues not return void then replaceAllUsesWith undef.
-    // This allows ValueHandlers and custom metadata to adjust itself.
-    if (!CS.getInstruction()->getType()->isVoidTy())
-      CS.getInstruction()->
-        replaceAllUsesWith(UndefValue::get(CS.getInstruction()->getType()));
-
-    if (InvokeInst *II = dyn_cast<InvokeInst>(CS.getInstruction())) {
-      // Don't break the CFG, insert a dummy cond branch.
-      BranchInst::Create(II->getNormalDest(), II->getUnwindDest(),
-                         ConstantInt::getTrue(*Context), II);
-    }
-    return EraseInstFromFunction(*CS.getInstruction());
-  }
-
-  if (BitCastInst *BC = dyn_cast<BitCastInst>(Callee))
-    if (IntrinsicInst *In = dyn_cast<IntrinsicInst>(BC->getOperand(0)))
-      if (In->getIntrinsicID() == Intrinsic::init_trampoline)
-        return transformCallThroughTrampoline(CS);
-
-  const PointerType *PTy = cast<PointerType>(Callee->getType());
-  const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
-  if (FTy->isVarArg()) {
-    int ix = FTy->getNumParams() + (isa<InvokeInst>(Callee) ? 3 : 1);
-    // See if we can optimize any arguments passed through the varargs area of
-    // the call.
-    for (CallSite::arg_iterator I = CS.arg_begin()+FTy->getNumParams(),
-           E = CS.arg_end(); I != E; ++I, ++ix) {
-      CastInst *CI = dyn_cast<CastInst>(*I);
-      if (CI && isSafeToEliminateVarargsCast(CS, CI, TD, ix)) {
-        *I = CI->getOperand(0);
-        Changed = true;
-      }
-    }
-  }
-
-  if (isa<InlineAsm>(Callee) && !CS.doesNotThrow()) {
-    // Inline asm calls cannot throw - mark them 'nounwind'.
-    CS.setDoesNotThrow();
-    Changed = true;
-  }
-
-  return Changed ? CS.getInstruction() : 0;
-}
-
-// transformConstExprCastCall - If the callee is a constexpr cast of a function,
-// attempt to move the cast to the arguments of the call/invoke.
-//
-bool InstCombiner::transformConstExprCastCall(CallSite CS) {
-  if (!isa<ConstantExpr>(CS.getCalledValue())) return false;
-  ConstantExpr *CE = cast<ConstantExpr>(CS.getCalledValue());
-  if (CE->getOpcode() != Instruction::BitCast || 
-      !isa<Function>(CE->getOperand(0)))
-    return false;
-  Function *Callee = cast<Function>(CE->getOperand(0));
-  Instruction *Caller = CS.getInstruction();
-  const AttrListPtr &CallerPAL = CS.getAttributes();
-
-  // Okay, this is a cast from a function to a different type.  Unless doing so
-  // would cause a type conversion of one of our arguments, change this call to
-  // be a direct call with arguments casted to the appropriate types.
-  //
-  const FunctionType *FT = Callee->getFunctionType();
-  const Type *OldRetTy = Caller->getType();
-  const Type *NewRetTy = FT->getReturnType();
-
-  if (isa<StructType>(NewRetTy))
-    return false; // TODO: Handle multiple return values.
-
-  // Check to see if we are changing the return type...
-  if (OldRetTy != NewRetTy) {
-    if (Callee->isDeclaration() &&
-        // Conversion is ok if changing from one pointer type to another or from
-        // a pointer to an integer of the same size.
-        !((isa<PointerType>(OldRetTy) || !TD ||
-           OldRetTy == TD->getIntPtrType(Caller->getContext())) &&
-          (isa<PointerType>(NewRetTy) || !TD ||
-           NewRetTy == TD->getIntPtrType(Caller->getContext()))))
-      return false;   // Cannot transform this return value.
-
-    if (!Caller->use_empty() &&
-        // void -> non-void is handled specially
-        !NewRetTy->isVoidTy() && !CastInst::isCastable(NewRetTy, OldRetTy))
-      return false;   // Cannot transform this return value.
-
-    if (!CallerPAL.isEmpty() && !Caller->use_empty()) {
-      Attributes RAttrs = CallerPAL.getRetAttributes();
-      if (RAttrs & Attribute::typeIncompatible(NewRetTy))
-        return false;   // Attribute not compatible with transformed value.
-    }
-
-    // If the callsite is an invoke instruction, and the return value is used by
-    // a PHI node in a successor, we cannot change the return type of the call
-    // because there is no place to put the cast instruction (without breaking
-    // the critical edge).  Bail out in this case.
-    if (!Caller->use_empty())
-      if (InvokeInst *II = dyn_cast<InvokeInst>(Caller))
-        for (Value::use_iterator UI = II->use_begin(), E = II->use_end();
-             UI != E; ++UI)
-          if (PHINode *PN = dyn_cast<PHINode>(*UI))
-            if (PN->getParent() == II->getNormalDest() ||
-                PN->getParent() == II->getUnwindDest())
-              return false;
-  }
-
-  unsigned NumActualArgs = unsigned(CS.arg_end()-CS.arg_begin());
-  unsigned NumCommonArgs = std::min(FT->getNumParams(), NumActualArgs);
-
-  CallSite::arg_iterator AI = CS.arg_begin();
-  for (unsigned i = 0, e = NumCommonArgs; i != e; ++i, ++AI) {
-    const Type *ParamTy = FT->getParamType(i);
-    const Type *ActTy = (*AI)->getType();
-
-    if (!CastInst::isCastable(ActTy, ParamTy))
-      return false;   // Cannot transform this parameter value.
-
-    if (CallerPAL.getParamAttributes(i + 1) 
-        & Attribute::typeIncompatible(ParamTy))
-      return false;   // Attribute not compatible with transformed value.
-
-    // Converting from one pointer type to another or between a pointer and an
-    // integer of the same size is safe even if we do not have a body.
-    bool isConvertible = ActTy == ParamTy ||
-      (TD && ((isa<PointerType>(ParamTy) ||
-      ParamTy == TD->getIntPtrType(Caller->getContext())) &&
-              (isa<PointerType>(ActTy) ||
-              ActTy == TD->getIntPtrType(Caller->getContext()))));
-    if (Callee->isDeclaration() && !isConvertible) return false;
-  }
-
-  if (FT->getNumParams() < NumActualArgs && !FT->isVarArg() &&
-      Callee->isDeclaration())
-    return false;   // Do not delete arguments unless we have a function body.
-
-  if (FT->getNumParams() < NumActualArgs && FT->isVarArg() &&
-      !CallerPAL.isEmpty())
-    // In this case we have more arguments than the new function type, but we
-    // won't be dropping them.  Check that these extra arguments have attributes
-    // that are compatible with being a vararg call argument.
-    for (unsigned i = CallerPAL.getNumSlots(); i; --i) {
-      if (CallerPAL.getSlot(i - 1).Index <= FT->getNumParams())
-        break;
-      Attributes PAttrs = CallerPAL.getSlot(i - 1).Attrs;
-      if (PAttrs & Attribute::VarArgsIncompatible)
-        return false;
-    }
-
-  // Okay, we decided that this is a safe thing to do: go ahead and start
-  // inserting cast instructions as necessary...
-  std::vector<Value*> Args;
-  Args.reserve(NumActualArgs);
-  SmallVector<AttributeWithIndex, 8> attrVec;
-  attrVec.reserve(NumCommonArgs);
-
-  // Get any return attributes.
-  Attributes RAttrs = CallerPAL.getRetAttributes();
-
-  // If the return value is not being used, the type may not be compatible
-  // with the existing attributes.  Wipe out any problematic attributes.
-  RAttrs &= ~Attribute::typeIncompatible(NewRetTy);
-
-  // Add the new return attributes.
-  if (RAttrs)
-    attrVec.push_back(AttributeWithIndex::get(0, RAttrs));
-
-  AI = CS.arg_begin();
-  for (unsigned i = 0; i != NumCommonArgs; ++i, ++AI) {
-    const Type *ParamTy = FT->getParamType(i);
-    if ((*AI)->getType() == ParamTy) {
-      Args.push_back(*AI);
-    } else {
-      Instruction::CastOps opcode = CastInst::getCastOpcode(*AI,
-          false, ParamTy, false);
-      Args.push_back(Builder->CreateCast(opcode, *AI, ParamTy, "tmp"));
-    }
-
-    // Add any parameter attributes.
-    if (Attributes PAttrs = CallerPAL.getParamAttributes(i + 1))
-      attrVec.push_back(AttributeWithIndex::get(i + 1, PAttrs));
-  }
-
-  // If the function takes more arguments than the call was taking, add them
-  // now.
-  for (unsigned i = NumCommonArgs; i != FT->getNumParams(); ++i)
-    Args.push_back(Constant::getNullValue(FT->getParamType(i)));
-
-  // If we are removing arguments to the function, emit an obnoxious warning.
-  if (FT->getNumParams() < NumActualArgs) {
-    if (!FT->isVarArg()) {
-      errs() << "WARNING: While resolving call to function '"
-             << Callee->getName() << "' arguments were dropped!\n";
-    } else {
-      // Add all of the arguments in their promoted form to the arg list.
-      for (unsigned i = FT->getNumParams(); i != NumActualArgs; ++i, ++AI) {
-        const Type *PTy = getPromotedType((*AI)->getType());
-        if (PTy != (*AI)->getType()) {
-          // Must promote to pass through va_arg area!
-          Instruction::CastOps opcode =
-            CastInst::getCastOpcode(*AI, false, PTy, false);
-          Args.push_back(Builder->CreateCast(opcode, *AI, PTy, "tmp"));
-        } else {
-          Args.push_back(*AI);
-        }
-
-        // Add any parameter attributes.
-        if (Attributes PAttrs = CallerPAL.getParamAttributes(i + 1))
-          attrVec.push_back(AttributeWithIndex::get(i + 1, PAttrs));
-      }
-    }
-  }
-
-  if (Attributes FnAttrs =  CallerPAL.getFnAttributes())
-    attrVec.push_back(AttributeWithIndex::get(~0, FnAttrs));
-
-  if (NewRetTy->isVoidTy())
-    Caller->setName("");   // Void type should not have a name.
-
-  const AttrListPtr &NewCallerPAL = AttrListPtr::get(attrVec.begin(),
-                                                     attrVec.end());
-
-  Instruction *NC;
-  if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) {
-    NC = InvokeInst::Create(Callee, II->getNormalDest(), II->getUnwindDest(),
-                            Args.begin(), Args.end(),
-                            Caller->getName(), Caller);
-    cast<InvokeInst>(NC)->setCallingConv(II->getCallingConv());
-    cast<InvokeInst>(NC)->setAttributes(NewCallerPAL);
-  } else {
-    NC = CallInst::Create(Callee, Args.begin(), Args.end(),
-                          Caller->getName(), Caller);
-    CallInst *CI = cast<CallInst>(Caller);
-    if (CI->isTailCall())
-      cast<CallInst>(NC)->setTailCall();
-    cast<CallInst>(NC)->setCallingConv(CI->getCallingConv());
-    cast<CallInst>(NC)->setAttributes(NewCallerPAL);
-  }
-
-  // Insert a cast of the return type as necessary.
-  Value *NV = NC;
-  if (OldRetTy != NV->getType() && !Caller->use_empty()) {
-    if (!NV->getType()->isVoidTy()) {
-      Instruction::CastOps opcode = CastInst::getCastOpcode(NC, false, 
-                                                            OldRetTy, false);
-      NV = NC = CastInst::Create(opcode, NC, OldRetTy, "tmp");
-
-      // If this is an invoke instruction, we should insert it after the first
-      // non-phi, instruction in the normal successor block.
-      if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) {
-        BasicBlock::iterator I = II->getNormalDest()->getFirstNonPHI();
-        InsertNewInstBefore(NC, *I);
-      } else {
-        // Otherwise, it's a call, just insert cast right after the call instr
-        InsertNewInstBefore(NC, *Caller);
-      }
-      Worklist.AddUsersToWorkList(*Caller);
-    } else {
-      NV = UndefValue::get(Caller->getType());
-    }
-  }
-
-
-  if (!Caller->use_empty())
-    Caller->replaceAllUsesWith(NV);
-  
-  EraseInstFromFunction(*Caller);
-  return true;
-}
-
-// transformCallThroughTrampoline - Turn a call to a function created by the
-// init_trampoline intrinsic into a direct call to the underlying function.
-//
-Instruction *InstCombiner::transformCallThroughTrampoline(CallSite CS) {
-  Value *Callee = CS.getCalledValue();
-  const PointerType *PTy = cast<PointerType>(Callee->getType());
-  const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
-  const AttrListPtr &Attrs = CS.getAttributes();
-
-  // If the call already has the 'nest' attribute somewhere then give up -
-  // otherwise 'nest' would occur twice after splicing in the chain.
-  if (Attrs.hasAttrSomewhere(Attribute::Nest))
-    return 0;
-
-  IntrinsicInst *Tramp =
-    cast<IntrinsicInst>(cast<BitCastInst>(Callee)->getOperand(0));
-
-  Function *NestF = cast<Function>(Tramp->getOperand(2)->stripPointerCasts());
-  const PointerType *NestFPTy = cast<PointerType>(NestF->getType());
-  const FunctionType *NestFTy = cast<FunctionType>(NestFPTy->getElementType());
-
-  const AttrListPtr &NestAttrs = NestF->getAttributes();
-  if (!NestAttrs.isEmpty()) {
-    unsigned NestIdx = 1;
-    const Type *NestTy = 0;
-    Attributes NestAttr = Attribute::None;
-
-    // Look for a parameter marked with the 'nest' attribute.
-    for (FunctionType::param_iterator I = NestFTy->param_begin(),
-         E = NestFTy->param_end(); I != E; ++NestIdx, ++I)
-      if (NestAttrs.paramHasAttr(NestIdx, Attribute::Nest)) {
-        // Record the parameter type and any other attributes.
-        NestTy = *I;
-        NestAttr = NestAttrs.getParamAttributes(NestIdx);
-        break;
-      }
-
-    if (NestTy) {
-      Instruction *Caller = CS.getInstruction();
-      std::vector<Value*> NewArgs;
-      NewArgs.reserve(unsigned(CS.arg_end()-CS.arg_begin())+1);
-
-      SmallVector<AttributeWithIndex, 8> NewAttrs;
-      NewAttrs.reserve(Attrs.getNumSlots() + 1);
-
-      // Insert the nest argument into the call argument list, which may
-      // mean appending it.  Likewise for attributes.
-
-      // Add any result attributes.
-      if (Attributes Attr = Attrs.getRetAttributes())
-        NewAttrs.push_back(AttributeWithIndex::get(0, Attr));
-
-      {
-        unsigned Idx = 1;
-        CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end();
-        do {
-          if (Idx == NestIdx) {
-            // Add the chain argument and attributes.
-            Value *NestVal = Tramp->getOperand(3);
-            if (NestVal->getType() != NestTy)
-              NestVal = new BitCastInst(NestVal, NestTy, "nest", Caller);
-            NewArgs.push_back(NestVal);
-            NewAttrs.push_back(AttributeWithIndex::get(NestIdx, NestAttr));
-          }
-
-          if (I == E)
-            break;
-
-          // Add the original argument and attributes.
-          NewArgs.push_back(*I);
-          if (Attributes Attr = Attrs.getParamAttributes(Idx))
-            NewAttrs.push_back
-              (AttributeWithIndex::get(Idx + (Idx >= NestIdx), Attr));
-
-          ++Idx, ++I;
-        } while (1);
-      }
-
-      // Add any function attributes.
-      if (Attributes Attr = Attrs.getFnAttributes())
-        NewAttrs.push_back(AttributeWithIndex::get(~0, Attr));
-
-      // The trampoline may have been bitcast to a bogus type (FTy).
-      // Handle this by synthesizing a new function type, equal to FTy
-      // with the chain parameter inserted.
-
-      std::vector<const Type*> NewTypes;
-      NewTypes.reserve(FTy->getNumParams()+1);
-
-      // Insert the chain's type into the list of parameter types, which may
-      // mean appending it.
-      {
-        unsigned Idx = 1;
-        FunctionType::param_iterator I = FTy->param_begin(),
-          E = FTy->param_end();
-
-        do {
-          if (Idx == NestIdx)
-            // Add the chain's type.
-            NewTypes.push_back(NestTy);
-
-          if (I == E)
-            break;
-
-          // Add the original type.
-          NewTypes.push_back(*I);
-
-          ++Idx, ++I;
-        } while (1);
-      }
-
-      // Replace the trampoline call with a direct call.  Let the generic
-      // code sort out any function type mismatches.
-      FunctionType *NewFTy = FunctionType::get(FTy->getReturnType(), NewTypes, 
-                                                FTy->isVarArg());
-      Constant *NewCallee =
-        NestF->getType() == PointerType::getUnqual(NewFTy) ?
-        NestF : ConstantExpr::getBitCast(NestF, 
-                                         PointerType::getUnqual(NewFTy));
-      const AttrListPtr &NewPAL = AttrListPtr::get(NewAttrs.begin(),
-                                                   NewAttrs.end());
-
-      Instruction *NewCaller;
-      if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) {
-        NewCaller = InvokeInst::Create(NewCallee,
-                                       II->getNormalDest(), II->getUnwindDest(),
-                                       NewArgs.begin(), NewArgs.end(),
-                                       Caller->getName(), Caller);
-        cast<InvokeInst>(NewCaller)->setCallingConv(II->getCallingConv());
-        cast<InvokeInst>(NewCaller)->setAttributes(NewPAL);
-      } else {
-        NewCaller = CallInst::Create(NewCallee, NewArgs.begin(), NewArgs.end(),
-                                     Caller->getName(), Caller);
-        if (cast<CallInst>(Caller)->isTailCall())
-          cast<CallInst>(NewCaller)->setTailCall();
-        cast<CallInst>(NewCaller)->
-          setCallingConv(cast<CallInst>(Caller)->getCallingConv());
-        cast<CallInst>(NewCaller)->setAttributes(NewPAL);
-      }
-      if (!Caller->getType()->isVoidTy())
-        Caller->replaceAllUsesWith(NewCaller);
-      Caller->eraseFromParent();
-      Worklist.Remove(Caller);
-      return 0;
-    }
-  }
-
-  // Replace the trampoline call with a direct call.  Since there is no 'nest'
-  // parameter, there is no need to adjust the argument list.  Let the generic
-  // code sort out any function type mismatches.
-  Constant *NewCallee =
-    NestF->getType() == PTy ? NestF : 
-                              ConstantExpr::getBitCast(NestF, PTy);
-  CS.setCalledFunction(NewCallee);
-  return CS.getInstruction();
-}
-
-/// FoldPHIArgBinOpIntoPHI - If we have something like phi [add (a,b), add(a,c)]
-/// and if a/b/c and the add's all have a single use, turn this into a phi
-/// and a single binop.
-Instruction *InstCombiner::FoldPHIArgBinOpIntoPHI(PHINode &PN) {
-  Instruction *FirstInst = cast<Instruction>(PN.getIncomingValue(0));
-  assert(isa<BinaryOperator>(FirstInst) || isa<CmpInst>(FirstInst));
-  unsigned Opc = FirstInst->getOpcode();
-  Value *LHSVal = FirstInst->getOperand(0);
-  Value *RHSVal = FirstInst->getOperand(1);
-    
-  const Type *LHSType = LHSVal->getType();
-  const Type *RHSType = RHSVal->getType();
-  
-  // Scan to see if all operands are the same opcode, and all have one use.
-  for (unsigned i = 1; i != PN.getNumIncomingValues(); ++i) {
-    Instruction *I = dyn_cast<Instruction>(PN.getIncomingValue(i));
-    if (!I || I->getOpcode() != Opc || !I->hasOneUse() ||
-        // Verify type of the LHS matches so we don't fold cmp's of different
-        // types or GEP's with different index types.
-        I->getOperand(0)->getType() != LHSType ||
-        I->getOperand(1)->getType() != RHSType)
-      return 0;
-
-    // If they are CmpInst instructions, check their predicates
-    if (Opc == Instruction::ICmp || Opc == Instruction::FCmp)
-      if (cast<CmpInst>(I)->getPredicate() !=
-          cast<CmpInst>(FirstInst)->getPredicate())
-        return 0;
-    
-    // Keep track of which operand needs a phi node.
-    if (I->getOperand(0) != LHSVal) LHSVal = 0;
-    if (I->getOperand(1) != RHSVal) RHSVal = 0;
-  }
-
-  // If both LHS and RHS would need a PHI, don't do this transformation,
-  // because it would increase the number of PHIs entering the block,
-  // which leads to higher register pressure. This is especially
-  // bad when the PHIs are in the header of a loop.
-  if (!LHSVal && !RHSVal)
-    return 0;
-  
-  // Otherwise, this is safe to transform!
-  
-  Value *InLHS = FirstInst->getOperand(0);
-  Value *InRHS = FirstInst->getOperand(1);
-  PHINode *NewLHS = 0, *NewRHS = 0;
-  if (LHSVal == 0) {
-    NewLHS = PHINode::Create(LHSType,
-                             FirstInst->getOperand(0)->getName() + ".pn");
-    NewLHS->reserveOperandSpace(PN.getNumOperands()/2);
-    NewLHS->addIncoming(InLHS, PN.getIncomingBlock(0));
-    InsertNewInstBefore(NewLHS, PN);
-    LHSVal = NewLHS;
-  }
-  
-  if (RHSVal == 0) {
-    NewRHS = PHINode::Create(RHSType,
-                             FirstInst->getOperand(1)->getName() + ".pn");
-    NewRHS->reserveOperandSpace(PN.getNumOperands()/2);
-    NewRHS->addIncoming(InRHS, PN.getIncomingBlock(0));
-    InsertNewInstBefore(NewRHS, PN);
-    RHSVal = NewRHS;
-  }
-  
-  // Add all operands to the new PHIs.
-  if (NewLHS || NewRHS) {
-    for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) {
-      Instruction *InInst = cast<Instruction>(PN.getIncomingValue(i));
-      if (NewLHS) {
-        Value *NewInLHS = InInst->getOperand(0);
-        NewLHS->addIncoming(NewInLHS, PN.getIncomingBlock(i));
-      }
-      if (NewRHS) {
-        Value *NewInRHS = InInst->getOperand(1);
-        NewRHS->addIncoming(NewInRHS, PN.getIncomingBlock(i));
-      }
-    }
-  }
-    
-  if (BinaryOperator *BinOp = dyn_cast<BinaryOperator>(FirstInst))
-    return BinaryOperator::Create(BinOp->getOpcode(), LHSVal, RHSVal);
-  CmpInst *CIOp = cast<CmpInst>(FirstInst);
-  return CmpInst::Create(CIOp->getOpcode(), CIOp->getPredicate(),
-                         LHSVal, RHSVal);
-}
-
-Instruction *InstCombiner::FoldPHIArgGEPIntoPHI(PHINode &PN) {
-  GetElementPtrInst *FirstInst =cast<GetElementPtrInst>(PN.getIncomingValue(0));
-  
-  SmallVector<Value*, 16> FixedOperands(FirstInst->op_begin(), 
-                                        FirstInst->op_end());
-  // This is true if all GEP bases are allocas and if all indices into them are
-  // constants.
-  bool AllBasePointersAreAllocas = true;
-
-  // We don't want to replace this phi if the replacement would require
-  // more than one phi, which leads to higher register pressure. This is
-  // especially bad when the PHIs are in the header of a loop.
-  bool NeededPhi = false;
-  
-  // Scan to see if all operands are the same opcode, and all have one use.
-  for (unsigned i = 1; i != PN.getNumIncomingValues(); ++i) {
-    GetElementPtrInst *GEP= dyn_cast<GetElementPtrInst>(PN.getIncomingValue(i));
-    if (!GEP || !GEP->hasOneUse() || GEP->getType() != FirstInst->getType() ||
-      GEP->getNumOperands() != FirstInst->getNumOperands())
-      return 0;
-
-    // Keep track of whether or not all GEPs are of alloca pointers.
-    if (AllBasePointersAreAllocas &&
-        (!isa<AllocaInst>(GEP->getOperand(0)) ||
-         !GEP->hasAllConstantIndices()))
-      AllBasePointersAreAllocas = false;
-    
-    // Compare the operand lists.
-    for (unsigned op = 0, e = FirstInst->getNumOperands(); op != e; ++op) {
-      if (FirstInst->getOperand(op) == GEP->getOperand(op))
-        continue;
-      
-      // Don't merge two GEPs when two operands differ (introducing phi nodes)
-      // if one of the PHIs has a constant for the index.  The index may be
-      // substantially cheaper to compute for the constants, so making it a
-      // variable index could pessimize the path.  This also handles the case
-      // for struct indices, which must always be constant.
-      if (isa<ConstantInt>(FirstInst->getOperand(op)) ||
-          isa<ConstantInt>(GEP->getOperand(op)))
-        return 0;
-      
-      if (FirstInst->getOperand(op)->getType() !=GEP->getOperand(op)->getType())
-        return 0;
-
-      // If we already needed a PHI for an earlier operand, and another operand
-      // also requires a PHI, we'd be introducing more PHIs than we're
-      // eliminating, which increases register pressure on entry to the PHI's
-      // block.
-      if (NeededPhi)
-        return 0;
-
-      FixedOperands[op] = 0;  // Needs a PHI.
-      NeededPhi = true;
-    }
-  }
-  
-  // If all of the base pointers of the PHI'd GEPs are from allocas, don't
-  // bother doing this transformation.  At best, this will just save a bit of
-  // offset calculation, but all the predecessors will have to materialize the
-  // stack address into a register anyway.  We'd actually rather *clone* the
-  // load up into the predecessors so that we have a load of a gep of an alloca,
-  // which can usually all be folded into the load.
-  if (AllBasePointersAreAllocas)
-    return 0;
-  
-  // Otherwise, this is safe to transform.  Insert PHI nodes for each operand
-  // that is variable.
-  SmallVector<PHINode*, 16> OperandPhis(FixedOperands.size());
-  
-  bool HasAnyPHIs = false;
-  for (unsigned i = 0, e = FixedOperands.size(); i != e; ++i) {
-    if (FixedOperands[i]) continue;  // operand doesn't need a phi.
-    Value *FirstOp = FirstInst->getOperand(i);
-    PHINode *NewPN = PHINode::Create(FirstOp->getType(),
-                                     FirstOp->getName()+".pn");
-    InsertNewInstBefore(NewPN, PN);
-    
-    NewPN->reserveOperandSpace(e);
-    NewPN->addIncoming(FirstOp, PN.getIncomingBlock(0));
-    OperandPhis[i] = NewPN;
-    FixedOperands[i] = NewPN;
-    HasAnyPHIs = true;
-  }
-
-  
-  // Add all operands to the new PHIs.
-  if (HasAnyPHIs) {
-    for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) {
-      GetElementPtrInst *InGEP =cast<GetElementPtrInst>(PN.getIncomingValue(i));
-      BasicBlock *InBB = PN.getIncomingBlock(i);
-      
-      for (unsigned op = 0, e = OperandPhis.size(); op != e; ++op)
-        if (PHINode *OpPhi = OperandPhis[op])
-          OpPhi->addIncoming(InGEP->getOperand(op), InBB);
-    }
-  }
-  
-  Value *Base = FixedOperands[0];
-  return cast<GEPOperator>(FirstInst)->isInBounds() ?
-    GetElementPtrInst::CreateInBounds(Base, FixedOperands.begin()+1,
-                                      FixedOperands.end()) :
-    GetElementPtrInst::Create(Base, FixedOperands.begin()+1,
-                              FixedOperands.end());
-}
-
-
-/// isSafeAndProfitableToSinkLoad - Return true if we know that it is safe to
-/// sink the load out of the block that defines it.  This means that it must be
-/// obvious the value of the load is not changed from the point of the load to
-/// the end of the block it is in.
-///
-/// Finally, it is safe, but not profitable, to sink a load targetting a
-/// non-address-taken alloca.  Doing so will cause us to not promote the alloca
-/// to a register.
-static bool isSafeAndProfitableToSinkLoad(LoadInst *L) {
-  BasicBlock::iterator BBI = L, E = L->getParent()->end();
-  
-  for (++BBI; BBI != E; ++BBI)
-    if (BBI->mayWriteToMemory())
-      return false;
-  
-  // Check for non-address taken alloca.  If not address-taken already, it isn't
-  // profitable to do this xform.
-  if (AllocaInst *AI = dyn_cast<AllocaInst>(L->getOperand(0))) {
-    bool isAddressTaken = false;
-    for (Value::use_iterator UI = AI->use_begin(), E = AI->use_end();
-         UI != E; ++UI) {
-      if (isa<LoadInst>(UI)) continue;
-      if (StoreInst *SI = dyn_cast<StoreInst>(*UI)) {
-        // If storing TO the alloca, then the address isn't taken.
-        if (SI->getOperand(1) == AI) continue;
-      }
-      isAddressTaken = true;
-      break;
-    }
-    
-    if (!isAddressTaken && AI->isStaticAlloca())
-      return false;
-  }
-  
-  // If this load is a load from a GEP with a constant offset from an alloca,
-  // then we don't want to sink it.  In its present form, it will be
-  // load [constant stack offset].  Sinking it will cause us to have to
-  // materialize the stack addresses in each predecessor in a register only to
-  // do a shared load from register in the successor.
-  if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(L->getOperand(0)))
-    if (AllocaInst *AI = dyn_cast<AllocaInst>(GEP->getOperand(0)))
-      if (AI->isStaticAlloca() && GEP->hasAllConstantIndices())
-        return false;
-  
-  return true;
-}
-
-Instruction *InstCombiner::FoldPHIArgLoadIntoPHI(PHINode &PN) {
-  LoadInst *FirstLI = cast<LoadInst>(PN.getIncomingValue(0));
-  
-  // When processing loads, we need to propagate two bits of information to the
-  // sunk load: whether it is volatile, and what its alignment is.  We currently
-  // don't sink loads when some have their alignment specified and some don't.
-  // visitLoadInst will propagate an alignment onto the load when TD is around,
-  // and if TD isn't around, we can't handle the mixed case.
-  bool isVolatile = FirstLI->isVolatile();
-  unsigned LoadAlignment = FirstLI->getAlignment();
-  
-  // We can't sink the load if the loaded value could be modified between the
-  // load and the PHI.
-  if (FirstLI->getParent() != PN.getIncomingBlock(0) ||
-      !isSafeAndProfitableToSinkLoad(FirstLI))
-    return 0;
-  
-  // If the PHI is of volatile loads and the load block has multiple
-  // successors, sinking it would remove a load of the volatile value from
-  // the path through the other successor.
-  if (isVolatile && 
-      FirstLI->getParent()->getTerminator()->getNumSuccessors() != 1)
-    return 0;
-  
-  // Check to see if all arguments are the same operation.
-  for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) {
-    LoadInst *LI = dyn_cast<LoadInst>(PN.getIncomingValue(i));
-    if (!LI || !LI->hasOneUse())
-      return 0;
-    
-    // We can't sink the load if the loaded value could be modified between 
-    // the load and the PHI.
-    if (LI->isVolatile() != isVolatile ||
-        LI->getParent() != PN.getIncomingBlock(i) ||
-        !isSafeAndProfitableToSinkLoad(LI))
-      return 0;
-      
-    // If some of the loads have an alignment specified but not all of them,
-    // we can't do the transformation.
-    if ((LoadAlignment != 0) != (LI->getAlignment() != 0))
-      return 0;
-    
-    LoadAlignment = std::min(LoadAlignment, LI->getAlignment());
-    
-    // If the PHI is of volatile loads and the load block has multiple
-    // successors, sinking it would remove a load of the volatile value from
-    // the path through the other successor.
-    if (isVolatile &&
-        LI->getParent()->getTerminator()->getNumSuccessors() != 1)
-      return 0;
-  }
-  
-  // Okay, they are all the same operation.  Create a new PHI node of the
-  // correct type, and PHI together all of the LHS's of the instructions.
-  PHINode *NewPN = PHINode::Create(FirstLI->getOperand(0)->getType(),
-                                   PN.getName()+".in");
-  NewPN->reserveOperandSpace(PN.getNumOperands()/2);
-  
-  Value *InVal = FirstLI->getOperand(0);
-  NewPN->addIncoming(InVal, PN.getIncomingBlock(0));
-  
-  // Add all operands to the new PHI.
-  for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) {
-    Value *NewInVal = cast<LoadInst>(PN.getIncomingValue(i))->getOperand(0);
-    if (NewInVal != InVal)
-      InVal = 0;
-    NewPN->addIncoming(NewInVal, PN.getIncomingBlock(i));
-  }
-  
-  Value *PhiVal;
-  if (InVal) {
-    // The new PHI unions all of the same values together.  This is really
-    // common, so we handle it intelligently here for compile-time speed.
-    PhiVal = InVal;
-    delete NewPN;
-  } else {
-    InsertNewInstBefore(NewPN, PN);
-    PhiVal = NewPN;
-  }
-  
-  // If this was a volatile load that we are merging, make sure to loop through
-  // and mark all the input loads as non-volatile.  If we don't do this, we will
-  // insert a new volatile load and the old ones will not be deletable.
-  if (isVolatile)
-    for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i)
-      cast<LoadInst>(PN.getIncomingValue(i))->setVolatile(false);
-  
-  return new LoadInst(PhiVal, "", isVolatile, LoadAlignment);
-}
-
-
-
-/// FoldPHIArgOpIntoPHI - If all operands to a PHI node are the same "unary"
-/// operator and they all are only used by the PHI, PHI together their
-/// inputs, and do the operation once, to the result of the PHI.
-Instruction *InstCombiner::FoldPHIArgOpIntoPHI(PHINode &PN) {
-  Instruction *FirstInst = cast<Instruction>(PN.getIncomingValue(0));
-
-  if (isa<GetElementPtrInst>(FirstInst))
-    return FoldPHIArgGEPIntoPHI(PN);
-  if (isa<LoadInst>(FirstInst))
-    return FoldPHIArgLoadIntoPHI(PN);
-  
-  // Scan the instruction, looking for input operations that can be folded away.
-  // If all input operands to the phi are the same instruction (e.g. a cast from
-  // the same type or "+42") we can pull the operation through the PHI, reducing
-  // code size and simplifying code.
-  Constant *ConstantOp = 0;
-  const Type *CastSrcTy = 0;
-  
-  if (isa<CastInst>(FirstInst)) {
-    CastSrcTy = FirstInst->getOperand(0)->getType();
-
-    // Be careful about transforming integer PHIs.  We don't want to pessimize
-    // the code by turning an i32 into an i1293.
-    if (isa<IntegerType>(PN.getType()) && isa<IntegerType>(CastSrcTy)) {
-      if (!ShouldChangeType(PN.getType(), CastSrcTy, TD))
-        return 0;
-    }
-  } else if (isa<BinaryOperator>(FirstInst) || isa<CmpInst>(FirstInst)) {
-    // Can fold binop, compare or shift here if the RHS is a constant, 
-    // otherwise call FoldPHIArgBinOpIntoPHI.
-    ConstantOp = dyn_cast<Constant>(FirstInst->getOperand(1));
-    if (ConstantOp == 0)
-      return FoldPHIArgBinOpIntoPHI(PN);
-  } else {
-    return 0;  // Cannot fold this operation.
-  }
-
-  // Check to see if all arguments are the same operation.
-  for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) {
-    Instruction *I = dyn_cast<Instruction>(PN.getIncomingValue(i));
-    if (I == 0 || !I->hasOneUse() || !I->isSameOperationAs(FirstInst))
-      return 0;
-    if (CastSrcTy) {
-      if (I->getOperand(0)->getType() != CastSrcTy)
-        return 0;  // Cast operation must match.
-    } else if (I->getOperand(1) != ConstantOp) {
-      return 0;
-    }
-  }
-
-  // Okay, they are all the same operation.  Create a new PHI node of the
-  // correct type, and PHI together all of the LHS's of the instructions.
-  PHINode *NewPN = PHINode::Create(FirstInst->getOperand(0)->getType(),
-                                   PN.getName()+".in");
-  NewPN->reserveOperandSpace(PN.getNumOperands()/2);
-
-  Value *InVal = FirstInst->getOperand(0);
-  NewPN->addIncoming(InVal, PN.getIncomingBlock(0));
-
-  // Add all operands to the new PHI.
-  for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) {
-    Value *NewInVal = cast<Instruction>(PN.getIncomingValue(i))->getOperand(0);
-    if (NewInVal != InVal)
-      InVal = 0;
-    NewPN->addIncoming(NewInVal, PN.getIncomingBlock(i));
-  }
-
-  Value *PhiVal;
-  if (InVal) {
-    // The new PHI unions all of the same values together.  This is really
-    // common, so we handle it intelligently here for compile-time speed.
-    PhiVal = InVal;
-    delete NewPN;
-  } else {
-    InsertNewInstBefore(NewPN, PN);
-    PhiVal = NewPN;
-  }
-
-  // Insert and return the new operation.
-  if (CastInst *FirstCI = dyn_cast<CastInst>(FirstInst))
-    return CastInst::Create(FirstCI->getOpcode(), PhiVal, PN.getType());
-  
-  if (BinaryOperator *BinOp = dyn_cast<BinaryOperator>(FirstInst))
-    return BinaryOperator::Create(BinOp->getOpcode(), PhiVal, ConstantOp);
-  
-  CmpInst *CIOp = cast<CmpInst>(FirstInst);
-  return CmpInst::Create(CIOp->getOpcode(), CIOp->getPredicate(),
-                         PhiVal, ConstantOp);
-}
-
-/// DeadPHICycle - Return true if this PHI node is only used by a PHI node cycle
-/// that is dead.
-static bool DeadPHICycle(PHINode *PN,
-                         SmallPtrSet<PHINode*, 16> &PotentiallyDeadPHIs) {
-  if (PN->use_empty()) return true;
-  if (!PN->hasOneUse()) return false;
-
-  // Remember this node, and if we find the cycle, return.
-  if (!PotentiallyDeadPHIs.insert(PN))
-    return true;
-  
-  // Don't scan crazily complex things.
-  if (PotentiallyDeadPHIs.size() == 16)
-    return false;
-
-  if (PHINode *PU = dyn_cast<PHINode>(PN->use_back()))
-    return DeadPHICycle(PU, PotentiallyDeadPHIs);
-
-  return false;
-}
-
-/// PHIsEqualValue - Return true if this phi node is always equal to
-/// NonPhiInVal.  This happens with mutually cyclic phi nodes like:
-///   z = some value; x = phi (y, z); y = phi (x, z)
-static bool PHIsEqualValue(PHINode *PN, Value *NonPhiInVal, 
-                           SmallPtrSet<PHINode*, 16> &ValueEqualPHIs) {
-  // See if we already saw this PHI node.
-  if (!ValueEqualPHIs.insert(PN))
-    return true;
-  
-  // Don't scan crazily complex things.
-  if (ValueEqualPHIs.size() == 16)
-    return false;
- 
-  // Scan the operands to see if they are either phi nodes or are equal to
-  // the value.
-  for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
-    Value *Op = PN->getIncomingValue(i);
-    if (PHINode *OpPN = dyn_cast<PHINode>(Op)) {
-      if (!PHIsEqualValue(OpPN, NonPhiInVal, ValueEqualPHIs))
-        return false;
-    } else if (Op != NonPhiInVal)
-      return false;
-  }
-  
-  return true;
-}
-
-
-namespace {
-struct PHIUsageRecord {
-  unsigned PHIId;     // The ID # of the PHI (something determinstic to sort on)
-  unsigned Shift;     // The amount shifted.
-  Instruction *Inst;  // The trunc instruction.
-  
-  PHIUsageRecord(unsigned pn, unsigned Sh, Instruction *User)
-    : PHIId(pn), Shift(Sh), Inst(User) {}
-  
-  bool operator<(const PHIUsageRecord &RHS) const {
-    if (PHIId < RHS.PHIId) return true;
-    if (PHIId > RHS.PHIId) return false;
-    if (Shift < RHS.Shift) return true;
-    if (Shift > RHS.Shift) return false;
-    return Inst->getType()->getPrimitiveSizeInBits() <
-           RHS.Inst->getType()->getPrimitiveSizeInBits();
-  }
-};
-  
-struct LoweredPHIRecord {
-  PHINode *PN;        // The PHI that was lowered.
-  unsigned Shift;     // The amount shifted.
-  unsigned Width;     // The width extracted.
-  
-  LoweredPHIRecord(PHINode *pn, unsigned Sh, const Type *Ty)
-    : PN(pn), Shift(Sh), Width(Ty->getPrimitiveSizeInBits()) {}
-  
-  // Ctor form used by DenseMap.
-  LoweredPHIRecord(PHINode *pn, unsigned Sh)
-    : PN(pn), Shift(Sh), Width(0) {}
-};
-}
-
-namespace llvm {
-  template<>
-  struct DenseMapInfo<LoweredPHIRecord> {
-    static inline LoweredPHIRecord getEmptyKey() {
-      return LoweredPHIRecord(0, 0);
-    }
-    static inline LoweredPHIRecord getTombstoneKey() {
-      return LoweredPHIRecord(0, 1);
-    }
-    static unsigned getHashValue(const LoweredPHIRecord &Val) {
-      return DenseMapInfo<PHINode*>::getHashValue(Val.PN) ^ (Val.Shift>>3) ^
-             (Val.Width>>3);
-    }
-    static bool isEqual(const LoweredPHIRecord &LHS,
-                        const LoweredPHIRecord &RHS) {
-      return LHS.PN == RHS.PN && LHS.Shift == RHS.Shift &&
-             LHS.Width == RHS.Width;
-    }
-  };
-  template <>
-  struct isPodLike<LoweredPHIRecord> { static const bool value = true; };
-}
-
-
-/// SliceUpIllegalIntegerPHI - This is an integer PHI and we know that it has an
-/// illegal type: see if it is only used by trunc or trunc(lshr) operations.  If
-/// so, we split the PHI into the various pieces being extracted.  This sort of
-/// thing is introduced when SROA promotes an aggregate to large integer values.
-///
-/// TODO: The user of the trunc may be an bitcast to float/double/vector or an
-/// inttoptr.  We should produce new PHIs in the right type.
-///
-Instruction *InstCombiner::SliceUpIllegalIntegerPHI(PHINode &FirstPhi) {
-  // PHIUsers - Keep track of all of the truncated values extracted from a set
-  // of PHIs, along with their offset.  These are the things we want to rewrite.
-  SmallVector<PHIUsageRecord, 16> PHIUsers;
-  
-  // PHIs are often mutually cyclic, so we keep track of a whole set of PHI
-  // nodes which are extracted from. PHIsToSlice is a set we use to avoid
-  // revisiting PHIs, PHIsInspected is a ordered list of PHIs that we need to
-  // check the uses of (to ensure they are all extracts).
-  SmallVector<PHINode*, 8> PHIsToSlice;
-  SmallPtrSet<PHINode*, 8> PHIsInspected;
-  
-  PHIsToSlice.push_back(&FirstPhi);
-  PHIsInspected.insert(&FirstPhi);
-  
-  for (unsigned PHIId = 0; PHIId != PHIsToSlice.size(); ++PHIId) {
-    PHINode *PN = PHIsToSlice[PHIId];
-    
-    // Scan the input list of the PHI.  If any input is an invoke, and if the
-    // input is defined in the predecessor, then we won't be split the critical
-    // edge which is required to insert a truncate.  Because of this, we have to
-    // bail out.
-    for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
-      InvokeInst *II = dyn_cast<InvokeInst>(PN->getIncomingValue(i));
-      if (II == 0) continue;
-      if (II->getParent() != PN->getIncomingBlock(i))
-        continue;
-     
-      // If we have a phi, and if it's directly in the predecessor, then we have
-      // a critical edge where we need to put the truncate.  Since we can't
-      // split the edge in instcombine, we have to bail out.
-      return 0;
-    }
-      
-    
-    for (Value::use_iterator UI = PN->use_begin(), E = PN->use_end();
-         UI != E; ++UI) {
-      Instruction *User = cast<Instruction>(*UI);
-      
-      // If the user is a PHI, inspect its uses recursively.
-      if (PHINode *UserPN = dyn_cast<PHINode>(User)) {
-        if (PHIsInspected.insert(UserPN))
-          PHIsToSlice.push_back(UserPN);
-        continue;
-      }
-      
-      // Truncates are always ok.
-      if (isa<TruncInst>(User)) {
-        PHIUsers.push_back(PHIUsageRecord(PHIId, 0, User));
-        continue;
-      }
-      
-      // Otherwise it must be a lshr which can only be used by one trunc.
-      if (User->getOpcode() != Instruction::LShr ||
-          !User->hasOneUse() || !isa<TruncInst>(User->use_back()) ||
-          !isa<ConstantInt>(User->getOperand(1)))
-        return 0;
-      
-      unsigned Shift = cast<ConstantInt>(User->getOperand(1))->getZExtValue();
-      PHIUsers.push_back(PHIUsageRecord(PHIId, Shift, User->use_back()));
-    }
-  }
-  
-  // If we have no users, they must be all self uses, just nuke the PHI.
-  if (PHIUsers.empty())
-    return ReplaceInstUsesWith(FirstPhi, UndefValue::get(FirstPhi.getType()));
-  
-  // If this phi node is transformable, create new PHIs for all the pieces
-  // extracted out of it.  First, sort the users by their offset and size.
-  array_pod_sort(PHIUsers.begin(), PHIUsers.end());
-  
-  DEBUG(errs() << "SLICING UP PHI: " << FirstPhi << '\n';
-            for (unsigned i = 1, e = PHIsToSlice.size(); i != e; ++i)
-              errs() << "AND USER PHI #" << i << ": " << *PHIsToSlice[i] <<'\n';
-        );
-  
-  // PredValues - This is a temporary used when rewriting PHI nodes.  It is
-  // hoisted out here to avoid construction/destruction thrashing.
-  DenseMap<BasicBlock*, Value*> PredValues;
-  
-  // ExtractedVals - Each new PHI we introduce is saved here so we don't
-  // introduce redundant PHIs.
-  DenseMap<LoweredPHIRecord, PHINode*> ExtractedVals;
-  
-  for (unsigned UserI = 0, UserE = PHIUsers.size(); UserI != UserE; ++UserI) {
-    unsigned PHIId = PHIUsers[UserI].PHIId;
-    PHINode *PN = PHIsToSlice[PHIId];
-    unsigned Offset = PHIUsers[UserI].Shift;
-    const Type *Ty = PHIUsers[UserI].Inst->getType();
-    
-    PHINode *EltPHI;
-    
-    // If we've already lowered a user like this, reuse the previously lowered
-    // value.
-    if ((EltPHI = ExtractedVals[LoweredPHIRecord(PN, Offset, Ty)]) == 0) {
-      
-      // Otherwise, Create the new PHI node for this user.
-      EltPHI = PHINode::Create(Ty, PN->getName()+".off"+Twine(Offset), PN);
-      assert(EltPHI->getType() != PN->getType() &&
-             "Truncate didn't shrink phi?");
-    
-      for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
-        BasicBlock *Pred = PN->getIncomingBlock(i);
-        Value *&PredVal = PredValues[Pred];
-        
-        // If we already have a value for this predecessor, reuse it.
-        if (PredVal) {
-          EltPHI->addIncoming(PredVal, Pred);
-          continue;
-        }
-
-        // Handle the PHI self-reuse case.
-        Value *InVal = PN->getIncomingValue(i);
-        if (InVal == PN) {
-          PredVal = EltPHI;
-          EltPHI->addIncoming(PredVal, Pred);
-          continue;
-        }
-        
-        if (PHINode *InPHI = dyn_cast<PHINode>(PN)) {
-          // If the incoming value was a PHI, and if it was one of the PHIs we
-          // already rewrote it, just use the lowered value.
-          if (Value *Res = ExtractedVals[LoweredPHIRecord(InPHI, Offset, Ty)]) {
-            PredVal = Res;
-            EltPHI->addIncoming(PredVal, Pred);
-            continue;
-          }
-        }
-        
-        // Otherwise, do an extract in the predecessor.
-        Builder->SetInsertPoint(Pred, Pred->getTerminator());
-        Value *Res = InVal;
-        if (Offset)
-          Res = Builder->CreateLShr(Res, ConstantInt::get(InVal->getType(),
-                                                          Offset), "extract");
-        Res = Builder->CreateTrunc(Res, Ty, "extract.t");
-        PredVal = Res;
-        EltPHI->addIncoming(Res, Pred);
-        
-        // If the incoming value was a PHI, and if it was one of the PHIs we are
-        // rewriting, we will ultimately delete the code we inserted.  This
-        // means we need to revisit that PHI to make sure we extract out the
-        // needed piece.
-        if (PHINode *OldInVal = dyn_cast<PHINode>(PN->getIncomingValue(i)))
-          if (PHIsInspected.count(OldInVal)) {
-            unsigned RefPHIId = std::find(PHIsToSlice.begin(),PHIsToSlice.end(),
-                                          OldInVal)-PHIsToSlice.begin();
-            PHIUsers.push_back(PHIUsageRecord(RefPHIId, Offset, 
-                                              cast<Instruction>(Res)));
-            ++UserE;
-          }
-      }
-      PredValues.clear();
-      
-      DEBUG(errs() << "  Made element PHI for offset " << Offset << ": "
-                   << *EltPHI << '\n');
-      ExtractedVals[LoweredPHIRecord(PN, Offset, Ty)] = EltPHI;
-    }
-    
-    // Replace the use of this piece with the PHI node.
-    ReplaceInstUsesWith(*PHIUsers[UserI].Inst, EltPHI);
-  }
-  
-  // Replace all the remaining uses of the PHI nodes (self uses and the lshrs)
-  // with undefs.
-  Value *Undef = UndefValue::get(FirstPhi.getType());
-  for (unsigned i = 1, e = PHIsToSlice.size(); i != e; ++i)
-    ReplaceInstUsesWith(*PHIsToSlice[i], Undef);
-  return ReplaceInstUsesWith(FirstPhi, Undef);
-}
-
-// PHINode simplification
-//
-Instruction *InstCombiner::visitPHINode(PHINode &PN) {
-  // If LCSSA is around, don't mess with Phi nodes
-  if (MustPreserveLCSSA) return 0;
-  
-  if (Value *V = PN.hasConstantValue())
-    return ReplaceInstUsesWith(PN, V);
-
-  // If all PHI operands are the same operation, pull them through the PHI,
-  // reducing code size.
-  if (isa<Instruction>(PN.getIncomingValue(0)) &&
-      isa<Instruction>(PN.getIncomingValue(1)) &&
-      cast<Instruction>(PN.getIncomingValue(0))->getOpcode() ==
-      cast<Instruction>(PN.getIncomingValue(1))->getOpcode() &&
-      // FIXME: The hasOneUse check will fail for PHIs that use the value more
-      // than themselves more than once.
-      PN.getIncomingValue(0)->hasOneUse())
-    if (Instruction *Result = FoldPHIArgOpIntoPHI(PN))
-      return Result;
-
-  // If this is a trivial cycle in the PHI node graph, remove it.  Basically, if
-  // this PHI only has a single use (a PHI), and if that PHI only has one use (a
-  // PHI)... break the cycle.
-  if (PN.hasOneUse()) {
-    Instruction *PHIUser = cast<Instruction>(PN.use_back());
-    if (PHINode *PU = dyn_cast<PHINode>(PHIUser)) {
-      SmallPtrSet<PHINode*, 16> PotentiallyDeadPHIs;
-      PotentiallyDeadPHIs.insert(&PN);
-      if (DeadPHICycle(PU, PotentiallyDeadPHIs))
-        return ReplaceInstUsesWith(PN, UndefValue::get(PN.getType()));
-    }
-   
-    // If this phi has a single use, and if that use just computes a value for
-    // the next iteration of a loop, delete the phi.  This occurs with unused
-    // induction variables, e.g. "for (int j = 0; ; ++j);".  Detecting this
-    // common case here is good because the only other things that catch this
-    // are induction variable analysis (sometimes) and ADCE, which is only run
-    // late.
-    if (PHIUser->hasOneUse() &&
-        (isa<BinaryOperator>(PHIUser) || isa<GetElementPtrInst>(PHIUser)) &&
-        PHIUser->use_back() == &PN) {
-      return ReplaceInstUsesWith(PN, UndefValue::get(PN.getType()));
-    }
-  }
-
-  // We sometimes end up with phi cycles that non-obviously end up being the
-  // same value, for example:
-  //   z = some value; x = phi (y, z); y = phi (x, z)
-  // where the phi nodes don't necessarily need to be in the same block.  Do a
-  // quick check to see if the PHI node only contains a single non-phi value, if
-  // so, scan to see if the phi cycle is actually equal to that value.
-  {
-    unsigned InValNo = 0, NumOperandVals = PN.getNumIncomingValues();
-    // Scan for the first non-phi operand.
-    while (InValNo != NumOperandVals && 
-           isa<PHINode>(PN.getIncomingValue(InValNo)))
-      ++InValNo;
-
-    if (InValNo != NumOperandVals) {
-      Value *NonPhiInVal = PN.getOperand(InValNo);
-      
-      // Scan the rest of the operands to see if there are any conflicts, if so
-      // there is no need to recursively scan other phis.
-      for (++InValNo; InValNo != NumOperandVals; ++InValNo) {
-        Value *OpVal = PN.getIncomingValue(InValNo);
-        if (OpVal != NonPhiInVal && !isa<PHINode>(OpVal))
-          break;
-      }
-      
-      // If we scanned over all operands, then we have one unique value plus
-      // phi values.  Scan PHI nodes to see if they all merge in each other or
-      // the value.
-      if (InValNo == NumOperandVals) {
-        SmallPtrSet<PHINode*, 16> ValueEqualPHIs;
-        if (PHIsEqualValue(&PN, NonPhiInVal, ValueEqualPHIs))
-          return ReplaceInstUsesWith(PN, NonPhiInVal);
-      }
-    }
-  }
-
-  // If there are multiple PHIs, sort their operands so that they all list
-  // the blocks in the same order. This will help identical PHIs be eliminated
-  // by other passes. Other passes shouldn't depend on this for correctness
-  // however.
-  PHINode *FirstPN = cast<PHINode>(PN.getParent()->begin());
-  if (&PN != FirstPN)
-    for (unsigned i = 0, e = FirstPN->getNumIncomingValues(); i != e; ++i) {
-      BasicBlock *BBA = PN.getIncomingBlock(i);
-      BasicBlock *BBB = FirstPN->getIncomingBlock(i);
-      if (BBA != BBB) {
-        Value *VA = PN.getIncomingValue(i);
-        unsigned j = PN.getBasicBlockIndex(BBB);
-        Value *VB = PN.getIncomingValue(j);
-        PN.setIncomingBlock(i, BBB);
-        PN.setIncomingValue(i, VB);
-        PN.setIncomingBlock(j, BBA);
-        PN.setIncomingValue(j, VA);
-        // NOTE: Instcombine normally would want us to "return &PN" if we
-        // modified any of the operands of an instruction.  However, since we
-        // aren't adding or removing uses (just rearranging them) we don't do
-        // this in this case.
-      }
-    }
-
-  // If this is an integer PHI and we know that it has an illegal type, see if
-  // it is only used by trunc or trunc(lshr) operations.  If so, we split the
-  // PHI into the various pieces being extracted.  This sort of thing is
-  // introduced when SROA promotes an aggregate to a single large integer type.
-  if (isa<IntegerType>(PN.getType()) && TD &&
-      !TD->isLegalInteger(PN.getType()->getPrimitiveSizeInBits()))
-    if (Instruction *Res = SliceUpIllegalIntegerPHI(PN))
-      return Res;
-  
-  return 0;
-}
-
-Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
-  SmallVector<Value*, 8> Ops(GEP.op_begin(), GEP.op_end());
-
-  if (Value *V = SimplifyGEPInst(&Ops[0], Ops.size(), TD))
-    return ReplaceInstUsesWith(GEP, V);
-
-  Value *PtrOp = GEP.getOperand(0);
-
-  if (isa<UndefValue>(GEP.getOperand(0)))
-    return ReplaceInstUsesWith(GEP, UndefValue::get(GEP.getType()));
-
-  // Eliminate unneeded casts for indices.
-  if (TD) {
-    bool MadeChange = false;
-    unsigned PtrSize = TD->getPointerSizeInBits();
-    
-    gep_type_iterator GTI = gep_type_begin(GEP);
-    for (User::op_iterator I = GEP.op_begin() + 1, E = GEP.op_end();
-         I != E; ++I, ++GTI) {
-      if (!isa<SequentialType>(*GTI)) continue;
-      
-      // If we are using a wider index than needed for this platform, shrink it
-      // to what we need.  If narrower, sign-extend it to what we need.  This
-      // explicit cast can make subsequent optimizations more obvious.
-      unsigned OpBits = cast<IntegerType>((*I)->getType())->getBitWidth();
-      if (OpBits == PtrSize)
-        continue;
-      
-      *I = Builder->CreateIntCast(*I, TD->getIntPtrType(GEP.getContext()),true);
-      MadeChange = true;
-    }
-    if (MadeChange) return &GEP;
-  }
-
-  // Combine Indices - If the source pointer to this getelementptr instruction
-  // is a getelementptr instruction, combine the indices of the two
-  // getelementptr instructions into a single instruction.
-  //
-  if (GEPOperator *Src = dyn_cast<GEPOperator>(PtrOp)) {
-    // Note that if our source is a gep chain itself that we wait for that
-    // chain to be resolved before we perform this transformation.  This
-    // avoids us creating a TON of code in some cases.
-    //
-    if (GetElementPtrInst *SrcGEP =
-          dyn_cast<GetElementPtrInst>(Src->getOperand(0)))
-      if (SrcGEP->getNumOperands() == 2)
-        return 0;   // Wait until our source is folded to completion.
-
-    SmallVector<Value*, 8> Indices;
-
-    // Find out whether the last index in the source GEP is a sequential idx.
-    bool EndsWithSequential = false;
-    for (gep_type_iterator I = gep_type_begin(*Src), E = gep_type_end(*Src);
-         I != E; ++I)
-      EndsWithSequential = !isa<StructType>(*I);
-
-    // Can we combine the two pointer arithmetics offsets?
-    if (EndsWithSequential) {
-      // Replace: gep (gep %P, long B), long A, ...
-      // With:    T = long A+B; gep %P, T, ...
-      //
-      Value *Sum;
-      Value *SO1 = Src->getOperand(Src->getNumOperands()-1);
-      Value *GO1 = GEP.getOperand(1);
-      if (SO1 == Constant::getNullValue(SO1->getType())) {
-        Sum = GO1;
-      } else if (GO1 == Constant::getNullValue(GO1->getType())) {
-        Sum = SO1;
-      } else {
-        // If they aren't the same type, then the input hasn't been processed
-        // by the loop above yet (which canonicalizes sequential index types to
-        // intptr_t).  Just avoid transforming this until the input has been
-        // normalized.
-        if (SO1->getType() != GO1->getType())
-          return 0;
-        Sum = Builder->CreateAdd(SO1, GO1, PtrOp->getName()+".sum");
-      }
-
-      // Update the GEP in place if possible.
-      if (Src->getNumOperands() == 2) {
-        GEP.setOperand(0, Src->getOperand(0));
-        GEP.setOperand(1, Sum);
-        return &GEP;
-      }
-      Indices.append(Src->op_begin()+1, Src->op_end()-1);
-      Indices.push_back(Sum);
-      Indices.append(GEP.op_begin()+2, GEP.op_end());
-    } else if (isa<Constant>(*GEP.idx_begin()) &&
-               cast<Constant>(*GEP.idx_begin())->isNullValue() &&
-               Src->getNumOperands() != 1) {
-      // Otherwise we can do the fold if the first index of the GEP is a zero
-      Indices.append(Src->op_begin()+1, Src->op_end());
-      Indices.append(GEP.idx_begin()+1, GEP.idx_end());
-    }
-
-    if (!Indices.empty())
-      return (cast<GEPOperator>(&GEP)->isInBounds() &&
-              Src->isInBounds()) ?
-        GetElementPtrInst::CreateInBounds(Src->getOperand(0), Indices.begin(),
-                                          Indices.end(), GEP.getName()) :
-        GetElementPtrInst::Create(Src->getOperand(0), Indices.begin(),
-                                  Indices.end(), GEP.getName());
-  }
-  
-  // Handle gep(bitcast x) and gep(gep x, 0, 0, 0).
-  if (Value *X = getBitCastOperand(PtrOp)) {
-    assert(isa<PointerType>(X->getType()) && "Must be cast from pointer");
-
-    // If the input bitcast is actually "bitcast(bitcast(x))", then we don't 
-    // want to change the gep until the bitcasts are eliminated.
-    if (getBitCastOperand(X)) {
-      Worklist.AddValue(PtrOp);
-      return 0;
-    }
-    
-    bool HasZeroPointerIndex = false;
-    if (ConstantInt *C = dyn_cast<ConstantInt>(GEP.getOperand(1)))
-      HasZeroPointerIndex = C->isZero();
-    
-    // Transform: GEP (bitcast [10 x i8]* X to [0 x i8]*), i32 0, ...
-    // into     : GEP [10 x i8]* X, i32 0, ...
-    //
-    // Likewise, transform: GEP (bitcast i8* X to [0 x i8]*), i32 0, ...
-    //           into     : GEP i8* X, ...
-    // 
-    // This occurs when the program declares an array extern like "int X[];"
-    if (HasZeroPointerIndex) {
-      const PointerType *CPTy = cast<PointerType>(PtrOp->getType());
-      const PointerType *XTy = cast<PointerType>(X->getType());
-      if (const ArrayType *CATy =
-          dyn_cast<ArrayType>(CPTy->getElementType())) {
-        // GEP (bitcast i8* X to [0 x i8]*), i32 0, ... ?
-        if (CATy->getElementType() == XTy->getElementType()) {
-          // -> GEP i8* X, ...
-          SmallVector<Value*, 8> Indices(GEP.idx_begin()+1, GEP.idx_end());
-          return cast<GEPOperator>(&GEP)->isInBounds() ?
-            GetElementPtrInst::CreateInBounds(X, Indices.begin(), Indices.end(),
-                                              GEP.getName()) :
-            GetElementPtrInst::Create(X, Indices.begin(), Indices.end(),
-                                      GEP.getName());
-        }
-        
-        if (const ArrayType *XATy = dyn_cast<ArrayType>(XTy->getElementType())){
-          // GEP (bitcast [10 x i8]* X to [0 x i8]*), i32 0, ... ?
-          if (CATy->getElementType() == XATy->getElementType()) {
-            // -> GEP [10 x i8]* X, i32 0, ...
-            // At this point, we know that the cast source type is a pointer
-            // to an array of the same type as the destination pointer
-            // array.  Because the array type is never stepped over (there
-            // is a leading zero) we can fold the cast into this GEP.
-            GEP.setOperand(0, X);
-            return &GEP;
-          }
-        }
-      }
-    } else if (GEP.getNumOperands() == 2) {
-      // Transform things like:
-      // %t = getelementptr i32* bitcast ([2 x i32]* %str to i32*), i32 %V
-      // into:  %t1 = getelementptr [2 x i32]* %str, i32 0, i32 %V; bitcast
-      const Type *SrcElTy = cast<PointerType>(X->getType())->getElementType();
-      const Type *ResElTy=cast<PointerType>(PtrOp->getType())->getElementType();
-      if (TD && isa<ArrayType>(SrcElTy) &&
-          TD->getTypeAllocSize(cast<ArrayType>(SrcElTy)->getElementType()) ==
-          TD->getTypeAllocSize(ResElTy)) {
-        Value *Idx[2];
-        Idx[0] = Constant::getNullValue(Type::getInt32Ty(*Context));
-        Idx[1] = GEP.getOperand(1);
-        Value *NewGEP = cast<GEPOperator>(&GEP)->isInBounds() ?
-          Builder->CreateInBoundsGEP(X, Idx, Idx + 2, GEP.getName()) :
-          Builder->CreateGEP(X, Idx, Idx + 2, GEP.getName());
-        // V and GEP are both pointer types --> BitCast
-        return new BitCastInst(NewGEP, GEP.getType());
-      }
-      
-      // Transform things like:
-      // getelementptr i8* bitcast ([100 x double]* X to i8*), i32 %tmp
-      //   (where tmp = 8*tmp2) into:
-      // getelementptr [100 x double]* %arr, i32 0, i32 %tmp2; bitcast
-      
-      if (TD && isa<ArrayType>(SrcElTy) && ResElTy == Type::getInt8Ty(*Context)) {
-        uint64_t ArrayEltSize =
-            TD->getTypeAllocSize(cast<ArrayType>(SrcElTy)->getElementType());
-        
-        // Check to see if "tmp" is a scale by a multiple of ArrayEltSize.  We
-        // allow either a mul, shift, or constant here.
-        Value *NewIdx = 0;
-        ConstantInt *Scale = 0;
-        if (ArrayEltSize == 1) {
-          NewIdx = GEP.getOperand(1);
-          Scale = ConstantInt::get(cast<IntegerType>(NewIdx->getType()), 1);
-        } else if (ConstantInt *CI = dyn_cast<ConstantInt>(GEP.getOperand(1))) {
-          NewIdx = ConstantInt::get(CI->getType(), 1);
-          Scale = CI;
-        } else if (Instruction *Inst =dyn_cast<Instruction>(GEP.getOperand(1))){
-          if (Inst->getOpcode() == Instruction::Shl &&
-              isa<ConstantInt>(Inst->getOperand(1))) {
-            ConstantInt *ShAmt = cast<ConstantInt>(Inst->getOperand(1));
-            uint32_t ShAmtVal = ShAmt->getLimitedValue(64);
-            Scale = ConstantInt::get(cast<IntegerType>(Inst->getType()),
-                                     1ULL << ShAmtVal);
-            NewIdx = Inst->getOperand(0);
-          } else if (Inst->getOpcode() == Instruction::Mul &&
-                     isa<ConstantInt>(Inst->getOperand(1))) {
-            Scale = cast<ConstantInt>(Inst->getOperand(1));
-            NewIdx = Inst->getOperand(0);
-          }
-        }
-        
-        // If the index will be to exactly the right offset with the scale taken
-        // out, perform the transformation. Note, we don't know whether Scale is
-        // signed or not. We'll use unsigned version of division/modulo
-        // operation after making sure Scale doesn't have the sign bit set.
-        if (ArrayEltSize && Scale && Scale->getSExtValue() >= 0LL &&
-            Scale->getZExtValue() % ArrayEltSize == 0) {
-          Scale = ConstantInt::get(Scale->getType(),
-                                   Scale->getZExtValue() / ArrayEltSize);
-          if (Scale->getZExtValue() != 1) {
-            Constant *C = ConstantExpr::getIntegerCast(Scale, NewIdx->getType(),
-                                                       false /*ZExt*/);
-            NewIdx = Builder->CreateMul(NewIdx, C, "idxscale");
-          }
-
-          // Insert the new GEP instruction.
-          Value *Idx[2];
-          Idx[0] = Constant::getNullValue(Type::getInt32Ty(*Context));
-          Idx[1] = NewIdx;
-          Value *NewGEP = cast<GEPOperator>(&GEP)->isInBounds() ?
-            Builder->CreateInBoundsGEP(X, Idx, Idx + 2, GEP.getName()) :
-            Builder->CreateGEP(X, Idx, Idx + 2, GEP.getName());
-          // The NewGEP must be pointer typed, so must the old one -> BitCast
-          return new BitCastInst(NewGEP, GEP.getType());
-        }
-      }
-    }
-  }
-  
-  /// See if we can simplify:
-  ///   X = bitcast A* to B*
-  ///   Y = gep X, <...constant indices...>
-  /// into a gep of the original struct.  This is important for SROA and alias
-  /// analysis of unions.  If "A" is also a bitcast, wait for A/X to be merged.
-  if (BitCastInst *BCI = dyn_cast<BitCastInst>(PtrOp)) {
-    if (TD &&
-        !isa<BitCastInst>(BCI->getOperand(0)) && GEP.hasAllConstantIndices()) {
-      // Determine how much the GEP moves the pointer.  We are guaranteed to get
-      // a constant back from EmitGEPOffset.
-      ConstantInt *OffsetV = cast<ConstantInt>(EmitGEPOffset(&GEP, *this));
-      int64_t Offset = OffsetV->getSExtValue();
-      
-      // If this GEP instruction doesn't move the pointer, just replace the GEP
-      // with a bitcast of the real input to the dest type.
-      if (Offset == 0) {
-        // If the bitcast is of an allocation, and the allocation will be
-        // converted to match the type of the cast, don't touch this.
-        if (isa<AllocaInst>(BCI->getOperand(0)) ||
-            isMalloc(BCI->getOperand(0))) {
-          // See if the bitcast simplifies, if so, don't nuke this GEP yet.
-          if (Instruction *I = visitBitCast(*BCI)) {
-            if (I != BCI) {
-              I->takeName(BCI);
-              BCI->getParent()->getInstList().insert(BCI, I);
-              ReplaceInstUsesWith(*BCI, I);
-            }
-            return &GEP;
-          }
-        }
-        return new BitCastInst(BCI->getOperand(0), GEP.getType());
-      }
-      
-      // Otherwise, if the offset is non-zero, we need to find out if there is a
-      // field at Offset in 'A's type.  If so, we can pull the cast through the
-      // GEP.
-      SmallVector<Value*, 8> NewIndices;
-      const Type *InTy =
-        cast<PointerType>(BCI->getOperand(0)->getType())->getElementType();
-      if (FindElementAtOffset(InTy, Offset, NewIndices, TD, Context)) {
-        Value *NGEP = cast<GEPOperator>(&GEP)->isInBounds() ?
-          Builder->CreateInBoundsGEP(BCI->getOperand(0), NewIndices.begin(),
-                                     NewIndices.end()) :
-          Builder->CreateGEP(BCI->getOperand(0), NewIndices.begin(),
-                             NewIndices.end());
-        
-        if (NGEP->getType() == GEP.getType())
-          return ReplaceInstUsesWith(GEP, NGEP);
-        NGEP->takeName(&GEP);
-        return new BitCastInst(NGEP, GEP.getType());
-      }
-    }
-  }    
-    
-  return 0;
-}
-
-Instruction *InstCombiner::visitAllocaInst(AllocaInst &AI) {
-  // Convert: alloca Ty, C - where C is a constant != 1 into: alloca [C x Ty], 1
-  if (AI.isArrayAllocation()) {  // Check C != 1
-    if (const ConstantInt *C = dyn_cast<ConstantInt>(AI.getArraySize())) {
-      const Type *NewTy = 
-        ArrayType::get(AI.getAllocatedType(), C->getZExtValue());
-      assert(isa<AllocaInst>(AI) && "Unknown type of allocation inst!");
-      AllocaInst *New = Builder->CreateAlloca(NewTy, 0, AI.getName());
-      New->setAlignment(AI.getAlignment());
-
-      // Scan to the end of the allocation instructions, to skip over a block of
-      // allocas if possible...also skip interleaved debug info
-      //
-      BasicBlock::iterator It = New;
-      while (isa<AllocaInst>(*It) || isa<DbgInfoIntrinsic>(*It)) ++It;
-
-      // Now that I is pointing to the first non-allocation-inst in the block,
-      // insert our getelementptr instruction...
-      //
-      Value *NullIdx = Constant::getNullValue(Type::getInt32Ty(*Context));
-      Value *Idx[2];
-      Idx[0] = NullIdx;
-      Idx[1] = NullIdx;
-      Value *V = GetElementPtrInst::CreateInBounds(New, Idx, Idx + 2,
-                                                   New->getName()+".sub", It);
-
-      // Now make everything use the getelementptr instead of the original
-      // allocation.
-      return ReplaceInstUsesWith(AI, V);
-    } else if (isa<UndefValue>(AI.getArraySize())) {
-      return ReplaceInstUsesWith(AI, Constant::getNullValue(AI.getType()));
-    }
-  }
-
-  if (TD && isa<AllocaInst>(AI) && AI.getAllocatedType()->isSized()) {
-    // If alloca'ing a zero byte object, replace the alloca with a null pointer.
-    // Note that we only do this for alloca's, because malloc should allocate
-    // and return a unique pointer, even for a zero byte allocation.
-    if (TD->getTypeAllocSize(AI.getAllocatedType()) == 0)
-      return ReplaceInstUsesWith(AI, Constant::getNullValue(AI.getType()));
-
-    // If the alignment is 0 (unspecified), assign it the preferred alignment.
-    if (AI.getAlignment() == 0)
-      AI.setAlignment(TD->getPrefTypeAlignment(AI.getAllocatedType()));
-  }
-
-  return 0;
-}
-
-Instruction *InstCombiner::visitFree(Instruction &FI) {
-  Value *Op = FI.getOperand(1);
-
-  // free undef -> unreachable.
-  if (isa<UndefValue>(Op)) {
-    // Insert a new store to null because we cannot modify the CFG here.
-    new StoreInst(ConstantInt::getTrue(*Context),
-           UndefValue::get(Type::getInt1PtrTy(*Context)), &FI);
-    return EraseInstFromFunction(FI);
-  }
-  
-  // If we have 'free null' delete the instruction.  This can happen in stl code
-  // when lots of inlining happens.
-  if (isa<ConstantPointerNull>(Op))
-    return EraseInstFromFunction(FI);
-
-  // If we have a malloc call whose only use is a free call, delete both.
-  if (isMalloc(Op)) {
-    if (CallInst* CI = extractMallocCallFromBitCast(Op)) {
-      if (Op->hasOneUse() && CI->hasOneUse()) {
-        EraseInstFromFunction(FI);
-        EraseInstFromFunction(*CI);
-        return EraseInstFromFunction(*cast<Instruction>(Op));
-      }
-    } else {
-      // Op is a call to malloc
-      if (Op->hasOneUse()) {
-        EraseInstFromFunction(FI);
-        return EraseInstFromFunction(*cast<Instruction>(Op));
-      }
-    }
-  }
-
-  return 0;
-}
-
-/// InstCombineLoadCast - Fold 'load (cast P)' -> cast (load P)' when possible.
-static Instruction *InstCombineLoadCast(InstCombiner &IC, LoadInst &LI,
-                                        const TargetData *TD) {
-  User *CI = cast<User>(LI.getOperand(0));
-  Value *CastOp = CI->getOperand(0);
-  LLVMContext *Context = IC.getContext();
-
-  const PointerType *DestTy = cast<PointerType>(CI->getType());
-  const Type *DestPTy = DestTy->getElementType();
-  if (const PointerType *SrcTy = dyn_cast<PointerType>(CastOp->getType())) {
-
-    // If the address spaces don't match, don't eliminate the cast.
-    if (DestTy->getAddressSpace() != SrcTy->getAddressSpace())
-      return 0;
-
-    const Type *SrcPTy = SrcTy->getElementType();
-
-    if (DestPTy->isInteger() || isa<PointerType>(DestPTy) || 
-         isa<VectorType>(DestPTy)) {
-      // If the source is an array, the code below will not succeed.  Check to
-      // see if a trivial 'gep P, 0, 0' will help matters.  Only do this for
-      // constants.
-      if (const ArrayType *ASrcTy = dyn_cast<ArrayType>(SrcPTy))
-        if (Constant *CSrc = dyn_cast<Constant>(CastOp))
-          if (ASrcTy->getNumElements() != 0) {
-            Value *Idxs[2];
-            Idxs[0] = Constant::getNullValue(Type::getInt32Ty(*Context));
-            Idxs[1] = Idxs[0];
-            CastOp = ConstantExpr::getGetElementPtr(CSrc, Idxs, 2);
-            SrcTy = cast<PointerType>(CastOp->getType());
-            SrcPTy = SrcTy->getElementType();
-          }
-
-      if (IC.getTargetData() &&
-          (SrcPTy->isInteger() || isa<PointerType>(SrcPTy) || 
-            isa<VectorType>(SrcPTy)) &&
-          // Do not allow turning this into a load of an integer, which is then
-          // casted to a pointer, this pessimizes pointer analysis a lot.
-          (isa<PointerType>(SrcPTy) == isa<PointerType>(LI.getType())) &&
-          IC.getTargetData()->getTypeSizeInBits(SrcPTy) ==
-               IC.getTargetData()->getTypeSizeInBits(DestPTy)) {
-
-        // Okay, we are casting from one integer or pointer type to another of
-        // the same size.  Instead of casting the pointer before the load, cast
-        // the result of the loaded value.
-        Value *NewLoad = 
-          IC.Builder->CreateLoad(CastOp, LI.isVolatile(), CI->getName());
-        // Now cast the result of the load.
-        return new BitCastInst(NewLoad, LI.getType());
-      }
-    }
-  }
-  return 0;
-}
-
-Instruction *InstCombiner::visitLoadInst(LoadInst &LI) {
-  Value *Op = LI.getOperand(0);
-
-  // Attempt to improve the alignment.
-  if (TD) {
-    unsigned KnownAlign =
-      GetOrEnforceKnownAlignment(Op, TD->getPrefTypeAlignment(LI.getType()));
-    if (KnownAlign >
-        (LI.getAlignment() == 0 ? TD->getABITypeAlignment(LI.getType()) :
-                                  LI.getAlignment()))
-      LI.setAlignment(KnownAlign);
-  }
-
-  // load (cast X) --> cast (load X) iff safe.
-  if (isa<CastInst>(Op))
-    if (Instruction *Res = InstCombineLoadCast(*this, LI, TD))
-      return Res;
-
-  // None of the following transforms are legal for volatile loads.
-  if (LI.isVolatile()) return 0;
-  
-  // Do really simple store-to-load forwarding and load CSE, to catch cases
-  // where there are several consequtive memory accesses to the same location,
-  // separated by a few arithmetic operations.
-  BasicBlock::iterator BBI = &LI;
-  if (Value *AvailableVal = FindAvailableLoadedValue(Op, LI.getParent(), BBI,6))
-    return ReplaceInstUsesWith(LI, AvailableVal);
-
-  // load(gep null, ...) -> unreachable
-  if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(Op)) {
-    const Value *GEPI0 = GEPI->getOperand(0);
-    // TODO: Consider a target hook for valid address spaces for this xform.
-    if (isa<ConstantPointerNull>(GEPI0) && GEPI->getPointerAddressSpace() == 0){
-      // Insert a new store to null instruction before the load to indicate
-      // that this code is not reachable.  We do this instead of inserting
-      // an unreachable instruction directly because we cannot modify the
-      // CFG.
-      new StoreInst(UndefValue::get(LI.getType()),
-                    Constant::getNullValue(Op->getType()), &LI);
-      return ReplaceInstUsesWith(LI, UndefValue::get(LI.getType()));
-    }
-  } 
-
-  // load null/undef -> unreachable
-  // TODO: Consider a target hook for valid address spaces for this xform.
-  if (isa<UndefValue>(Op) ||
-      (isa<ConstantPointerNull>(Op) && LI.getPointerAddressSpace() == 0)) {
-    // Insert a new store to null instruction before the load to indicate that
-    // this code is not reachable.  We do this instead of inserting an
-    // unreachable instruction directly because we cannot modify the CFG.
-    new StoreInst(UndefValue::get(LI.getType()),
-                  Constant::getNullValue(Op->getType()), &LI);
-    return ReplaceInstUsesWith(LI, UndefValue::get(LI.getType()));
-  }
-
-  // Instcombine load (constantexpr_cast global) -> cast (load global)
-  if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Op))
-    if (CE->isCast())
-      if (Instruction *Res = InstCombineLoadCast(*this, LI, TD))
-        return Res;
-  
-  if (Op->hasOneUse()) {
-    // Change select and PHI nodes to select values instead of addresses: this
-    // helps alias analysis out a lot, allows many others simplifications, and
-    // exposes redundancy in the code.
-    //
-    // Note that we cannot do the transformation unless we know that the
-    // introduced loads cannot trap!  Something like this is valid as long as
-    // the condition is always false: load (select bool %C, int* null, int* %G),
-    // but it would not be valid if we transformed it to load from null
-    // unconditionally.
-    //
-    if (SelectInst *SI = dyn_cast<SelectInst>(Op)) {
-      // load (select (Cond, &V1, &V2))  --> select(Cond, load &V1, load &V2).
-      if (isSafeToLoadUnconditionally(SI->getOperand(1), SI) &&
-          isSafeToLoadUnconditionally(SI->getOperand(2), SI)) {
-        Value *V1 = Builder->CreateLoad(SI->getOperand(1),
-                                        SI->getOperand(1)->getName()+".val");
-        Value *V2 = Builder->CreateLoad(SI->getOperand(2),
-                                        SI->getOperand(2)->getName()+".val");
-        return SelectInst::Create(SI->getCondition(), V1, V2);
-      }
-
-      // load (select (cond, null, P)) -> load P
-      if (Constant *C = dyn_cast<Constant>(SI->getOperand(1)))
-        if (C->isNullValue()) {
-          LI.setOperand(0, SI->getOperand(2));
-          return &LI;
-        }
-
-      // load (select (cond, P, null)) -> load P
-      if (Constant *C = dyn_cast<Constant>(SI->getOperand(2)))
-        if (C->isNullValue()) {
-          LI.setOperand(0, SI->getOperand(1));
-          return &LI;
-        }
-    }
-  }
-  return 0;
-}
-
-/// InstCombineStoreToCast - Fold store V, (cast P) -> store (cast V), P
-/// when possible.  This makes it generally easy to do alias analysis and/or
-/// SROA/mem2reg of the memory object.
-static Instruction *InstCombineStoreToCast(InstCombiner &IC, StoreInst &SI) {
-  User *CI = cast<User>(SI.getOperand(1));
-  Value *CastOp = CI->getOperand(0);
-
-  const Type *DestPTy = cast<PointerType>(CI->getType())->getElementType();
-  const PointerType *SrcTy = dyn_cast<PointerType>(CastOp->getType());
-  if (SrcTy == 0) return 0;
-  
-  const Type *SrcPTy = SrcTy->getElementType();
-
-  if (!DestPTy->isInteger() && !isa<PointerType>(DestPTy))
-    return 0;
-  
-  /// NewGEPIndices - If SrcPTy is an aggregate type, we can emit a "noop gep"
-  /// to its first element.  This allows us to handle things like:
-  ///   store i32 xxx, (bitcast {foo*, float}* %P to i32*)
-  /// on 32-bit hosts.
-  SmallVector<Value*, 4> NewGEPIndices;
-  
-  // If the source is an array, the code below will not succeed.  Check to
-  // see if a trivial 'gep P, 0, 0' will help matters.  Only do this for
-  // constants.
-  if (isa<ArrayType>(SrcPTy) || isa<StructType>(SrcPTy)) {
-    // Index through pointer.
-    Constant *Zero = Constant::getNullValue(Type::getInt32Ty(*IC.getContext()));
-    NewGEPIndices.push_back(Zero);
-    
-    while (1) {
-      if (const StructType *STy = dyn_cast<StructType>(SrcPTy)) {
-        if (!STy->getNumElements()) /* Struct can be empty {} */
-          break;
-        NewGEPIndices.push_back(Zero);
-        SrcPTy = STy->getElementType(0);
-      } else if (const ArrayType *ATy = dyn_cast<ArrayType>(SrcPTy)) {
-        NewGEPIndices.push_back(Zero);
-        SrcPTy = ATy->getElementType();
-      } else {
-        break;
-      }
-    }
-    
-    SrcTy = PointerType::get(SrcPTy, SrcTy->getAddressSpace());
-  }
-
-  if (!SrcPTy->isInteger() && !isa<PointerType>(SrcPTy))
-    return 0;
-  
-  // If the pointers point into different address spaces or if they point to
-  // values with different sizes, we can't do the transformation.
-  if (!IC.getTargetData() ||
-      SrcTy->getAddressSpace() != 
-        cast<PointerType>(CI->getType())->getAddressSpace() ||
-      IC.getTargetData()->getTypeSizeInBits(SrcPTy) !=
-      IC.getTargetData()->getTypeSizeInBits(DestPTy))
-    return 0;
-
-  // Okay, we are casting from one integer or pointer type to another of
-  // the same size.  Instead of casting the pointer before 
-  // the store, cast the value to be stored.
-  Value *NewCast;
-  Value *SIOp0 = SI.getOperand(0);
-  Instruction::CastOps opcode = Instruction::BitCast;
-  const Type* CastSrcTy = SIOp0->getType();
-  const Type* CastDstTy = SrcPTy;
-  if (isa<PointerType>(CastDstTy)) {
-    if (CastSrcTy->isInteger())
-      opcode = Instruction::IntToPtr;
-  } else if (isa<IntegerType>(CastDstTy)) {
-    if (isa<PointerType>(SIOp0->getType()))
-      opcode = Instruction::PtrToInt;
-  }
-  
-  // SIOp0 is a pointer to aggregate and this is a store to the first field,
-  // emit a GEP to index into its first field.
-  if (!NewGEPIndices.empty())
-    CastOp = IC.Builder->CreateInBoundsGEP(CastOp, NewGEPIndices.begin(),
-                                           NewGEPIndices.end());
-  
-  NewCast = IC.Builder->CreateCast(opcode, SIOp0, CastDstTy,
-                                   SIOp0->getName()+".c");
-  return new StoreInst(NewCast, CastOp);
-}
-
-/// equivalentAddressValues - Test if A and B will obviously have the same
-/// value. This includes recognizing that %t0 and %t1 will have the same
-/// value in code like this:
-///   %t0 = getelementptr \@a, 0, 3
-///   store i32 0, i32* %t0
-///   %t1 = getelementptr \@a, 0, 3
-///   %t2 = load i32* %t1
-///
-static bool equivalentAddressValues(Value *A, Value *B) {
-  // Test if the values are trivially equivalent.
-  if (A == B) return true;
-  
-  // Test if the values come form identical arithmetic instructions.
-  // This uses isIdenticalToWhenDefined instead of isIdenticalTo because
-  // its only used to compare two uses within the same basic block, which
-  // means that they'll always either have the same value or one of them
-  // will have an undefined value.
-  if (isa<BinaryOperator>(A) ||
-      isa<CastInst>(A) ||
-      isa<PHINode>(A) ||
-      isa<GetElementPtrInst>(A))
-    if (Instruction *BI = dyn_cast<Instruction>(B))
-      if (cast<Instruction>(A)->isIdenticalToWhenDefined(BI))
-        return true;
-  
-  // Otherwise they may not be equivalent.
-  return false;
-}
-
-// If this instruction has two uses, one of which is a llvm.dbg.declare,
-// return the llvm.dbg.declare.
-DbgDeclareInst *InstCombiner::hasOneUsePlusDeclare(Value *V) {
-  if (!V->hasNUses(2))
-    return 0;
-  for (Value::use_iterator UI = V->use_begin(), E = V->use_end();
-       UI != E; ++UI) {
-    if (DbgDeclareInst *DI = dyn_cast<DbgDeclareInst>(UI))
-      return DI;
-    if (isa<BitCastInst>(UI) && UI->hasOneUse()) {
-      if (DbgDeclareInst *DI = dyn_cast<DbgDeclareInst>(UI->use_begin()))
-        return DI;
-      }
-  }
-  return 0;
-}
-
-Instruction *InstCombiner::visitStoreInst(StoreInst &SI) {
-  Value *Val = SI.getOperand(0);
-  Value *Ptr = SI.getOperand(1);
-
-  // If the RHS is an alloca with a single use, zapify the store, making the
-  // alloca dead.
-  // If the RHS is an alloca with a two uses, the other one being a 
-  // llvm.dbg.declare, zapify the store and the declare, making the
-  // alloca dead.  We must do this to prevent declare's from affecting
-  // codegen.
-  if (!SI.isVolatile()) {
-    if (Ptr->hasOneUse()) {
-      if (isa<AllocaInst>(Ptr)) {
-        EraseInstFromFunction(SI);
-        ++NumCombined;
-        return 0;
-      }
-      if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Ptr)) {
-        if (isa<AllocaInst>(GEP->getOperand(0))) {
-          if (GEP->getOperand(0)->hasOneUse()) {
-            EraseInstFromFunction(SI);
-            ++NumCombined;
-            return 0;
-          }
-          if (DbgDeclareInst *DI = hasOneUsePlusDeclare(GEP->getOperand(0))) {
-            EraseInstFromFunction(*DI);
-            EraseInstFromFunction(SI);
-            ++NumCombined;
-            return 0;
-          }
-        }
-      }
-    }
-    if (DbgDeclareInst *DI = hasOneUsePlusDeclare(Ptr)) {
-      EraseInstFromFunction(*DI);
-      EraseInstFromFunction(SI);
-      ++NumCombined;
-      return 0;
-    }
-  }
-
-  // Attempt to improve the alignment.
-  if (TD) {
-    unsigned KnownAlign =
-      GetOrEnforceKnownAlignment(Ptr, TD->getPrefTypeAlignment(Val->getType()));
-    if (KnownAlign >
-        (SI.getAlignment() == 0 ? TD->getABITypeAlignment(Val->getType()) :
-                                  SI.getAlignment()))
-      SI.setAlignment(KnownAlign);
-  }
-
-  // Do really simple DSE, to catch cases where there are several consecutive
-  // stores to the same location, separated by a few arithmetic operations. This
-  // situation often occurs with bitfield accesses.
-  BasicBlock::iterator BBI = &SI;
-  for (unsigned ScanInsts = 6; BBI != SI.getParent()->begin() && ScanInsts;
-       --ScanInsts) {
-    --BBI;
-    // Don't count debug info directives, lest they affect codegen,
-    // and we skip pointer-to-pointer bitcasts, which are NOPs.
-    // It is necessary for correctness to skip those that feed into a
-    // llvm.dbg.declare, as these are not present when debugging is off.
-    if (isa<DbgInfoIntrinsic>(BBI) ||
-        (isa<BitCastInst>(BBI) && isa<PointerType>(BBI->getType()))) {
-      ScanInsts++;
-      continue;
-    }    
-    
-    if (StoreInst *PrevSI = dyn_cast<StoreInst>(BBI)) {
-      // Prev store isn't volatile, and stores to the same location?
-      if (!PrevSI->isVolatile() &&equivalentAddressValues(PrevSI->getOperand(1),
-                                                          SI.getOperand(1))) {
-        ++NumDeadStore;
-        ++BBI;
-        EraseInstFromFunction(*PrevSI);
-        continue;
-      }
-      break;
-    }
-    
-    // If this is a load, we have to stop.  However, if the loaded value is from
-    // the pointer we're loading and is producing the pointer we're storing,
-    // then *this* store is dead (X = load P; store X -> P).
-    if (LoadInst *LI = dyn_cast<LoadInst>(BBI)) {
-      if (LI == Val && equivalentAddressValues(LI->getOperand(0), Ptr) &&
-          !SI.isVolatile()) {
-        EraseInstFromFunction(SI);
-        ++NumCombined;
-        return 0;
-      }
-      // Otherwise, this is a load from some other location.  Stores before it
-      // may not be dead.
-      break;
-    }
-    
-    // Don't skip over loads or things that can modify memory.
-    if (BBI->mayWriteToMemory() || BBI->mayReadFromMemory())
-      break;
-  }
-  
-  
-  if (SI.isVolatile()) return 0;  // Don't hack volatile stores.
-
-  // store X, null    -> turns into 'unreachable' in SimplifyCFG
-  if (isa<ConstantPointerNull>(Ptr) && SI.getPointerAddressSpace() == 0) {
-    if (!isa<UndefValue>(Val)) {
-      SI.setOperand(0, UndefValue::get(Val->getType()));
-      if (Instruction *U = dyn_cast<Instruction>(Val))
-        Worklist.Add(U);  // Dropped a use.
-      ++NumCombined;
-    }
-    return 0;  // Do not modify these!
-  }
-
-  // store undef, Ptr -> noop
-  if (isa<UndefValue>(Val)) {
-    EraseInstFromFunction(SI);
-    ++NumCombined;
-    return 0;
-  }
-
-  // If the pointer destination is a cast, see if we can fold the cast into the
-  // source instead.
-  if (isa<CastInst>(Ptr))
-    if (Instruction *Res = InstCombineStoreToCast(*this, SI))
-      return Res;
-  if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ptr))
-    if (CE->isCast())
-      if (Instruction *Res = InstCombineStoreToCast(*this, SI))
-        return Res;
-
-  
-  // If this store is the last instruction in the basic block (possibly
-  // excepting debug info instructions and the pointer bitcasts that feed
-  // into them), and if the block ends with an unconditional branch, try
-  // to move it to the successor block.
-  BBI = &SI; 
-  do {
-    ++BBI;
-  } while (isa<DbgInfoIntrinsic>(BBI) ||
-           (isa<BitCastInst>(BBI) && isa<PointerType>(BBI->getType())));
-  if (BranchInst *BI = dyn_cast<BranchInst>(BBI))
-    if (BI->isUnconditional())
-      if (SimplifyStoreAtEndOfBlock(SI))
-        return 0;  // xform done!
-  
-  return 0;
-}
-
-/// SimplifyStoreAtEndOfBlock - Turn things like:
-///   if () { *P = v1; } else { *P = v2 }
-/// into a phi node with a store in the successor.
-///
-/// Simplify things like:
-///   *P = v1; if () { *P = v2; }
-/// into a phi node with a store in the successor.
-///
-bool InstCombiner::SimplifyStoreAtEndOfBlock(StoreInst &SI) {
-  BasicBlock *StoreBB = SI.getParent();
-  
-  // Check to see if the successor block has exactly two incoming edges.  If
-  // so, see if the other predecessor contains a store to the same location.
-  // if so, insert a PHI node (if needed) and move the stores down.
-  BasicBlock *DestBB = StoreBB->getTerminator()->getSuccessor(0);
-  
-  // Determine whether Dest has exactly two predecessors and, if so, compute
-  // the other predecessor.
-  pred_iterator PI = pred_begin(DestBB);
-  BasicBlock *OtherBB = 0;
-  if (*PI != StoreBB)
-    OtherBB = *PI;
-  ++PI;
-  if (PI == pred_end(DestBB))
-    return false;
-  
-  if (*PI != StoreBB) {
-    if (OtherBB)
-      return false;
-    OtherBB = *PI;
-  }
-  if (++PI != pred_end(DestBB))
-    return false;
-
-  // Bail out if all the relevant blocks aren't distinct (this can happen,
-  // for example, if SI is in an infinite loop)
-  if (StoreBB == DestBB || OtherBB == DestBB)
-    return false;
-
-  // Verify that the other block ends in a branch and is not otherwise empty.
-  BasicBlock::iterator BBI = OtherBB->getTerminator();
-  BranchInst *OtherBr = dyn_cast<BranchInst>(BBI);
-  if (!OtherBr || BBI == OtherBB->begin())
-    return false;
-  
-  // If the other block ends in an unconditional branch, check for the 'if then
-  // else' case.  there is an instruction before the branch.
-  StoreInst *OtherStore = 0;
-  if (OtherBr->isUnconditional()) {
-    --BBI;
-    // Skip over debugging info.
-    while (isa<DbgInfoIntrinsic>(BBI) ||
-           (isa<BitCastInst>(BBI) && isa<PointerType>(BBI->getType()))) {
-      if (BBI==OtherBB->begin())
-        return false;
-      --BBI;
-    }
-    // If this isn't a store, isn't a store to the same location, or if the
-    // alignments differ, bail out.
-    OtherStore = dyn_cast<StoreInst>(BBI);
-    if (!OtherStore || OtherStore->getOperand(1) != SI.getOperand(1) ||
-        OtherStore->getAlignment() != SI.getAlignment())
-      return false;
-  } else {
-    // Otherwise, the other block ended with a conditional branch. If one of the
-    // destinations is StoreBB, then we have the if/then case.
-    if (OtherBr->getSuccessor(0) != StoreBB && 
-        OtherBr->getSuccessor(1) != StoreBB)
-      return false;
-    
-    // Okay, we know that OtherBr now goes to Dest and StoreBB, so this is an
-    // if/then triangle.  See if there is a store to the same ptr as SI that
-    // lives in OtherBB.
-    for (;; --BBI) {
-      // Check to see if we find the matching store.
-      if ((OtherStore = dyn_cast<StoreInst>(BBI))) {
-        if (OtherStore->getOperand(1) != SI.getOperand(1) ||
-            OtherStore->getAlignment() != SI.getAlignment())
-          return false;
-        break;
-      }
-      // If we find something that may be using or overwriting the stored
-      // value, or if we run out of instructions, we can't do the xform.
-      if (BBI->mayReadFromMemory() || BBI->mayWriteToMemory() ||
-          BBI == OtherBB->begin())
-        return false;
-    }
-    
-    // In order to eliminate the store in OtherBr, we have to
-    // make sure nothing reads or overwrites the stored value in
-    // StoreBB.
-    for (BasicBlock::iterator I = StoreBB->begin(); &*I != &SI; ++I) {
-      // FIXME: This should really be AA driven.
-      if (I->mayReadFromMemory() || I->mayWriteToMemory())
-        return false;
-    }
-  }
-  
-  // Insert a PHI node now if we need it.
-  Value *MergedVal = OtherStore->getOperand(0);
-  if (MergedVal != SI.getOperand(0)) {
-    PHINode *PN = PHINode::Create(MergedVal->getType(), "storemerge");
-    PN->reserveOperandSpace(2);
-    PN->addIncoming(SI.getOperand(0), SI.getParent());
-    PN->addIncoming(OtherStore->getOperand(0), OtherBB);
-    MergedVal = InsertNewInstBefore(PN, DestBB->front());
-  }
-  
-  // Advance to a place where it is safe to insert the new store and
-  // insert it.
-  BBI = DestBB->getFirstNonPHI();
-  InsertNewInstBefore(new StoreInst(MergedVal, SI.getOperand(1),
-                                    OtherStore->isVolatile(),
-                                    SI.getAlignment()), *BBI);
-  
-  // Nuke the old stores.
-  EraseInstFromFunction(SI);
-  EraseInstFromFunction(*OtherStore);
-  ++NumCombined;
-  return true;
-}
-
-
-Instruction *InstCombiner::visitBranchInst(BranchInst &BI) {
-  // Change br (not X), label True, label False to: br X, label False, True
-  Value *X = 0;
-  BasicBlock *TrueDest;
-  BasicBlock *FalseDest;
-  if (match(&BI, m_Br(m_Not(m_Value(X)), TrueDest, FalseDest)) &&
-      !isa<Constant>(X)) {
-    // Swap Destinations and condition...
-    BI.setCondition(X);
-    BI.setSuccessor(0, FalseDest);
-    BI.setSuccessor(1, TrueDest);
-    return &BI;
-  }
-
-  // Cannonicalize fcmp_one -> fcmp_oeq
-  FCmpInst::Predicate FPred; Value *Y;
-  if (match(&BI, m_Br(m_FCmp(FPred, m_Value(X), m_Value(Y)), 
-                             TrueDest, FalseDest)) &&
-      BI.getCondition()->hasOneUse())
-    if (FPred == FCmpInst::FCMP_ONE || FPred == FCmpInst::FCMP_OLE ||
-        FPred == FCmpInst::FCMP_OGE) {
-      FCmpInst *Cond = cast<FCmpInst>(BI.getCondition());
-      Cond->setPredicate(FCmpInst::getInversePredicate(FPred));
-      
-      // Swap Destinations and condition.
-      BI.setSuccessor(0, FalseDest);
-      BI.setSuccessor(1, TrueDest);
-      Worklist.Add(Cond);
-      return &BI;
-    }
-
-  // Cannonicalize icmp_ne -> icmp_eq
-  ICmpInst::Predicate IPred;
-  if (match(&BI, m_Br(m_ICmp(IPred, m_Value(X), m_Value(Y)),
-                      TrueDest, FalseDest)) &&
-      BI.getCondition()->hasOneUse())
-    if (IPred == ICmpInst::ICMP_NE  || IPred == ICmpInst::ICMP_ULE ||
-        IPred == ICmpInst::ICMP_SLE || IPred == ICmpInst::ICMP_UGE ||
-        IPred == ICmpInst::ICMP_SGE) {
-      ICmpInst *Cond = cast<ICmpInst>(BI.getCondition());
-      Cond->setPredicate(ICmpInst::getInversePredicate(IPred));
-      // Swap Destinations and condition.
-      BI.setSuccessor(0, FalseDest);
-      BI.setSuccessor(1, TrueDest);
-      Worklist.Add(Cond);
-      return &BI;
-    }
-
-  return 0;
-}
-
-Instruction *InstCombiner::visitSwitchInst(SwitchInst &SI) {
-  Value *Cond = SI.getCondition();
-  if (Instruction *I = dyn_cast<Instruction>(Cond)) {
-    if (I->getOpcode() == Instruction::Add)
-      if (ConstantInt *AddRHS = dyn_cast<ConstantInt>(I->getOperand(1))) {
-        // change 'switch (X+4) case 1:' into 'switch (X) case -3'
-        for (unsigned i = 2, e = SI.getNumOperands(); i != e; i += 2)
-          SI.setOperand(i,
-                   ConstantExpr::getSub(cast<Constant>(SI.getOperand(i)),
-                                                AddRHS));
-        SI.setOperand(0, I->getOperand(0));
-        Worklist.Add(I);
-        return &SI;
-      }
-  }
-  return 0;
-}
-
-Instruction *InstCombiner::visitExtractValueInst(ExtractValueInst &EV) {
-  Value *Agg = EV.getAggregateOperand();
-
-  if (!EV.hasIndices())
-    return ReplaceInstUsesWith(EV, Agg);
-
-  if (Constant *C = dyn_cast<Constant>(Agg)) {
-    if (isa<UndefValue>(C))
-      return ReplaceInstUsesWith(EV, UndefValue::get(EV.getType()));
-      
-    if (isa<ConstantAggregateZero>(C))
-      return ReplaceInstUsesWith(EV, Constant::getNullValue(EV.getType()));
-
-    if (isa<ConstantArray>(C) || isa<ConstantStruct>(C)) {
-      // Extract the element indexed by the first index out of the constant
-      Value *V = C->getOperand(*EV.idx_begin());
-      if (EV.getNumIndices() > 1)
-        // Extract the remaining indices out of the constant indexed by the
-        // first index
-        return ExtractValueInst::Create(V, EV.idx_begin() + 1, EV.idx_end());
-      else
-        return ReplaceInstUsesWith(EV, V);
-    }
-    return 0; // Can't handle other constants
-  } 
-  if (InsertValueInst *IV = dyn_cast<InsertValueInst>(Agg)) {
-    // We're extracting from an insertvalue instruction, compare the indices
-    const unsigned *exti, *exte, *insi, *inse;
-    for (exti = EV.idx_begin(), insi = IV->idx_begin(),
-         exte = EV.idx_end(), inse = IV->idx_end();
-         exti != exte && insi != inse;
-         ++exti, ++insi) {
-      if (*insi != *exti)
-        // The insert and extract both reference distinctly different elements.
-        // This means the extract is not influenced by the insert, and we can
-        // replace the aggregate operand of the extract with the aggregate
-        // operand of the insert. i.e., replace
-        // %I = insertvalue { i32, { i32 } } %A, { i32 } { i32 42 }, 1
-        // %E = extractvalue { i32, { i32 } } %I, 0
-        // with
-        // %E = extractvalue { i32, { i32 } } %A, 0
-        return ExtractValueInst::Create(IV->getAggregateOperand(),
-                                        EV.idx_begin(), EV.idx_end());
-    }
-    if (exti == exte && insi == inse)
-      // Both iterators are at the end: Index lists are identical. Replace
-      // %B = insertvalue { i32, { i32 } } %A, i32 42, 1, 0
-      // %C = extractvalue { i32, { i32 } } %B, 1, 0
-      // with "i32 42"
-      return ReplaceInstUsesWith(EV, IV->getInsertedValueOperand());
-    if (exti == exte) {
-      // The extract list is a prefix of the insert list. i.e. replace
-      // %I = insertvalue { i32, { i32 } } %A, i32 42, 1, 0
-      // %E = extractvalue { i32, { i32 } } %I, 1
-      // with
-      // %X = extractvalue { i32, { i32 } } %A, 1
-      // %E = insertvalue { i32 } %X, i32 42, 0
-      // by switching the order of the insert and extract (though the
-      // insertvalue should be left in, since it may have other uses).
-      Value *NewEV = Builder->CreateExtractValue(IV->getAggregateOperand(),
-                                                 EV.idx_begin(), EV.idx_end());
-      return InsertValueInst::Create(NewEV, IV->getInsertedValueOperand(),
-                                     insi, inse);
-    }
-    if (insi == inse)
-      // The insert list is a prefix of the extract list
-      // We can simply remove the common indices from the extract and make it
-      // operate on the inserted value instead of the insertvalue result.
-      // i.e., replace
-      // %I = insertvalue { i32, { i32 } } %A, { i32 } { i32 42 }, 1
-      // %E = extractvalue { i32, { i32 } } %I, 1, 0
-      // with
-      // %E extractvalue { i32 } { i32 42 }, 0
-      return ExtractValueInst::Create(IV->getInsertedValueOperand(), 
-                                      exti, exte);
-  }
-  if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Agg)) {
-    // We're extracting from an intrinsic, see if we're the only user, which
-    // allows us to simplify multiple result intrinsics to simpler things that
-    // just get one value..
-    if (II->hasOneUse()) {
-      // Check if we're grabbing the overflow bit or the result of a 'with
-      // overflow' intrinsic.  If it's the latter we can remove the intrinsic
-      // and replace it with a traditional binary instruction.
-      switch (II->getIntrinsicID()) {
-      case Intrinsic::uadd_with_overflow:
-      case Intrinsic::sadd_with_overflow:
-        if (*EV.idx_begin() == 0) {  // Normal result.
-          Value *LHS = II->getOperand(1), *RHS = II->getOperand(2);
-          II->replaceAllUsesWith(UndefValue::get(II->getType()));
-          EraseInstFromFunction(*II);
-          return BinaryOperator::CreateAdd(LHS, RHS);
-        }
-        break;
-      case Intrinsic::usub_with_overflow:
-      case Intrinsic::ssub_with_overflow:
-        if (*EV.idx_begin() == 0) {  // Normal result.
-          Value *LHS = II->getOperand(1), *RHS = II->getOperand(2);
-          II->replaceAllUsesWith(UndefValue::get(II->getType()));
-          EraseInstFromFunction(*II);
-          return BinaryOperator::CreateSub(LHS, RHS);
-        }
-        break;
-      case Intrinsic::umul_with_overflow:
-      case Intrinsic::smul_with_overflow:
-        if (*EV.idx_begin() == 0) {  // Normal result.
-          Value *LHS = II->getOperand(1), *RHS = II->getOperand(2);
-          II->replaceAllUsesWith(UndefValue::get(II->getType()));
-          EraseInstFromFunction(*II);
-          return BinaryOperator::CreateMul(LHS, RHS);
-        }
-        break;
-      default:
-        break;
-      }
-    }
-  }
-  // Can't simplify extracts from other values. Note that nested extracts are
-  // already simplified implicitely by the above (extract ( extract (insert) )
-  // will be translated into extract ( insert ( extract ) ) first and then just
-  // the value inserted, if appropriate).
-  return 0;
-}
-
-/// CheapToScalarize - Return true if the value is cheaper to scalarize than it
-/// is to leave as a vector operation.
-static bool CheapToScalarize(Value *V, bool isConstant) {
-  if (isa<ConstantAggregateZero>(V)) 
-    return true;
-  if (ConstantVector *C = dyn_cast<ConstantVector>(V)) {
-    if (isConstant) return true;
-    // If all elts are the same, we can extract.
-    Constant *Op0 = C->getOperand(0);
-    for (unsigned i = 1; i < C->getNumOperands(); ++i)
-      if (C->getOperand(i) != Op0)
-        return false;
-    return true;
-  }
-  Instruction *I = dyn_cast<Instruction>(V);
-  if (!I) return false;
-  
-  // Insert element gets simplified to the inserted element or is deleted if
-  // this is constant idx extract element and its a constant idx insertelt.
-  if (I->getOpcode() == Instruction::InsertElement && isConstant &&
-      isa<ConstantInt>(I->getOperand(2)))
-    return true;
-  if (I->getOpcode() == Instruction::Load && I->hasOneUse())
-    return true;
-  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(I))
-    if (BO->hasOneUse() &&
-        (CheapToScalarize(BO->getOperand(0), isConstant) ||
-         CheapToScalarize(BO->getOperand(1), isConstant)))
-      return true;
-  if (CmpInst *CI = dyn_cast<CmpInst>(I))
-    if (CI->hasOneUse() &&
-        (CheapToScalarize(CI->getOperand(0), isConstant) ||
-         CheapToScalarize(CI->getOperand(1), isConstant)))
-      return true;
-  
-  return false;
-}
-
-/// Read and decode a shufflevector mask.
-///
-/// It turns undef elements into values that are larger than the number of
-/// elements in the input.
-static std::vector<unsigned> getShuffleMask(const ShuffleVectorInst *SVI) {
-  unsigned NElts = SVI->getType()->getNumElements();
-  if (isa<ConstantAggregateZero>(SVI->getOperand(2)))
-    return std::vector<unsigned>(NElts, 0);
-  if (isa<UndefValue>(SVI->getOperand(2)))
-    return std::vector<unsigned>(NElts, 2*NElts);
-
-  std::vector<unsigned> Result;
-  const ConstantVector *CP = cast<ConstantVector>(SVI->getOperand(2));
-  for (User::const_op_iterator i = CP->op_begin(), e = CP->op_end(); i!=e; ++i)
-    if (isa<UndefValue>(*i))
-      Result.push_back(NElts*2);  // undef -> 8
-    else
-      Result.push_back(cast<ConstantInt>(*i)->getZExtValue());
-  return Result;
-}
-
-/// FindScalarElement - Given a vector and an element number, see if the scalar
-/// value is already around as a register, for example if it were inserted then
-/// extracted from the vector.
-static Value *FindScalarElement(Value *V, unsigned EltNo,
-                                LLVMContext *Context) {
-  assert(isa<VectorType>(V->getType()) && "Not looking at a vector?");
-  const VectorType *PTy = cast<VectorType>(V->getType());
-  unsigned Width = PTy->getNumElements();
-  if (EltNo >= Width)  // Out of range access.
-    return UndefValue::get(PTy->getElementType());
-  
-  if (isa<UndefValue>(V))
-    return UndefValue::get(PTy->getElementType());
-  else if (isa<ConstantAggregateZero>(V))
-    return Constant::getNullValue(PTy->getElementType());
-  else if (ConstantVector *CP = dyn_cast<ConstantVector>(V))
-    return CP->getOperand(EltNo);
-  else if (InsertElementInst *III = dyn_cast<InsertElementInst>(V)) {
-    // If this is an insert to a variable element, we don't know what it is.
-    if (!isa<ConstantInt>(III->getOperand(2))) 
-      return 0;
-    unsigned IIElt = cast<ConstantInt>(III->getOperand(2))->getZExtValue();
-    
-    // If this is an insert to the element we are looking for, return the
-    // inserted value.
-    if (EltNo == IIElt) 
-      return III->getOperand(1);
-    
-    // Otherwise, the insertelement doesn't modify the value, recurse on its
-    // vector input.
-    return FindScalarElement(III->getOperand(0), EltNo, Context);
-  } else if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(V)) {
-    unsigned LHSWidth =
-      cast<VectorType>(SVI->getOperand(0)->getType())->getNumElements();
-    unsigned InEl = getShuffleMask(SVI)[EltNo];
-    if (InEl < LHSWidth)
-      return FindScalarElement(SVI->getOperand(0), InEl, Context);
-    else if (InEl < LHSWidth*2)
-      return FindScalarElement(SVI->getOperand(1), InEl - LHSWidth, Context);
-    else
-      return UndefValue::get(PTy->getElementType());
-  }
-  
-  // Otherwise, we don't know.
-  return 0;
-}
-
-Instruction *InstCombiner::visitExtractElementInst(ExtractElementInst &EI) {
-  // If vector val is undef, replace extract with scalar undef.
-  if (isa<UndefValue>(EI.getOperand(0)))
-    return ReplaceInstUsesWith(EI, UndefValue::get(EI.getType()));
-
-  // If vector val is constant 0, replace extract with scalar 0.
-  if (isa<ConstantAggregateZero>(EI.getOperand(0)))
-    return ReplaceInstUsesWith(EI, Constant::getNullValue(EI.getType()));
-  
-  if (ConstantVector *C = dyn_cast<ConstantVector>(EI.getOperand(0))) {
-    // If vector val is constant with all elements the same, replace EI with
-    // that element. When the elements are not identical, we cannot replace yet
-    // (we do that below, but only when the index is constant).
-    Constant *op0 = C->getOperand(0);
-    for (unsigned i = 1; i != C->getNumOperands(); ++i)
-      if (C->getOperand(i) != op0) {
-        op0 = 0; 
-        break;
-      }
-    if (op0)
-      return ReplaceInstUsesWith(EI, op0);
-  }
-  
-  // If extracting a specified index from the vector, see if we can recursively
-  // find a previously computed scalar that was inserted into the vector.
-  if (ConstantInt *IdxC = dyn_cast<ConstantInt>(EI.getOperand(1))) {
-    unsigned IndexVal = IdxC->getZExtValue();
-    unsigned VectorWidth = EI.getVectorOperandType()->getNumElements();
-      
-    // If this is extracting an invalid index, turn this into undef, to avoid
-    // crashing the code below.
-    if (IndexVal >= VectorWidth)
-      return ReplaceInstUsesWith(EI, UndefValue::get(EI.getType()));
-    
-    // This instruction only demands the single element from the input vector.
-    // If the input vector has a single use, simplify it based on this use
-    // property.
-    if (EI.getOperand(0)->hasOneUse() && VectorWidth != 1) {
-      APInt UndefElts(VectorWidth, 0);
-      APInt DemandedMask(VectorWidth, 1 << IndexVal);
-      if (Value *V = SimplifyDemandedVectorElts(EI.getOperand(0),
-                                                DemandedMask, UndefElts)) {
-        EI.setOperand(0, V);
-        return &EI;
-      }
-    }
-    
-    if (Value *Elt = FindScalarElement(EI.getOperand(0), IndexVal, Context))
-      return ReplaceInstUsesWith(EI, Elt);
-    
-    // If the this extractelement is directly using a bitcast from a vector of
-    // the same number of elements, see if we can find the source element from
-    // it.  In this case, we will end up needing to bitcast the scalars.
-    if (BitCastInst *BCI = dyn_cast<BitCastInst>(EI.getOperand(0))) {
-      if (const VectorType *VT = 
-              dyn_cast<VectorType>(BCI->getOperand(0)->getType()))
-        if (VT->getNumElements() == VectorWidth)
-          if (Value *Elt = FindScalarElement(BCI->getOperand(0),
-                                             IndexVal, Context))
-            return new BitCastInst(Elt, EI.getType());
-    }
-  }
-  
-  if (Instruction *I = dyn_cast<Instruction>(EI.getOperand(0))) {
-    // Push extractelement into predecessor operation if legal and
-    // profitable to do so
-    if (BinaryOperator *BO = dyn_cast<BinaryOperator>(I)) {
-      if (I->hasOneUse() &&
-          CheapToScalarize(BO, isa<ConstantInt>(EI.getOperand(1)))) {
-        Value *newEI0 =
-          Builder->CreateExtractElement(BO->getOperand(0), EI.getOperand(1),
-                                        EI.getName()+".lhs");
-        Value *newEI1 =
-          Builder->CreateExtractElement(BO->getOperand(1), EI.getOperand(1),
-                                        EI.getName()+".rhs");
-        return BinaryOperator::Create(BO->getOpcode(), newEI0, newEI1);
-      }
-    } else if (InsertElementInst *IE = dyn_cast<InsertElementInst>(I)) {
-      // Extracting the inserted element?
-      if (IE->getOperand(2) == EI.getOperand(1))
-        return ReplaceInstUsesWith(EI, IE->getOperand(1));
-      // If the inserted and extracted elements are constants, they must not
-      // be the same value, extract from the pre-inserted value instead.
-      if (isa<Constant>(IE->getOperand(2)) && isa<Constant>(EI.getOperand(1))) {
-        Worklist.AddValue(EI.getOperand(0));
-        EI.setOperand(0, IE->getOperand(0));
-        return &EI;
-      }
-    } else if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(I)) {
-      // If this is extracting an element from a shufflevector, figure out where
-      // it came from and extract from the appropriate input element instead.
-      if (ConstantInt *Elt = dyn_cast<ConstantInt>(EI.getOperand(1))) {
-        unsigned SrcIdx = getShuffleMask(SVI)[Elt->getZExtValue()];
-        Value *Src;
-        unsigned LHSWidth =
-          cast<VectorType>(SVI->getOperand(0)->getType())->getNumElements();
-
-        if (SrcIdx < LHSWidth)
-          Src = SVI->getOperand(0);
-        else if (SrcIdx < LHSWidth*2) {
-          SrcIdx -= LHSWidth;
-          Src = SVI->getOperand(1);
-        } else {
-          return ReplaceInstUsesWith(EI, UndefValue::get(EI.getType()));
-        }
-        return ExtractElementInst::Create(Src,
-                         ConstantInt::get(Type::getInt32Ty(*Context), SrcIdx,
-                                          false));
-      }
-    }
-    // FIXME: Canonicalize extractelement(bitcast) -> bitcast(extractelement)
-  }
-  return 0;
-}
-
-/// CollectSingleShuffleElements - If V is a shuffle of values that ONLY returns
-/// elements from either LHS or RHS, return the shuffle mask and true. 
-/// Otherwise, return false.
-static bool CollectSingleShuffleElements(Value *V, Value *LHS, Value *RHS,
-                                         std::vector<Constant*> &Mask,
-                                         LLVMContext *Context) {
-  assert(V->getType() == LHS->getType() && V->getType() == RHS->getType() &&
-         "Invalid CollectSingleShuffleElements");
-  unsigned NumElts = cast<VectorType>(V->getType())->getNumElements();
-
-  if (isa<UndefValue>(V)) {
-    Mask.assign(NumElts, UndefValue::get(Type::getInt32Ty(*Context)));
-    return true;
-  } else if (V == LHS) {
-    for (unsigned i = 0; i != NumElts; ++i)
-      Mask.push_back(ConstantInt::get(Type::getInt32Ty(*Context), i));
-    return true;
-  } else if (V == RHS) {
-    for (unsigned i = 0; i != NumElts; ++i)
-      Mask.push_back(ConstantInt::get(Type::getInt32Ty(*Context), i+NumElts));
-    return true;
-  } else if (InsertElementInst *IEI = dyn_cast<InsertElementInst>(V)) {
-    // If this is an insert of an extract from some other vector, include it.
-    Value *VecOp    = IEI->getOperand(0);
-    Value *ScalarOp = IEI->getOperand(1);
-    Value *IdxOp    = IEI->getOperand(2);
-    
-    if (!isa<ConstantInt>(IdxOp))
-      return false;
-    unsigned InsertedIdx = cast<ConstantInt>(IdxOp)->getZExtValue();
-    
-    if (isa<UndefValue>(ScalarOp)) {  // inserting undef into vector.
-      // Okay, we can handle this if the vector we are insertinting into is
-      // transitively ok.
-      if (CollectSingleShuffleElements(VecOp, LHS, RHS, Mask, Context)) {
-        // If so, update the mask to reflect the inserted undef.
-        Mask[InsertedIdx] = UndefValue::get(Type::getInt32Ty(*Context));
-        return true;
-      }      
-    } else if (ExtractElementInst *EI = dyn_cast<ExtractElementInst>(ScalarOp)){
-      if (isa<ConstantInt>(EI->getOperand(1)) &&
-          EI->getOperand(0)->getType() == V->getType()) {
-        unsigned ExtractedIdx =
-          cast<ConstantInt>(EI->getOperand(1))->getZExtValue();
-        
-        // This must be extracting from either LHS or RHS.
-        if (EI->getOperand(0) == LHS || EI->getOperand(0) == RHS) {
-          // Okay, we can handle this if the vector we are insertinting into is
-          // transitively ok.
-          if (CollectSingleShuffleElements(VecOp, LHS, RHS, Mask, Context)) {
-            // If so, update the mask to reflect the inserted value.
-            if (EI->getOperand(0) == LHS) {
-              Mask[InsertedIdx % NumElts] = 
-                 ConstantInt::get(Type::getInt32Ty(*Context), ExtractedIdx);
-            } else {
-              assert(EI->getOperand(0) == RHS);
-              Mask[InsertedIdx % NumElts] = 
-                ConstantInt::get(Type::getInt32Ty(*Context), ExtractedIdx+NumElts);
-              
-            }
-            return true;
-          }
-        }
-      }
-    }
-  }
-  // TODO: Handle shufflevector here!
-  
-  return false;
-}
-
-/// CollectShuffleElements - We are building a shuffle of V, using RHS as the
-/// RHS of the shuffle instruction, if it is not null.  Return a shuffle mask
-/// that computes V and the LHS value of the shuffle.
-static Value *CollectShuffleElements(Value *V, std::vector<Constant*> &Mask,
-                                     Value *&RHS, LLVMContext *Context) {
-  assert(isa<VectorType>(V->getType()) && 
-         (RHS == 0 || V->getType() == RHS->getType()) &&
-         "Invalid shuffle!");
-  unsigned NumElts = cast<VectorType>(V->getType())->getNumElements();
-
-  if (isa<UndefValue>(V)) {
-    Mask.assign(NumElts, UndefValue::get(Type::getInt32Ty(*Context)));
-    return V;
-  } else if (isa<ConstantAggregateZero>(V)) {
-    Mask.assign(NumElts, ConstantInt::get(Type::getInt32Ty(*Context), 0));
-    return V;
-  } else if (InsertElementInst *IEI = dyn_cast<InsertElementInst>(V)) {
-    // If this is an insert of an extract from some other vector, include it.
-    Value *VecOp    = IEI->getOperand(0);
-    Value *ScalarOp = IEI->getOperand(1);
-    Value *IdxOp    = IEI->getOperand(2);
-    
-    if (ExtractElementInst *EI = dyn_cast<ExtractElementInst>(ScalarOp)) {
-      if (isa<ConstantInt>(EI->getOperand(1)) && isa<ConstantInt>(IdxOp) &&
-          EI->getOperand(0)->getType() == V->getType()) {
-        unsigned ExtractedIdx =
-          cast<ConstantInt>(EI->getOperand(1))->getZExtValue();
-        unsigned InsertedIdx = cast<ConstantInt>(IdxOp)->getZExtValue();
-        
-        // Either the extracted from or inserted into vector must be RHSVec,
-        // otherwise we'd end up with a shuffle of three inputs.
-        if (EI->getOperand(0) == RHS || RHS == 0) {
-          RHS = EI->getOperand(0);
-          Value *V = CollectShuffleElements(VecOp, Mask, RHS, Context);
-          Mask[InsertedIdx % NumElts] = 
-            ConstantInt::get(Type::getInt32Ty(*Context), NumElts+ExtractedIdx);
-          return V;
-        }
-        
-        if (VecOp == RHS) {
-          Value *V = CollectShuffleElements(EI->getOperand(0), Mask,
-                                            RHS, Context);
-          // Everything but the extracted element is replaced with the RHS.
-          for (unsigned i = 0; i != NumElts; ++i) {
-            if (i != InsertedIdx)
-              Mask[i] = ConstantInt::get(Type::getInt32Ty(*Context), NumElts+i);
-          }
-          return V;
-        }
-        
-        // If this insertelement is a chain that comes from exactly these two
-        // vectors, return the vector and the effective shuffle.
-        if (CollectSingleShuffleElements(IEI, EI->getOperand(0), RHS, Mask,
-                                         Context))
-          return EI->getOperand(0);
-        
-      }
-    }
-  }
-  // TODO: Handle shufflevector here!
-  
-  // Otherwise, can't do anything fancy.  Return an identity vector.
-  for (unsigned i = 0; i != NumElts; ++i)
-    Mask.push_back(ConstantInt::get(Type::getInt32Ty(*Context), i));
-  return V;
-}
-
-Instruction *InstCombiner::visitInsertElementInst(InsertElementInst &IE) {
-  Value *VecOp    = IE.getOperand(0);
-  Value *ScalarOp = IE.getOperand(1);
-  Value *IdxOp    = IE.getOperand(2);
-  
-  // Inserting an undef or into an undefined place, remove this.
-  if (isa<UndefValue>(ScalarOp) || isa<UndefValue>(IdxOp))
-    ReplaceInstUsesWith(IE, VecOp);
-  
-  // If the inserted element was extracted from some other vector, and if the 
-  // indexes are constant, try to turn this into a shufflevector operation.
-  if (ExtractElementInst *EI = dyn_cast<ExtractElementInst>(ScalarOp)) {
-    if (isa<ConstantInt>(EI->getOperand(1)) && isa<ConstantInt>(IdxOp) &&
-        EI->getOperand(0)->getType() == IE.getType()) {
-      unsigned NumVectorElts = IE.getType()->getNumElements();
-      unsigned ExtractedIdx =
-        cast<ConstantInt>(EI->getOperand(1))->getZExtValue();
-      unsigned InsertedIdx = cast<ConstantInt>(IdxOp)->getZExtValue();
-      
-      if (ExtractedIdx >= NumVectorElts) // Out of range extract.
-        return ReplaceInstUsesWith(IE, VecOp);
-      
-      if (InsertedIdx >= NumVectorElts)  // Out of range insert.
-        return ReplaceInstUsesWith(IE, UndefValue::get(IE.getType()));
-      
-      // If we are extracting a value from a vector, then inserting it right
-      // back into the same place, just use the input vector.
-      if (EI->getOperand(0) == VecOp && ExtractedIdx == InsertedIdx)
-        return ReplaceInstUsesWith(IE, VecOp);      
-      
-      // If this insertelement isn't used by some other insertelement, turn it
-      // (and any insertelements it points to), into one big shuffle.
-      if (!IE.hasOneUse() || !isa<InsertElementInst>(IE.use_back())) {
-        std::vector<Constant*> Mask;
-        Value *RHS = 0;
-        Value *LHS = CollectShuffleElements(&IE, Mask, RHS, Context);
-        if (RHS == 0) RHS = UndefValue::get(LHS->getType());
-        // We now have a shuffle of LHS, RHS, Mask.
-        return new ShuffleVectorInst(LHS, RHS,
-                                     ConstantVector::get(Mask));
-      }
-    }
-  }
-
-  unsigned VWidth = cast<VectorType>(VecOp->getType())->getNumElements();
-  APInt UndefElts(VWidth, 0);
-  APInt AllOnesEltMask(APInt::getAllOnesValue(VWidth));
-  if (SimplifyDemandedVectorElts(&IE, AllOnesEltMask, UndefElts))
-    return &IE;
-
-  return 0;
-}
-
-
-Instruction *InstCombiner::visitShuffleVectorInst(ShuffleVectorInst &SVI) {
-  Value *LHS = SVI.getOperand(0);
-  Value *RHS = SVI.getOperand(1);
-  std::vector<unsigned> Mask = getShuffleMask(&SVI);
-
-  bool MadeChange = false;
-
-  // Undefined shuffle mask -> undefined value.
-  if (isa<UndefValue>(SVI.getOperand(2)))
-    return ReplaceInstUsesWith(SVI, UndefValue::get(SVI.getType()));
-
-  unsigned VWidth = cast<VectorType>(SVI.getType())->getNumElements();
-
-  if (VWidth != cast<VectorType>(LHS->getType())->getNumElements())
-    return 0;
-
-  APInt UndefElts(VWidth, 0);
-  APInt AllOnesEltMask(APInt::getAllOnesValue(VWidth));
-  if (SimplifyDemandedVectorElts(&SVI, AllOnesEltMask, UndefElts)) {
-    LHS = SVI.getOperand(0);
-    RHS = SVI.getOperand(1);
-    MadeChange = true;
-  }
-  
-  // Canonicalize shuffle(x    ,x,mask) -> shuffle(x, undef,mask')
-  // Canonicalize shuffle(undef,x,mask) -> shuffle(x, undef,mask').
-  if (LHS == RHS || isa<UndefValue>(LHS)) {
-    if (isa<UndefValue>(LHS) && LHS == RHS) {
-      // shuffle(undef,undef,mask) -> undef.
-      return ReplaceInstUsesWith(SVI, LHS);
-    }
-    
-    // Remap any references to RHS to use LHS.
-    std::vector<Constant*> Elts;
-    for (unsigned i = 0, e = Mask.size(); i != e; ++i) {
-      if (Mask[i] >= 2*e)
-        Elts.push_back(UndefValue::get(Type::getInt32Ty(*Context)));
-      else {
-        if ((Mask[i] >= e && isa<UndefValue>(RHS)) ||
-            (Mask[i] <  e && isa<UndefValue>(LHS))) {
-          Mask[i] = 2*e;     // Turn into undef.
-          Elts.push_back(UndefValue::get(Type::getInt32Ty(*Context)));
-        } else {
-          Mask[i] = Mask[i] % e;  // Force to LHS.
-          Elts.push_back(ConstantInt::get(Type::getInt32Ty(*Context), Mask[i]));
-        }
-      }
-    }
-    SVI.setOperand(0, SVI.getOperand(1));
-    SVI.setOperand(1, UndefValue::get(RHS->getType()));
-    SVI.setOperand(2, ConstantVector::get(Elts));
-    LHS = SVI.getOperand(0);
-    RHS = SVI.getOperand(1);
-    MadeChange = true;
-  }
-  
-  // Analyze the shuffle, are the LHS or RHS and identity shuffles?
-  bool isLHSID = true, isRHSID = true;
-    
-  for (unsigned i = 0, e = Mask.size(); i != e; ++i) {
-    if (Mask[i] >= e*2) continue;  // Ignore undef values.
-    // Is this an identity shuffle of the LHS value?
-    isLHSID &= (Mask[i] == i);
-      
-    // Is this an identity shuffle of the RHS value?
-    isRHSID &= (Mask[i]-e == i);
-  }
-
-  // Eliminate identity shuffles.
-  if (isLHSID) return ReplaceInstUsesWith(SVI, LHS);
-  if (isRHSID) return ReplaceInstUsesWith(SVI, RHS);
-  
-  // If the LHS is a shufflevector itself, see if we can combine it with this
-  // one without producing an unusual shuffle.  Here we are really conservative:
-  // we are absolutely afraid of producing a shuffle mask not in the input
-  // program, because the code gen may not be smart enough to turn a merged
-  // shuffle into two specific shuffles: it may produce worse code.  As such,
-  // we only merge two shuffles if the result is one of the two input shuffle
-  // masks.  In this case, merging the shuffles just removes one instruction,
-  // which we know is safe.  This is good for things like turning:
-  // (splat(splat)) -> splat.
-  if (ShuffleVectorInst *LHSSVI = dyn_cast<ShuffleVectorInst>(LHS)) {
-    if (isa<UndefValue>(RHS)) {
-      std::vector<unsigned> LHSMask = getShuffleMask(LHSSVI);
-
-      if (LHSMask.size() == Mask.size()) {
-        std::vector<unsigned> NewMask;
-        for (unsigned i = 0, e = Mask.size(); i != e; ++i)
-          if (Mask[i] >= e)
-            NewMask.push_back(2*e);
-          else
-            NewMask.push_back(LHSMask[Mask[i]]);
-      
-        // If the result mask is equal to the src shuffle or this
-        // shuffle mask, do the replacement.
-        if (NewMask == LHSMask || NewMask == Mask) {
-          unsigned LHSInNElts =
-            cast<VectorType>(LHSSVI->getOperand(0)->getType())->
-            getNumElements();
-          std::vector<Constant*> Elts;
-          for (unsigned i = 0, e = NewMask.size(); i != e; ++i) {
-            if (NewMask[i] >= LHSInNElts*2) {
-              Elts.push_back(UndefValue::get(Type::getInt32Ty(*Context)));
-            } else {
-              Elts.push_back(ConstantInt::get(Type::getInt32Ty(*Context),
-                                              NewMask[i]));
-            }
-          }
-          return new ShuffleVectorInst(LHSSVI->getOperand(0),
-                                       LHSSVI->getOperand(1),
-                                       ConstantVector::get(Elts));
-        }
-      }
-    }
-  }
-
-  return MadeChange ? &SVI : 0;
-}
-
-
-
-
-/// TryToSinkInstruction - Try to move the specified instruction from its
-/// current block into the beginning of DestBlock, which can only happen if it's
-/// safe to move the instruction past all of the instructions between it and the
-/// end of its block.
-static bool TryToSinkInstruction(Instruction *I, BasicBlock *DestBlock) {
-  assert(I->hasOneUse() && "Invariants didn't hold!");
-
-  // Cannot move control-flow-involving, volatile loads, vaarg, etc.
-  if (isa<PHINode>(I) || I->mayHaveSideEffects() || isa<TerminatorInst>(I))
-    return false;
-
-  // Do not sink alloca instructions out of the entry block.
-  if (isa<AllocaInst>(I) && I->getParent() ==
-        &DestBlock->getParent()->getEntryBlock())
-    return false;
-
-  // We can only sink load instructions if there is nothing between the load and
-  // the end of block that could change the value.
-  if (I->mayReadFromMemory()) {
-    for (BasicBlock::iterator Scan = I, E = I->getParent()->end();
-         Scan != E; ++Scan)
-      if (Scan->mayWriteToMemory())
-        return false;
-  }
-
-  BasicBlock::iterator InsertPos = DestBlock->getFirstNonPHI();
-
-  CopyPrecedingStopPoint(I, InsertPos);
-  I->moveBefore(InsertPos);
-  ++NumSunkInst;
-  return true;
-}
-
-
-/// AddReachableCodeToWorklist - Walk the function in depth-first order, adding
-/// all reachable code to the worklist.
-///
-/// This has a couple of tricks to make the code faster and more powerful.  In
-/// particular, we constant fold and DCE instructions as we go, to avoid adding
-/// them to the worklist (this significantly speeds up instcombine on code where
-/// many instructions are dead or constant).  Additionally, if we find a branch
-/// whose condition is a known constant, we only visit the reachable successors.
-///
-static bool AddReachableCodeToWorklist(BasicBlock *BB, 
-                                       SmallPtrSet<BasicBlock*, 64> &Visited,
-                                       InstCombiner &IC,
-                                       const TargetData *TD) {
-  bool MadeIRChange = false;
-  SmallVector<BasicBlock*, 256> Worklist;
-  Worklist.push_back(BB);
-  
-  std::vector<Instruction*> InstrsForInstCombineWorklist;
-  InstrsForInstCombineWorklist.reserve(128);
-
-  SmallPtrSet<ConstantExpr*, 64> FoldedConstants;
-  
-  while (!Worklist.empty()) {
-    BB = Worklist.back();
-    Worklist.pop_back();
-    
-    // We have now visited this block!  If we've already been here, ignore it.
-    if (!Visited.insert(BB)) continue;
-
-    for (BasicBlock::iterator BBI = BB->begin(), E = BB->end(); BBI != E; ) {
-      Instruction *Inst = BBI++;
-      
-      // DCE instruction if trivially dead.
-      if (isInstructionTriviallyDead(Inst)) {
-        ++NumDeadInst;
-        DEBUG(errs() << "IC: DCE: " << *Inst << '\n');
-        Inst->eraseFromParent();
-        continue;
-      }
-      
-      // ConstantProp instruction if trivially constant.
-      if (!Inst->use_empty() && isa<Constant>(Inst->getOperand(0)))
-        if (Constant *C = ConstantFoldInstruction(Inst, TD)) {
-          DEBUG(errs() << "IC: ConstFold to: " << *C << " from: "
-                       << *Inst << '\n');
-          Inst->replaceAllUsesWith(C);
-          ++NumConstProp;
-          Inst->eraseFromParent();
-          continue;
-        }
-      
-      
-      
-      if (TD) {
-        // See if we can constant fold its operands.
-        for (User::op_iterator i = Inst->op_begin(), e = Inst->op_end();
-             i != e; ++i) {
-          ConstantExpr *CE = dyn_cast<ConstantExpr>(i);
-          if (CE == 0) continue;
-          
-          // If we already folded this constant, don't try again.
-          if (!FoldedConstants.insert(CE))
-            continue;
-          
-          Constant *NewC = ConstantFoldConstantExpression(CE, TD);
-          if (NewC && NewC != CE) {
-            *i = NewC;
-            MadeIRChange = true;
-          }
-        }
-      }
-      
-
-      InstrsForInstCombineWorklist.push_back(Inst);
-    }
-
-    // Recursively visit successors.  If this is a branch or switch on a
-    // constant, only visit the reachable successor.
-    TerminatorInst *TI = BB->getTerminator();
-    if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
-      if (BI->isConditional() && isa<ConstantInt>(BI->getCondition())) {
-        bool CondVal = cast<ConstantInt>(BI->getCondition())->getZExtValue();
-        BasicBlock *ReachableBB = BI->getSuccessor(!CondVal);
-        Worklist.push_back(ReachableBB);
-        continue;
-      }
-    } else if (SwitchInst *SI = dyn_cast<SwitchInst>(TI)) {
-      if (ConstantInt *Cond = dyn_cast<ConstantInt>(SI->getCondition())) {
-        // See if this is an explicit destination.
-        for (unsigned i = 1, e = SI->getNumSuccessors(); i != e; ++i)
-          if (SI->getCaseValue(i) == Cond) {
-            BasicBlock *ReachableBB = SI->getSuccessor(i);
-            Worklist.push_back(ReachableBB);
-            continue;
-          }
-        
-        // Otherwise it is the default destination.
-        Worklist.push_back(SI->getSuccessor(0));
-        continue;
-      }
-    }
-    
-    for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
-      Worklist.push_back(TI->getSuccessor(i));
-  }
-  
-  // Once we've found all of the instructions to add to instcombine's worklist,
-  // add them in reverse order.  This way instcombine will visit from the top
-  // of the function down.  This jives well with the way that it adds all uses
-  // of instructions to the worklist after doing a transformation, thus avoiding
-  // some N^2 behavior in pathological cases.
-  IC.Worklist.AddInitialGroup(&InstrsForInstCombineWorklist[0],
-                              InstrsForInstCombineWorklist.size());
-  
-  return MadeIRChange;
-}
-
-bool InstCombiner::DoOneIteration(Function &F, unsigned Iteration) {
-  MadeIRChange = false;
-  
-  DEBUG(errs() << "\n\nINSTCOMBINE ITERATION #" << Iteration << " on "
-        << F.getNameStr() << "\n");
-
-  {
-    // Do a depth-first traversal of the function, populate the worklist with
-    // the reachable instructions.  Ignore blocks that are not reachable.  Keep
-    // track of which blocks we visit.
-    SmallPtrSet<BasicBlock*, 64> Visited;
-    MadeIRChange |= AddReachableCodeToWorklist(F.begin(), Visited, *this, TD);
-
-    // Do a quick scan over the function.  If we find any blocks that are
-    // unreachable, remove any instructions inside of them.  This prevents
-    // the instcombine code from having to deal with some bad special cases.
-    for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
-      if (!Visited.count(BB)) {
-        Instruction *Term = BB->getTerminator();
-        while (Term != BB->begin()) {   // Remove instrs bottom-up
-          BasicBlock::iterator I = Term; --I;
-
-          DEBUG(errs() << "IC: DCE: " << *I << '\n');
-          // A debug intrinsic shouldn't force another iteration if we weren't
-          // going to do one without it.
-          if (!isa<DbgInfoIntrinsic>(I)) {
-            ++NumDeadInst;
-            MadeIRChange = true;
-          }
-
-          // If I is not void type then replaceAllUsesWith undef.
-          // This allows ValueHandlers and custom metadata to adjust itself.
-          if (!I->getType()->isVoidTy())
-            I->replaceAllUsesWith(UndefValue::get(I->getType()));
-          I->eraseFromParent();
-        }
-      }
-  }
-
-  while (!Worklist.isEmpty()) {
-    Instruction *I = Worklist.RemoveOne();
-    if (I == 0) continue;  // skip null values.
-
-    // Check to see if we can DCE the instruction.
-    if (isInstructionTriviallyDead(I)) {
-      DEBUG(errs() << "IC: DCE: " << *I << '\n');
-      EraseInstFromFunction(*I);
-      ++NumDeadInst;
-      MadeIRChange = true;
-      continue;
-    }
-
-    // Instruction isn't dead, see if we can constant propagate it.
-    if (!I->use_empty() && isa<Constant>(I->getOperand(0)))
-      if (Constant *C = ConstantFoldInstruction(I, TD)) {
-        DEBUG(errs() << "IC: ConstFold to: " << *C << " from: " << *I << '\n');
-
-        // Add operands to the worklist.
-        ReplaceInstUsesWith(*I, C);
-        ++NumConstProp;
-        EraseInstFromFunction(*I);
-        MadeIRChange = true;
-        continue;
-      }
-
-    // See if we can trivially sink this instruction to a successor basic block.
-    if (I->hasOneUse()) {
-      BasicBlock *BB = I->getParent();
-      Instruction *UserInst = cast<Instruction>(I->use_back());
-      BasicBlock *UserParent;
-      
-      // Get the block the use occurs in.
-      if (PHINode *PN = dyn_cast<PHINode>(UserInst))
-        UserParent = PN->getIncomingBlock(I->use_begin().getUse());
-      else
-        UserParent = UserInst->getParent();
-      
-      if (UserParent != BB) {
-        bool UserIsSuccessor = false;
-        // See if the user is one of our successors.
-        for (succ_iterator SI = succ_begin(BB), E = succ_end(BB); SI != E; ++SI)
-          if (*SI == UserParent) {
-            UserIsSuccessor = true;
-            break;
-          }
-
-        // If the user is one of our immediate successors, and if that successor
-        // only has us as a predecessors (we'd have to split the critical edge
-        // otherwise), we can keep going.
-        if (UserIsSuccessor && UserParent->getSinglePredecessor())
-          // Okay, the CFG is simple enough, try to sink this instruction.
-          MadeIRChange |= TryToSinkInstruction(I, UserParent);
-      }
-    }
-
-    // Now that we have an instruction, try combining it to simplify it.
-    Builder->SetInsertPoint(I->getParent(), I);
-    
-#ifndef NDEBUG
-    std::string OrigI;
-#endif
-    DEBUG(raw_string_ostream SS(OrigI); I->print(SS); OrigI = SS.str(););
-    DEBUG(errs() << "IC: Visiting: " << OrigI << '\n');
-
-    if (Instruction *Result = visit(*I)) {
-      ++NumCombined;
-      // Should we replace the old instruction with a new one?
-      if (Result != I) {
-        DEBUG(errs() << "IC: Old = " << *I << '\n'
-                     << "    New = " << *Result << '\n');
-
-        // Everything uses the new instruction now.
-        I->replaceAllUsesWith(Result);
-
-        // Push the new instruction and any users onto the worklist.
-        Worklist.Add(Result);
-        Worklist.AddUsersToWorkList(*Result);
-
-        // Move the name to the new instruction first.
-        Result->takeName(I);
-
-        // Insert the new instruction into the basic block...
-        BasicBlock *InstParent = I->getParent();
-        BasicBlock::iterator InsertPos = I;
-
-        if (!isa<PHINode>(Result))        // If combining a PHI, don't insert
-          while (isa<PHINode>(InsertPos)) // middle of a block of PHIs.
-            ++InsertPos;
-
-        InstParent->getInstList().insert(InsertPos, Result);
-
-        EraseInstFromFunction(*I);
-      } else {
-#ifndef NDEBUG
-        DEBUG(errs() << "IC: Mod = " << OrigI << '\n'
-                     << "    New = " << *I << '\n');
-#endif
-
-        // If the instruction was modified, it's possible that it is now dead.
-        // if so, remove it.
-        if (isInstructionTriviallyDead(I)) {
-          EraseInstFromFunction(*I);
-        } else {
-          Worklist.Add(I);
-          Worklist.AddUsersToWorkList(*I);
-        }
-      }
-      MadeIRChange = true;
-    }
-  }
-
-  Worklist.Zap();
-  return MadeIRChange;
-}
-
-
-bool InstCombiner::runOnFunction(Function &F) {
-  MustPreserveLCSSA = mustPreserveAnalysisID(LCSSAID);
-  Context = &F.getContext();
-  TD = getAnalysisIfAvailable<TargetData>();
-
-  
-  /// Builder - This is an IRBuilder that automatically inserts new
-  /// instructions into the worklist when they are created.
-  IRBuilder<true, TargetFolder, InstCombineIRInserter> 
-    TheBuilder(F.getContext(), TargetFolder(TD),
-               InstCombineIRInserter(Worklist));
-  Builder = &TheBuilder;
-  
-  bool EverMadeChange = false;
-
-  // Iterate while there is work to do.
-  unsigned Iteration = 0;
-  while (DoOneIteration(F, Iteration++))
-    EverMadeChange = true;
-  
-  Builder = 0;
-  return EverMadeChange;
-}
-
-FunctionPass *llvm::createInstructionCombiningPass() {
-  return new InstCombiner();
-}