SwitchInst refactoring.

The purpose of refactoring is to hide operand roles from SwitchInst user (programmer). If you want to play with operands directly, probably you will need lower level methods than SwitchInst ones (TerminatorInst or may be User). After this patch we can reorganize SwitchInst operands and successors as we want.

What was done:

1. Changed semantics of index inside the getCaseValue method:
getCaseValue(0) means "get first case", not a condition. Use getCondition() if you want to resolve the condition. I propose don't mix SwitchInst case indexing with low level indexing (TI successors indexing, User's operands indexing), since it may be dangerous.
2. By the same reason findCaseValue(ConstantInt*) returns actual number of case value. 0 means first case, not default. If there is no case with given value, ErrorIndex will returned.
3. Added getCaseSuccessor method. I propose to avoid usage of TerminatorInst::getSuccessor if you want to resolve case successor BB. Use getCaseSuccessor instead, since internal SwitchInst organization of operands/successors is hidden and may be changed in any moment.
4. Added resolveSuccessorIndex and resolveCaseIndex. The main purpose of these methods is to see how case successors are really mapped in TerminatorInst.
4.1 "resolveSuccessorIndex" was created if you need to level down from SwitchInst to TerminatorInst. It returns TerminatorInst's successor index for given case successor.
4.2 "resolveCaseIndex" converts low level successors index to case index that curresponds to the given successor.

Note: There are also related compatability fix patches for dragonegg, klee, llvm-gcc-4.0, llvm-gcc-4.2, safecode, clang.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149481 91177308-0d34-0410-b5e6-96231b3b80d8

26 files changed, 204 insertions, 139 deletions

diff --git a/include/llvm/Analysis/CFGPrinter.h b/include/llvm/Analysis/CFGPrinter.h
index 8f7ebcb0f9..2cde838fc0 100644
--- a/include/llvm/Analysis/CFGPrinter.h
+++ b/include/llvm/Analysis/CFGPrinter.h
@@ -95,7 +95,8 @@ struct DOTGraphTraits<const Function*> : public DefaultDOTGraphTraits {
       
       std::string Str;
       raw_string_ostream OS(Str);
-      OS << SI->getCaseValue(SuccNo)->getValue();
+      unsigned Case = SI->resolveCaseIndex(SuccNo);
+      OS << SI->getCaseValue(Case)->getValue();
       return OS.str();
     }    
     return "";
diff --git a/include/llvm/Instructions.h b/include/llvm/Instructions.h
index c27c6fa097..bb6a6ffdd8 100644
--- a/include/llvm/Instructions.h
+++ b/include/llvm/Instructions.h
@@ -24,6 +24,7 @@
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Support/ErrorHandling.h"
 #include <iterator>
+#include <limits.h>
 
 namespace llvm {
 
@@ -2467,6 +2468,9 @@ class SwitchInst : public TerminatorInst {
 protected:
   virtual SwitchInst *clone_impl() const;
 public:
+
+  enum { ErrorIndex = UINT_MAX };
+
   static SwitchInst *Create(Value *Value, BasicBlock *Default,
                             unsigned NumCases, Instruction *InsertBefore = 0) {
     return new SwitchInst(Value, Default, NumCases, InsertBefore);
@@ -2488,34 +2492,62 @@ public:
     return cast<BasicBlock>(getOperand(1));
   }
 
-  /// getNumCases - return the number of 'cases' in this switch instruction.
-  /// Note that case #0 is always the default case.
+  void setDefaultDest(BasicBlock *DefaultCase) {
+    setOperand(1, reinterpret_cast<Value*>(DefaultCase));
+  }
+
+  /// getNumCases - return the number of 'cases' in this switch instruction,
+  /// except the default case
   unsigned getNumCases() const {
-    return getNumOperands()/2;
+    return getNumOperands()/2 - 1;
   }
 
-  /// getCaseValue - Return the specified case value.  Note that case #0, the
-  /// default destination, does not have a case value.
+  /// getCaseValue - Return the specified case value. Note that case #0, means
+  /// first case, not a default case.
   ConstantInt *getCaseValue(unsigned i) {
-    assert(i && i < getNumCases() && "Illegal case value to get!");
-    return getSuccessorValue(i);
+    assert(i < getNumCases() && "Illegal case value to get!");
+    return reinterpret_cast<ConstantInt*>(getOperand(2 + i*2));
   }
 
-  /// getCaseValue - Return the specified case value.  Note that case #0, the
-  /// default destination, does not have a case value.
+  /// getCaseValue - Return the specified case value. Note that case #0, means
+  /// first case, not a default case.
   const ConstantInt *getCaseValue(unsigned i) const {
-    assert(i && i < getNumCases() && "Illegal case value to get!");
-    return getSuccessorValue(i);
+    assert(i < getNumCases() && "Illegal case value to get!");
+    return reinterpret_cast<const ConstantInt*>(getOperand(2 + i*2));
+  }
+
+  // setSuccessorValue - Updates the value associated with the specified
+  // case.
+  void setCaseValue(unsigned i, ConstantInt *CaseValue) {
+    assert(i < getNumCases() && "Case index # out of range!");
+    setOperand(2 + i*2, reinterpret_cast<Value*>(CaseValue));
   }
 
   /// findCaseValue - Search all of the case values for the specified constant.
   /// If it is explicitly handled, return the case number of it, otherwise
-  /// return 0 to indicate that it is handled by the default handler.
+  /// return ErrorIndex to indicate that it is handled by the default handler.
   unsigned findCaseValue(const ConstantInt *C) const {
-    for (unsigned i = 1, e = getNumCases(); i != e; ++i)
+    for (unsigned i = 0, e = getNumCases(); i != e; ++i)
       if (getCaseValue(i) == C)
         return i;
-    return 0;
+    return ErrorIndex;
+  }
+  
+  /// resolveSuccessorIndex - Converts case index to index of its successor
+  /// index in TerminatorInst successors collection.
+  /// If CaseIndex == ErrorIndex, "default" successor will returned then. 
+  unsigned resolveSuccessorIndex(unsigned CaseIndex) const {
+    assert((CaseIndex == ErrorIndex || CaseIndex < getNumCases()) &&
+           "Case index # out of range!");
+    return CaseIndex != ErrorIndex ? CaseIndex + 1 : 0;
+  }
+  
+  /// resolveCaseIndex - Converts index of successor in TerminatorInst
+  /// collection to index of case that corresponds to this successor.
+  unsigned resolveCaseIndex(unsigned SuccessorIndex) const {
+    assert(SuccessorIndex < getNumSuccessors() &&
+           "Successor index # out of range!");    
+    return SuccessorIndex != 0 ? SuccessorIndex - 1 : ErrorIndex; 
   }
 
   /// findCaseDest - Finds the unique case value for a given successor. Returns
@@ -2524,8 +2556,8 @@ public:
     if (BB == getDefaultDest()) return NULL;
 
     ConstantInt *CI = NULL;
-    for (unsigned i = 1, e = getNumCases(); i != e; ++i) {
-      if (getSuccessor(i) == BB) {
+    for (unsigned i = 0, e = getNumCases(); i != e; ++i) {
+      if (getSuccessor(i + 1) == BB) {
         if (CI) return NULL;   // Multiple cases lead to BB.
         else CI = getCaseValue(i);
       }
@@ -2537,9 +2569,8 @@ public:
   ///
   void addCase(ConstantInt *OnVal, BasicBlock *Dest);
 
-  /// removeCase - This method removes the specified successor from the switch
-  /// instruction.  Note that this cannot be used to remove the default
-  /// destination (successor #0). Also note that this operation may reorder the
+  /// removeCase - This method removes the specified case and its successor
+  /// from the switch instruction. Note that this operation may reorder the
   /// remaining cases at index idx and above.
   ///
   void removeCase(unsigned idx);
@@ -2554,6 +2585,22 @@ public:
     setOperand(idx*2+1, (Value*)NewSucc);
   }
 
+  /// Resolves successor for idx-th case.
+  /// Use getCaseSuccessor instead of TerminatorInst::getSuccessor,
+  /// since internal SwitchInst organization of operands/successors is
+  /// hidden and may be changed in any moment.
+  BasicBlock *getCaseSuccessor(unsigned idx) const {
+    return getSuccessor(resolveSuccessorIndex(idx));
+  }
+
+  /// Set new successor for idx-th case.
+  /// Use setCaseSuccessor instead of TerminatorInst::setSuccessor,
+  /// since internal SwitchInst organization of operands/successors is
+  /// hidden and may be changed in any moment.
+  void setCaseSuccessor(unsigned idx, BasicBlock *NewSucc) {
+    setSuccessor(resolveSuccessorIndex(idx), NewSucc);
+  }
+
   // getSuccessorValue - Return the value associated with the specified
   // successor.
   ConstantInt *getSuccessorValue(unsigned idx) const {
diff --git a/lib/Analysis/LazyValueInfo.cpp b/lib/Analysis/LazyValueInfo.cpp
index 950d4a6537..e1c099e435 100644
--- a/lib/Analysis/LazyValueInfo.cpp
+++ b/lib/Analysis/LazyValueInfo.cpp
@@ -854,8 +854,8 @@ bool LazyValueInfoCache::getEdgeValue(Value *Val, BasicBlock *BBFrom,
       // BBFrom to BBTo.
       unsigned NumEdges = 0;
       ConstantInt *EdgeVal = 0;
-      for (unsigned i = 1, e = SI->getNumSuccessors(); i != e; ++i) {
-        if (SI->getSuccessor(i) != BBTo) continue;
+      for (unsigned i = 0, e = SI->getNumCases(); i != e; ++i) {
+        if (SI->getCaseSuccessor(i) != BBTo) continue;
         if (NumEdges++) break;
         EdgeVal = SI->getCaseValue(i);
       }
diff --git a/lib/Analysis/SparsePropagation.cpp b/lib/Analysis/SparsePropagation.cpp
index 035bceaf27..0c7d05f91d 100644
--- a/lib/Analysis/SparsePropagation.cpp
+++ b/lib/Analysis/SparsePropagation.cpp
@@ -195,7 +195,8 @@ void SparseSolver::getFeasibleSuccessors(TerminatorInst &TI,
     return;
   }
   
-  Succs[SI.findCaseValue(cast<ConstantInt>(C))] = true;
+  unsigned CCase = SI.findCaseValue(cast<ConstantInt>(C));
+  Succs[SI.resolveSuccessorIndex(CCase)] = true;
 }
 
 
diff --git a/lib/Bitcode/Writer/BitcodeWriter.cpp b/lib/Bitcode/Writer/BitcodeWriter.cpp
index d58f7cf73d..81d5720126 100644
--- a/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -1162,10 +1162,17 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
     }
     break;
   case Instruction::Switch:
-    Code = bitc::FUNC_CODE_INST_SWITCH;
-    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
-    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
-      Vals.push_back(VE.getValueID(I.getOperand(i)));
+    {
+      Code = bitc::FUNC_CODE_INST_SWITCH;
+      SwitchInst &SI = cast<SwitchInst>(I);
+      Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
+      Vals.push_back(VE.getValueID(SI.getCondition()));
+      Vals.push_back(VE.getValueID(SI.getDefaultDest()));
+      for (unsigned i = 0, e = SI.getNumCases(); i != e; ++i) {
+        Vals.push_back(VE.getValueID(SI.getCaseValue(i)));
+        Vals.push_back(VE.getValueID(SI.getCaseSuccessor(i)));
+      }
+    }
     break;
   case Instruction::IndirectBr:
     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 8286f57914..d46d8e41bb 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -2209,7 +2209,7 @@ bool SelectionDAGBuilder::handleBTSplitSwitchCase(CaseRec& CR,
 
   CaseRange LHSR(CR.Range.first, Pivot);
   CaseRange RHSR(Pivot, CR.Range.second);
-  Constant *C = Pivot->Low;
+  const Constant *C = Pivot->Low;
   MachineBasicBlock *FalseBB = 0, *TrueBB = 0;
 
   // We know that we branch to the LHS if the Value being switched on is
@@ -2402,14 +2402,14 @@ size_t SelectionDAGBuilder::Clusterify(CaseVector& Cases,
 
   BranchProbabilityInfo *BPI = FuncInfo.BPI;
   // Start with "simple" cases
-  for (size_t i = 1; i < SI.getNumSuccessors(); ++i) {
-    BasicBlock *SuccBB = SI.getSuccessor(i);
+  for (size_t i = 0; i < SI.getNumCases(); ++i) {
+    BasicBlock *SuccBB = SI.getCaseSuccessor(i);
     MachineBasicBlock *SMBB = FuncInfo.MBBMap[SuccBB];
 
     uint32_t ExtraWeight = BPI ? BPI->getEdgeWeight(SI.getParent(), SuccBB) : 0;
 
-    Cases.push_back(Case(SI.getSuccessorValue(i),
-                         SI.getSuccessorValue(i),
+    Cases.push_back(Case(SI.getCaseValue(i),
+                         SI.getCaseValue(i),
                          SMBB, ExtraWeight));
   }
   std::sort(Cases.begin(), Cases.end(), CaseCmp());
@@ -2476,7 +2476,7 @@ void SelectionDAGBuilder::visitSwitch(const SwitchInst &SI) {
 
   // If there is only the default destination, branch to it if it is not the
   // next basic block.  Otherwise, just fall through.
-  if (SI.getNumCases() == 1) {
+  if (!SI.getNumCases()) {
     // Update machine-CFG edges.
 
     // If this is not a fall-through branch, emit the branch.
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
index 36bdf38c48..62c55053e1 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
@@ -130,13 +130,13 @@ private:
   /// Case - A struct to record the Value for a switch case, and the
   /// case's target basic block.
   struct Case {
-    Constant* Low;
-    Constant* High;
+    const Constant *Low;
+    const Constant *High;
     MachineBasicBlock* BB;
     uint32_t ExtraWeight;
 
     Case() : Low(0), High(0), BB(0), ExtraWeight(0) { }
-    Case(Constant* low, Constant* high, MachineBasicBlock* bb,
+    Case(const Constant *low, const Constant *high, MachineBasicBlock *bb,
          uint32_t extraweight) : Low(low), High(high), BB(bb),
          ExtraWeight(extraweight) { }
 
diff --git a/lib/ExecutionEngine/Interpreter/Execution.cpp b/lib/ExecutionEngine/Interpreter/Execution.cpp
index d8065e1650..1af40ddc53 100644
--- a/lib/ExecutionEngine/Interpreter/Execution.cpp
+++ b/lib/ExecutionEngine/Interpreter/Execution.cpp
@@ -670,10 +670,10 @@ void Interpreter::visitSwitchInst(SwitchInst &I) {
   BasicBlock *Dest = 0;
   unsigned NumCases = I.getNumCases();
   // Skip the first item since that's the default case.
-  for (unsigned i = 1; i < NumCases; ++i) {
+  for (unsigned i = 0; i < NumCases; ++i) {
     GenericValue CaseVal = getOperandValue(I.getCaseValue(i), SF);
     if (executeICMP_EQ(CondVal, CaseVal, ElTy).IntVal != 0) {
-      Dest = cast<BasicBlock>(I.getSuccessor(i));
+      Dest = cast<BasicBlock>(I.getCaseSuccessor(i));
       break;
     }
   }
diff --git a/lib/Target/CBackend/CBackend.cpp b/lib/Target/CBackend/CBackend.cpp
index 8c83bc349a..b841a5c8d6 100644
--- a/lib/Target/CBackend/CBackend.cpp
+++ b/lib/Target/CBackend/CBackend.cpp
@@ -2449,9 +2449,9 @@ void CWriter::visitSwitchInst(SwitchInst &SI) {
 
   unsigned NumCases = SI.getNumCases();
   // Skip the first item since that's the default case.
-  for (unsigned i = 1; i < NumCases; ++i) {
+  for (unsigned i = 0; i < NumCases; ++i) {
     ConstantInt* CaseVal = SI.getCaseValue(i);
-    BasicBlock* Succ = SI.getSuccessor(i);
+    BasicBlock* Succ = SI.getCaseSuccessor(i);
     Out << "  case ";
     writeOperand(CaseVal);
     Out << ":\n";
diff --git a/lib/Target/CppBackend/CPPBackend.cpp b/lib/Target/CppBackend/CPPBackend.cpp
index de73a72ac4..956afcc317 100644
--- a/lib/Target/CppBackend/CPPBackend.cpp
+++ b/lib/Target/CppBackend/CPPBackend.cpp
@@ -1115,9 +1115,9 @@ void CppWriter::printInstruction(const Instruction *I,
         << SI->getNumCases() << ", " << bbname << ");";
     nl(Out);
     unsigned NumCases = SI->getNumCases();
-    for (unsigned i = 1; i < NumCases; ++i) {
+    for (unsigned i = 0; i < NumCases; ++i) {
       const ConstantInt* CaseVal = SI->getCaseValue(i);
-      const BasicBlock* BB = SI->getSuccessor(i);
+      const BasicBlock *BB = SI->getCaseSuccessor(i);
       Out << iName << "->addCase("
           << getOpName(CaseVal) << ", "
           << getOpName(BB) << ");";
diff --git a/lib/Transforms/IPO/GlobalOpt.cpp b/lib/Transforms/IPO/GlobalOpt.cpp
index 2f963d1583..884d883618 100644
--- a/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/lib/Transforms/IPO/GlobalOpt.cpp
@@ -2455,7 +2455,8 @@ static bool EvaluateFunction(Function *F, Constant *&RetVal,
         ConstantInt *Val =
           dyn_cast<ConstantInt>(getVal(Values, SI->getCondition()));
         if (!Val) return false;  // Cannot determine.
-        NewBB = SI->getSuccessor(SI->findCaseValue(Val));
+        unsigned ValTISucc = SI->resolveSuccessorIndex(SI->findCaseValue(Val));
+        NewBB = SI->getSuccessor(ValTISucc);
       } else if (IndirectBrInst *IBI = dyn_cast<IndirectBrInst>(CurInst)) {
         Value *Val = getVal(Values, IBI->getAddress())->stripPointerCasts();
         if (BlockAddress *BA = dyn_cast<BlockAddress>(Val))
diff --git a/lib/Transforms/InstCombine/InstructionCombining.cpp b/lib/Transforms/InstCombine/InstructionCombining.cpp
index 64ed817e75..0294d2a5ac 100644
--- a/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -1251,13 +1251,13 @@ Instruction *InstCombiner::visitSwitchInst(SwitchInst &SI) {
         // change 'switch (X+4) case 1:' into 'switch (X) case -3'
         unsigned NumCases = SI.getNumCases();
         // Skip the first item since that's the default case.
-        for (unsigned i = 1; i < NumCases; ++i) {
+        for (unsigned i = 0; i < NumCases; ++i) {
           ConstantInt* CaseVal = SI.getCaseValue(i);
           Constant* NewCaseVal = ConstantExpr::getSub(cast<Constant>(CaseVal),
                                                       AddRHS);
           assert(isa<ConstantInt>(NewCaseVal) &&
                  "Result of expression should be constant");
-          SI.setSuccessorValue(i, cast<ConstantInt>(NewCaseVal));
+          SI.setCaseValue(i, cast<ConstantInt>(NewCaseVal));
         }
         SI.setCondition(I->getOperand(0));
         Worklist.Add(I);
@@ -1877,15 +1877,15 @@ static bool AddReachableCodeToWorklist(BasicBlock *BB,
     } 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)
+        for (unsigned i = 0, e = SI->getNumCases(); i != e; ++i)
           if (SI->getCaseValue(i) == Cond) {
-            BasicBlock *ReachableBB = SI->getSuccessor(i);
+            BasicBlock *ReachableBB = SI->getCaseSuccessor(i);
             Worklist.push_back(ReachableBB);
             continue;
           }
         
         // Otherwise it is the default destination.
-        Worklist.push_back(SI->getSuccessor(0));
+        Worklist.push_back(SI->getDefaultDest());
         continue;
       }
     }
diff --git a/lib/Transforms/Scalar/GVN.cpp b/lib/Transforms/Scalar/GVN.cpp
index d39ef3d688..bdcbfb07d6 100644
--- a/lib/Transforms/Scalar/GVN.cpp
+++ b/lib/Transforms/Scalar/GVN.cpp
@@ -2085,8 +2085,8 @@ bool GVN::processInstruction(Instruction *I) {
     Value *SwitchCond = SI->getCondition();
     BasicBlock *Parent = SI->getParent();
     bool Changed = false;
-    for (unsigned i = 1, e = SI->getNumCases(); i != e; ++i) {
-      BasicBlock *Dst = SI->getSuccessor(i);
+    for (unsigned i = 0, e = SI->getNumCases(); i != e; ++i) {
+      BasicBlock *Dst = SI->getCaseSuccessor(i);
       if (isOnlyReachableViaThisEdge(Parent, Dst, DT))
         Changed |= propagateEquality(SwitchCond, SI->getCaseValue(i), Dst);
     }
diff --git a/lib/Transforms/Scalar/JumpThreading.cpp b/lib/Transforms/Scalar/JumpThreading.cpp
index c78db3fc3e..fa25a8fcd7 100644
--- a/lib/Transforms/Scalar/JumpThreading.cpp
+++ b/lib/Transforms/Scalar/JumpThreading.cpp
@@ -1086,9 +1086,10 @@ bool JumpThreading::ProcessThreadableEdges(Value *Cond, BasicBlock *BB,
       DestBB = 0;
     else if (BranchInst *BI = dyn_cast<BranchInst>(BB->getTerminator()))
       DestBB = BI->getSuccessor(cast<ConstantInt>(Val)->isZero());
-    else if (SwitchInst *SI = dyn_cast<SwitchInst>(BB->getTerminator()))
-      DestBB = SI->getSuccessor(SI->findCaseValue(cast<ConstantInt>(Val)));
-    else {
+    else if (SwitchInst *SI = dyn_cast<SwitchInst>(BB->getTerminator())) {
+      unsigned ValCase = SI->findCaseValue(cast<ConstantInt>(Val));
+      DestBB = SI->getSuccessor(SI->resolveSuccessorIndex(ValCase));
+    } else {
       assert(isa<IndirectBrInst>(BB->getTerminator())
               && "Unexpected terminator");
       DestBB = cast<BlockAddress>(Val)->getBasicBlock();
diff --git a/lib/Transforms/Scalar/LoopUnswitch.cpp b/lib/Transforms/Scalar/LoopUnswitch.cpp
index 678652d646..2c75f637f4 100644
--- a/lib/Transforms/Scalar/LoopUnswitch.cpp
+++ b/lib/Transforms/Scalar/LoopUnswitch.cpp
@@ -436,7 +436,7 @@ bool LoopUnswitch::processCurrentLoop() {
       Value *LoopCond = FindLIVLoopCondition(SI->getCondition(), 
                                              currentLoop, Changed);
       unsigned NumCases = SI->getNumCases(); 
-      if (LoopCond && NumCases > 1) {
+      if (LoopCond && NumCases) {
         // Find a value to unswitch on:
         // FIXME: this should chose the most expensive case!
         // FIXME: scan for a case with a non-critical edge?
@@ -445,7 +445,7 @@ bool LoopUnswitch::processCurrentLoop() {
         // Do not process same value again and again.
         // At this point we have some cases already unswitched and
         // some not yet unswitched. Let's find the first not yet unswitched one.
-        for (unsigned i = 1; i < NumCases; ++i) {
+        for (unsigned i = 0; i < NumCases; ++i) {
           Constant* UnswitchValCandidate = SI->getCaseValue(i);
           if (!BranchesInfo.isUnswitched(SI, UnswitchValCandidate)) {
             UnswitchVal = UnswitchValCandidate;
@@ -574,10 +574,10 @@ bool LoopUnswitch::IsTrivialUnswitchCondition(Value *Cond, Constant **Val,
     // this. 
     // Note that we can't trivially unswitch on the default case or
     // on already unswitched cases.
-    for (unsigned i = 1, e = SI->getNumSuccessors(); i != e; ++i) {
+    for (unsigned i = 0, e = SI->getNumCases(); i != e; ++i) {
       BasicBlock* LoopExitCandidate;
       if ((LoopExitCandidate = isTrivialLoopExitBlock(currentLoop, 
-                                               SI->getSuccessor(i)))) {
+                                               SI->getCaseSuccessor(i)))) {
         // Okay, we found a trivial case, remember the value that is trivial.
         ConstantInt* CaseVal = SI->getCaseValue(i);
 
@@ -1118,14 +1118,15 @@ void LoopUnswitch::RewriteLoopBodyWithConditionConstant(Loop *L, Value *LIC,
     if (SI == 0 || !isa<ConstantInt>(Val)) continue;
     
     unsigned DeadCase = SI->findCaseValue(cast<ConstantInt>(Val));
-    if (DeadCase == 0) continue;  // Default case is live for multiple values.
+    // Default case is live for multiple values.
+    if (DeadCase == SwitchInst::ErrorIndex) continue;
     
     // Found a dead case value.  Don't remove PHI nodes in the 
     // successor if they become single-entry, those PHI nodes may
     // be in the Users list.
 
     BasicBlock *Switch = SI->getParent();
-    BasicBlock *SISucc = SI->getSuccessor(DeadCase);
+    BasicBlock *SISucc = SI->getCaseSuccessor(DeadCase);
     BasicBlock *Latch = L->getLoopLatch();
     
     BranchesInfo.setUnswitched(SI, Val);
@@ -1145,7 +1146,7 @@ void LoopUnswitch::RewriteLoopBodyWithConditionConstant(Loop *L, Value *LIC,
     // Compute the successors instead of relying on the return value
     // of SplitEdge, since it may have split the switch successor
     // after PHI nodes.
-    BasicBlock *NewSISucc = SI->getSuccessor(DeadCase);
+    BasicBlock *NewSISucc = SI->getCaseSuccessor(DeadCase);
     BasicBlock *OldSISucc = *succ_begin(NewSISucc);
     // Create an "unreachable" destination.
     BasicBlock *Abort = BasicBlock::Create(Context, "us-unreachable",
diff --git a/lib/Transforms/Scalar/SCCP.cpp b/lib/Transforms/Scalar/SCCP.cpp
index 1f8f452c36..4274b509d2 100644
--- a/lib/Transforms/Scalar/SCCP.cpp
+++ b/lib/Transforms/Scalar/SCCP.cpp
@@ -550,7 +550,7 @@ void SCCPSolver::getFeasibleSuccessors(TerminatorInst &TI,
   }
 
   if (SwitchInst *SI = dyn_cast<SwitchInst>(&TI)) {
-    if (TI.getNumSuccessors() < 2) {
+    if (!SI->getNumCases()) {
       Succs[0] = true;
       return;
     }
@@ -564,7 +564,7 @@ void SCCPSolver::getFeasibleSuccessors(TerminatorInst &TI,
       return;
     }
 
-    Succs[SI->findCaseValue(CI)] = true;
+    Succs[SI->resolveSuccessorIndex(SI->findCaseValue(CI))] = true;
     return;
   }
 
@@ -614,7 +614,7 @@ bool SCCPSolver::isEdgeFeasible(BasicBlock *From, BasicBlock *To) {
     return true;
 
   if (SwitchInst *SI = dyn_cast<SwitchInst>(TI)) {
-    if (SI->getNumSuccessors() < 2)
+    if (SI->getNumCases() < 1)
       return true;
 
     LatticeVal SCValue = getValueState(SI->getCondition());
@@ -624,9 +624,9 @@ bool SCCPSolver::isEdgeFeasible(BasicBlock *From, BasicBlock *To) {
       return !SCValue.isUndefined();
 
     // Make sure to skip the "default value" which isn't a value
-    for (unsigned i = 1, E = SI->getNumSuccessors(); i != E; ++i)
-      if (SI->getSuccessorValue(i) == CI) // Found the taken branch.
-        return SI->getSuccessor(i) == To;
+    for (unsigned i = 0, E = SI->getNumCases(); i != E; ++i)
+      if (SI->getCaseValue(i) == CI) // Found the taken branch.
+        return SI->getCaseSuccessor(i) == To;
 
     // If the constant value is not equal to any of the branches, we must
     // execute default branch.
@@ -1487,7 +1487,7 @@ bool SCCPSolver::ResolvedUndefsIn(Function &F) {
     }
 
     if (SwitchInst *SI = dyn_cast<SwitchInst>(TI)) {
-      if (SI->getNumSuccessors() < 2)   // no cases
+      if (!SI->getNumCases())
         continue;
       if (!getValueState(SI->getCondition()).isUndefined())
         continue;
@@ -1495,12 +1495,12 @@ bool SCCPSolver::ResolvedUndefsIn(Function &F) {
       // If the input to SCCP is actually switch on undef, fix the undef to
       // the first constant.
       if (isa<UndefValue>(SI->getCondition())) {
-        SI->setCondition(SI->getCaseValue(1));
-        markEdgeExecutable(BB, TI->getSuccessor(1));
+        SI->setCondition(SI->getCaseValue(0));
+        markEdgeExecutable(BB, SI->getCaseSuccessor(0));
         return true;
       }
 
-      markForcedConstant(SI->getCondition(), SI->getCaseValue(1));
+      markForcedConstant(SI->getCondition(), SI->getCaseValue(0));
       return true;
     }
   }
diff --git a/lib/Transforms/Utils/CloneFunction.cpp b/lib/Transforms/Utils/CloneFunction.cpp
index 6ddbed2bbe..f817a21cbd 100644
--- a/lib/Transforms/Utils/CloneFunction.cpp
+++ b/lib/Transforms/Utils/CloneFunction.cpp
@@ -314,7 +314,8 @@ void PruningFunctionCloner::CloneBlock(const BasicBlock *BB,
       Cond = dyn_cast_or_null<ConstantInt>(V);
     }
     if (Cond) {     // Constant fold to uncond branch!
-      BasicBlock *Dest = SI->getSuccessor(SI->findCaseValue(Cond));
+      unsigned CaseIndex = SI->findCaseValue(Cond);
+      BasicBlock *Dest = SI->getSuccessor(SI->resolveSuccessorIndex(CaseIndex));
       VMap[OldTI] = BranchInst::Create(Dest, NewBB);
       ToClone.push_back(Dest);
       TerminatorDone = true;
diff --git a/lib/Transforms/Utils/CodeExtractor.cpp b/lib/Transforms/Utils/CodeExtractor.cpp
index 5f47ebb782..429919b79a 100644
--- a/lib/Transforms/Utils/CodeExtractor.cpp
+++ b/lib/Transforms/Utils/CodeExtractor.cpp
@@ -615,9 +615,9 @@ emitCallAndSwitchStatement(Function *newFunction, BasicBlock *codeReplacer,
   default:
     // Otherwise, make the default destination of the switch instruction be one
     // of the other successors.
-    TheSwitch->setOperand(0, call);
-    TheSwitch->setSuccessor(0, TheSwitch->getSuccessor(NumExitBlocks));
-    TheSwitch->removeCase(NumExitBlocks);  // Remove redundant case
+    TheSwitch->setCondition(call);
+    TheSwitch->setDefaultDest(TheSwitch->getSuccessor(NumExitBlocks));
+    TheSwitch->removeCase(NumExitBlocks-1);  // Remove redundant case
     break;
   }
 }
diff --git a/lib/Transforms/Utils/Local.cpp b/lib/Transforms/Utils/Local.cpp
index 4dd93cf2c7..336d8f63ec 100644
--- a/lib/Transforms/Utils/Local.cpp
+++ b/lib/Transforms/Utils/Local.cpp
@@ -106,22 +106,20 @@ bool llvm::ConstantFoldTerminator(BasicBlock *BB, bool DeleteDeadConditions) {
     // If we are switching on a constant, we can convert the switch into a
     // single branch instruction!
     ConstantInt *CI = dyn_cast<ConstantInt>(SI->getCondition());
-    BasicBlock *TheOnlyDest = SI->getSuccessor(0);  // The default dest
+    BasicBlock *TheOnlyDest = SI->getDefaultDest();  // The default dest
     BasicBlock *DefaultDest = TheOnlyDest;
-    assert(TheOnlyDest == SI->getDefaultDest() &&
-           "Default destination is not successor #0?");
 
     // Figure out which case it goes to.
-    for (unsigned i = 1, e = SI->getNumSuccessors(); i != e; ++i) {
+    for (unsigned i = 0, e = SI->getNumCases(); i != e; ++i) {
       // Found case matching a constant operand?
-      if (SI->getSuccessorValue(i) == CI) {
-        TheOnlyDest = SI->getSuccessor(i);
+      if (SI->getCaseValue(i) == CI) {
+        TheOnlyDest = SI->getCaseSuccessor(i);
         break;
       }
 
       // Check to see if this branch is going to the same place as the default
       // dest.  If so, eliminate it as an explicit compare.
-      if (SI->getSuccessor(i) == DefaultDest) {
+      if (SI->getCaseSuccessor(i) == DefaultDest) {
         // Remove this entry.
         DefaultDest->removePredecessor(SI->getParent());
         SI->removeCase(i);
@@ -132,7 +130,7 @@ bool llvm::ConstantFoldTerminator(BasicBlock *BB, bool DeleteDeadConditions) {
       // Otherwise, check to see if the switch only branches to one destination.
       // We do this by reseting "TheOnlyDest" to null when we find two non-equal
       // destinations.
-      if (SI->getSuccessor(i) != TheOnlyDest) TheOnlyDest = 0;
+      if (SI->getCaseSuccessor(i) != TheOnlyDest) TheOnlyDest = 0;
     }
 
     if (CI && !TheOnlyDest) {
@@ -166,14 +164,14 @@ bool llvm::ConstantFoldTerminator(BasicBlock *BB, bool DeleteDeadConditions) {
       return true;
     }
     
-    if (SI->getNumSuccessors() == 2) {
+    if (SI->getNumCases() == 1) {
       // Otherwise, we can fold this switch into a conditional branch
       // instruction if it has only one non-default destination.
       Value *Cond = Builder.CreateICmpEQ(SI->getCondition(),
-                                         SI->getSuccessorValue(1), "cond");
+                                         SI->getCaseValue(0), "cond");
 
       // Insert the new branch.
-      Builder.CreateCondBr(Cond, SI->getSuccessor(1), SI->getSuccessor(0));
+      Builder.CreateCondBr(Cond, SI->getCaseSuccessor(0), SI->getDefaultDest());
 
       // Delete the old switch.
       SI->eraseFromParent();
diff --git a/lib/Transforms/Utils/LowerExpectIntrinsic.cpp b/lib/Transforms/Utils/LowerExpectIntrinsic.cpp
index 9fdc06a713..df8d68ec8b 100644
--- a/lib/Transforms/Utils/LowerExpectIntrinsic.cpp
+++ b/lib/Transforms/Utils/LowerExpectIntrinsic.cpp
@@ -76,11 +76,14 @@ bool LowerExpectIntrinsic::HandleSwitchExpect(SwitchInst *SI) {
   unsigned caseNo = SI->findCaseValue(ExpectedValue);
   std::vector<Value *> Vec;
   unsigned n = SI->getNumCases();
-  Vec.resize(n + 1); // +1 for MDString
+  Vec.resize(n + 1 + 1); // +1 for MDString and +1 for default case
 
   Vec[0] = MDString::get(Context, "branch_weights");
+  Vec[1] = ConstantInt::get(Int32Ty, SwitchInst::ErrorIndex == caseNo ?
+                            LikelyBranchWeight : UnlikelyBranchWeight);
   for (unsigned i = 0; i < n; ++i) {
-    Vec[i + 1] = ConstantInt::get(Int32Ty, i == caseNo ? LikelyBranchWeight : UnlikelyBranchWeight);
+    Vec[i + 1 + 1] = ConstantInt::get(Int32Ty, i == caseNo ?
+        LikelyBranchWeight : UnlikelyBranchWeight);
   }
 
   MDNode *WeightsNode = llvm::MDNode::get(Context, Vec);
diff --git a/lib/Transforms/Utils/LowerSwitch.cpp b/lib/Transforms/Utils/LowerSwitch.cpp
index 686178ca01..424f564774 100644
--- a/lib/Transforms/Utils/LowerSwitch.cpp
+++ b/lib/Transforms/Utils/LowerSwitch.cpp
@@ -237,10 +237,10 @@ unsigned LowerSwitch::Clusterify(CaseVector& Cases, SwitchInst *SI) {
   unsigned numCmps = 0;
 
   // Start with "simple" cases
-  for (unsigned i = 1; i < SI->getNumSuccessors(); ++i)
-    Cases.push_back(CaseRange(SI->getSuccessorValue(i),
-                              SI->getSuccessorValue(i),
-                              SI->getSuccessor(i)));
+  for (unsigned i = 0; i < SI->getNumCases(); ++i)
+    Cases.push_back(CaseRange(SI->getCaseValue(i),
+                              SI->getCaseValue(i),
+                              SI->getCaseSuccessor(i)));
   std::sort(Cases.begin(), Cases.end(), CaseCmp());
 
   // Merge case into clusters
@@ -281,7 +281,7 @@ void LowerSwitch::processSwitchInst(SwitchInst *SI) {
   BasicBlock* Default = SI->getDefaultDest();
 
   // If there is only the default destination, don't bother with the code below.
-  if (SI->getNumCases() == 1) {
+  if (!SI->getNumCases()) {
     BranchInst::Create(SI->getDefaultDest(), CurBlock);
     CurBlock->getInstList().erase(SI);
     return;
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp
index d5ae609679..a938b99649 100644
--- a/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -481,8 +481,9 @@ GetValueEqualityComparisonCases(TerminatorInst *TI,
                                                       BasicBlock*> > &Cases) {
   if (SwitchInst *SI = dyn_cast<SwitchInst>(TI)) {
     Cases.reserve(SI->getNumCases());
-    for (unsigned i = 1, e = SI->getNumCases(); i != e; ++i)
-      Cases.push_back(std::make_pair(SI->getCaseValue(i), SI->getSuccessor(i)));
+    for (unsigned i = 0, e = SI->getNumCases(); i != e; ++i)
+      Cases.push_back(std::make_pair(SI->getCaseValue(i),
+                                     SI->getCaseSuccessor(i)));
     return SI->getDefaultDest();
   }
 
@@ -605,11 +606,13 @@ SimplifyEqualityComparisonWithOnlyPredecessor(TerminatorInst *TI,
     DEBUG(dbgs() << "Threading pred instr: " << *Pred->getTerminator()
                  << "Through successor TI: " << *TI);
 
-    for (unsigned i = SI->getNumCases()-1; i != 0; --i)
+    for (unsigned i = SI->getNumCases(); i != 0;) {
+      --i;
       if (DeadCases.count(SI->getCaseValue(i))) {
-        SI->getSuccessor(i)->removePredecessor(TI->getParent());
+        SI->getCaseSuccessor(i)->removePredecessor(TI->getParent());
         SI->removeCase(i);
       }
+    }
 
     DEBUG(dbgs() << "Leaving: " << *TI << "\n");
     return true;
@@ -2007,8 +2010,10 @@ static bool SimplifySwitchOnSelect(SwitchInst *SI, SelectInst *Select) {
 
   // Find the relevant condition and destinations.
   Value *Condition = Select->getCondition();
-  BasicBlock *TrueBB = SI->getSuccessor(SI->findCaseValue(TrueVal));
-  BasicBlock *FalseBB = SI->getSuccessor(SI->findCaseValue(FalseVal));
+  unsigned TrueCase = SI->findCaseValue(TrueVal);
+  unsigned FalseCase = SI->findCaseValue(FalseVal);
+  BasicBlock *TrueBB = SI->getSuccessor(SI->resolveSuccessorIndex(TrueCase));
+  BasicBlock *FalseBB = SI->getSuccessor(SI->resolveSuccessorIndex(FalseCase));
 
   // Perform the actual simplification.
   return SimplifyTerminatorOnSelect(SI, Condition, TrueBB, FalseBB);
@@ -2092,7 +2097,7 @@ static bool TryToSimplifyUncondBranchWithICmpInIt(ICmpInst *ICI,
   // Ok, the block is reachable from the default dest.  If the constant we're
   // comparing exists in one of the other edges, then we can constant fold ICI
   // and zap it.
-  if (SI->findCaseValue(Cst) != 0) {
+  if (SI->findCaseValue(Cst) != SwitchInst::ErrorIndex) {
     Value *V;
     if (ICI->getPredicate() == ICmpInst::ICMP_EQ)
       V = ConstantInt::getFalse(BB->getContext());
@@ -2465,8 +2470,8 @@ bool SimplifyCFGOpt::SimplifyUnreachable(UnreachableInst *UI) {
         }
       }
     } else if (SwitchInst *SI = dyn_cast<SwitchInst>(TI)) {
-      for (unsigned i = 1, e = SI->getNumCases(); i != e; ++i)
-        if (SI->getSuccessor(i) == BB) {
+      for (unsigned i = 0, e = SI->getNumCases(); i != e; ++i)
+        if (SI->getCaseSuccessor(i) == BB) {
           BB->removePredecessor(SI->getParent());
           SI->removeCase(i);
           --i; --e;
@@ -2474,11 +2479,11 @@ bool SimplifyCFGOpt::SimplifyUnreachable(UnreachableInst *UI) {
         }
       // If the default value is unreachable, figure out the most popular
       // destination and make it the default.
-      if (SI->getSuccessor(0) == BB) {
+      if (SI->getDefaultDest() == BB) {
         std::map<BasicBlock*, std::pair<unsigned, unsigned> > Popularity;
-        for (unsigned i = 1, e = SI->getNumCases(); i != e; ++i) {
+        for (unsigned i = 0, e = SI->getNumCases(); i != e; ++i) {
           std::pair<unsigned, unsigned> &entry =
-              Popularity[SI->getSuccessor(i)];
+              Popularity[SI->getCaseSuccessor(i)];
           if (entry.first == 0) {
             entry.first = 1;
             entry.second = i;
@@ -2503,7 +2508,7 @@ bool SimplifyCFGOpt::SimplifyUnreachable(UnreachableInst *UI) {
         if (MaxBlock) {
           // Make this the new default, allowing us to delete any explicit
           // edges to it.
-          SI->setSuccessor(0, MaxBlock);
+          SI->setDefaultDest(MaxBlock);
           Changed = true;
           
           // If MaxBlock has phinodes in it, remove MaxPop-1 entries from
@@ -2512,8 +2517,8 @@ bool SimplifyCFGOpt::SimplifyUnreachable(UnreachableInst *UI) {
             for (unsigned i = 0; i != MaxPop-1; ++i)
               MaxBlock->removePredecessor(SI->getParent());
           
-          for (unsigned i = 1, e = SI->getNumCases(); i != e; ++i)
-            if (SI->getSuccessor(i) == MaxBlock) {
+          for (unsigned i = 0, e = SI->getNumCases(); i != e; ++i)
+            if (SI->getCaseSuccessor(i) == MaxBlock) {
               SI->removeCase(i);
               --i; --e;
             }
@@ -2555,17 +2560,17 @@ bool SimplifyCFGOpt::SimplifyUnreachable(UnreachableInst *UI) {
 /// TurnSwitchRangeIntoICmp - Turns a switch with that contains only a
 /// integer range comparison into a sub, an icmp and a branch.
 static bool TurnSwitchRangeIntoICmp(SwitchInst *SI, IRBuilder<> &Builder) {
-  assert(SI->getNumCases() > 2 && "Degenerate switch?");
+  assert(SI->getNumCases() > 1 && "Degenerate switch?");
 
   // Make sure all cases point to the same destination and gather the values.
   SmallVector<ConstantInt *, 16> Cases;
-  Cases.push_back(SI->getCaseValue(1));
-  for (unsigned I = 2, E = SI->getNumCases(); I != E; ++I) {
-    if (SI->getSuccessor(I-1) != SI->getSuccessor(I))
+  Cases.push_back(SI->getCaseValue(0));
+  for (unsigned I = 1, E = SI->getNumCases(); I != E; ++I) {
+    if (SI->getCaseSuccessor(I-1) != SI->getCaseSuccessor(I))
       return false;
     Cases.push_back(SI->getCaseValue(I));
   }
-  assert(Cases.size() == SI->getNumCases()-1 && "Not all cases gathered");
+  assert(Cases.size() == SI->getNumCases() && "Not all cases gathered");
 
   // Sort the case values, then check if they form a range we can transform.
   array_pod_sort(Cases.begin(), Cases.end(), ConstantIntSortPredicate);
@@ -2575,18 +2580,18 @@ static bool TurnSwitchRangeIntoICmp(SwitchInst *SI, IRBuilder<> &Builder) {
   }
 
   Constant *Offset = ConstantExpr::getNeg(Cases.back());
-  Constant *NumCases = ConstantInt::get(Offset->getType(), SI->getNumCases()-1);
+  Constant *NumCases = ConstantInt::get(Offset->getType(), SI->getNumCases());
 
   Value *Sub = SI->getCondition();
   if (!Offset->isNullValue())
     Sub = Builder.CreateAdd(Sub, Offset, Sub->getName()+".off");
   Value *Cmp = Builder.CreateICmpULT(Sub, NumCases, "switch");
-  Builder.CreateCondBr(Cmp, SI->getSuccessor(1), SI->getDefaultDest());
+  Builder.CreateCondBr(Cmp, SI->getCaseSuccessor(0), SI->getDefaultDest());
 
   // Prune obsolete incoming values off the successor's PHI nodes.
-  for (BasicBlock::iterator BBI = SI->getSuccessor(1)->begin();
+  for (BasicBlock::iterator BBI = SI->getCaseSuccessor(0)->begin();
        isa<PHINode>(BBI); ++BBI) {
-    for (unsigned I = 0, E = SI->getNumCases()-2; I != E; ++I)
+    for (unsigned I = 0, E = SI->getNumCases()-1; I != E; ++I)
       cast<PHINode>(BBI)->removeIncomingValue(SI->getParent());
   }
   SI->eraseFromParent();
@@ -2604,7 +2609,7 @@ static bool EliminateDeadSwitchCases(SwitchInst *SI) {
 
   // Gather dead cases.
   SmallVector<ConstantInt*, 8> DeadCases;
-  for (unsigned I = 1, E = SI->getNumCases(); I != E; ++I) {
+  for (unsigned I = 0, E = SI->getNumCases(); I != E; ++I) {
     if ((SI->getCaseValue(I)->getValue() & KnownZero) != 0 ||
         (SI->getCaseValue(I)->getValue() & KnownOne) != KnownOne) {
       DeadCases.push_back(SI->getCaseValue(I));
@@ -2616,8 +2621,10 @@ static bool EliminateDeadSwitchCases(SwitchInst *SI) {
   // Remove dead cases from the switch.
   for (unsigned I = 0, E = DeadCases.size(); I != E; ++I) {
     unsigned Case = SI->findCaseValue(DeadCases[I]);
+    assert(Case != SwitchInst::ErrorIndex &&
+           "Case was not found. Probably mistake in DeadCases forming.");
     // Prune unused values from PHI nodes.
-    SI->getSuccessor(Case)->removePredecessor(SI->getParent());
+    SI->getCaseSuccessor(Case)->removePredecessor(SI->getParent());
     SI->removeCase(Case);
   }
 
@@ -2666,9 +2673,9 @@ static bool ForwardSwitchConditionToPHI(SwitchInst *SI) {
   typedef DenseMap<PHINode*, SmallVector<int,4> > ForwardingNodesMap;
   ForwardingNodesMap ForwardingNodes;
 
-  for (unsigned I = 1; I < SI->getNumCases(); ++I) { // 0 is the default case.
+  for (unsigned I = 0; I < SI->getNumCases(); ++I) { // 0 is the default case.
     ConstantInt *CaseValue = SI->getCaseValue(I);
-    BasicBlock *CaseDest = SI->getSuccessor(I);
+    BasicBlock *CaseDest = SI->getCaseSuccessor(I);
 
     int PhiIndex;
     PHINode *PHI = FindPHIForConditionForwarding(CaseValue, CaseDest,
diff --git a/lib/VMCore/AsmWriter.cpp b/lib/VMCore/AsmWriter.cpp
index eb0f66196d..e6576c5bf7 100644
--- a/lib/VMCore/AsmWriter.cpp
+++ b/lib/VMCore/AsmWriter.cpp
@@ -1738,13 +1738,12 @@ void AssemblyWriter::printInstruction(const Instruction &I) {
     Out << ", ";
     writeOperand(SI.getDefaultDest(), true);
     Out << " [";
-    // Skip the first item since that's the default case.
     unsigned NumCases = SI.getNumCases();
-    for (unsigned i = 1; i < NumCases; ++i) {
+    for (unsigned i = 0; i < NumCases; ++i) {
       Out << "\n    ";
       writeOperand(SI.getCaseValue(i), true);
       Out << ", ";
-      writeOperand(SI.getSuccessor(i), true);
+      writeOperand(SI.getCaseSuccessor(i), true);
     }
     Out << "\n  ]";
   } else if (isa<IndirectBrInst>(I)) {
diff --git a/lib/VMCore/Instructions.cpp b/lib/VMCore/Instructions.cpp
index 301791dd0b..c0e6844271 100644
--- a/lib/VMCore/Instructions.cpp
+++ b/lib/VMCore/Instructions.cpp
@@ -3195,31 +3195,29 @@ SwitchInst::~SwitchInst() {
 /// addCase - Add an entry to the switch instruction...
 ///
 void SwitchInst::addCase(ConstantInt *OnVal, BasicBlock *Dest) {
+  unsigned NewCaseIdx = getNumCases(); 
   unsigned OpNo = NumOperands;
   if (OpNo+2 > ReservedSpace)
     growOperands();  // Get more space!
   // Initialize some new operands.
   assert(OpNo+1 < ReservedSpace && "Growing didn't work!");
   NumOperands = OpNo+2;
-  OperandList[OpNo] = OnVal;
-  OperandList[OpNo+1] = Dest;
+  setCaseValue(NewCaseIdx, OnVal);
+  setCaseSuccessor(NewCaseIdx, Dest);
 }
 
-/// removeCase - This method removes the specified successor from the switch
-/// instruction.  Note that this cannot be used to remove the default
-/// destination (successor #0).
-///
+/// removeCase - This method removes the specified case and its successor
+/// from the switch instruction.
 void SwitchInst::removeCase(unsigned idx) {
-  assert(idx != 0 && "Cannot remove the default case!");
-  assert(idx*2 < getNumOperands() && "Successor index out of range!!!");
+  assert(2 + idx*2 < getNumOperands() && "Case index out of range!!!");
 
   unsigned NumOps = getNumOperands();
   Use *OL = OperandList;
 
   // Overwrite this case with the end of the list.
-  if ((idx + 1) * 2 != NumOps) {
-    OL[idx * 2] = OL[NumOps - 2];
-    OL[idx * 2 + 1] = OL[NumOps - 1];
+  if (2 + (idx + 1) * 2 != NumOps) {
+    OL[2 + idx * 2] = OL[NumOps - 2];
+    OL[2 + idx * 2 + 1] = OL[NumOps - 1];
   }
 
   // Nuke the last value.
diff --git a/lib/VMCore/Verifier.cpp b/lib/VMCore/Verifier.cpp
index b678f251b3..642930352f 100644
--- a/lib/VMCore/Verifier.cpp
+++ b/lib/VMCore/Verifier.cpp
@@ -812,7 +812,7 @@ void Verifier::visitSwitchInst(SwitchInst &SI) {
   // have the same type as the switched-on value.
   Type *SwitchTy = SI.getCondition()->getType();
   SmallPtrSet<ConstantInt*, 32> Constants;
-  for (unsigned i = 1, e = SI.getNumCases(); i != e; ++i) {
+  for (unsigned i = 0, e = SI.getNumCases(); i != e; ++i) {
     Assert1(SI.getCaseValue(i)->getType() == SwitchTy,
             "Switch constants must all be same type as switch value!", &SI);
     Assert2(Constants.insert(SI.getCaseValue(i)),
diff --git a/tools/llvm-diff/DifferenceEngine.cpp b/tools/llvm-diff/DifferenceEngine.cpp
index e827b23a73..8113fd4c66 100644
--- a/tools/llvm-diff/DifferenceEngine.cpp
+++ b/tools/llvm-diff/DifferenceEngine.cpp
@@ -319,13 +319,13 @@ class FunctionDifferenceEngine {
       bool Difference = false;
 
       DenseMap<ConstantInt*,BasicBlock*> LCases;
-      for (unsigned I = 1, E = LI->getNumCases(); I != E; ++I)
-        LCases[LI->getCaseValue(I)] = LI->getSuccessor(I);
-      for (unsigned I = 1, E = RI->getNumCases(); I != E; ++I) {
+      for (unsigned I = 0, E = LI->getNumCases(); I != E; ++I)
+        LCases[LI->getCaseValue(I)] = LI->getCaseSuccessor(I);
+      for (unsigned I = 0, E = RI->getNumCases(); I != E; ++I) {
         ConstantInt *CaseValue = RI->getCaseValue(I);
         BasicBlock *LCase = LCases[CaseValue];
         if (LCase) {
-          if (TryUnify) tryUnify(LCase, RI->getSuccessor(I));
+          if (TryUnify) tryUnify(LCase, RI->getCaseSuccessor(I));
           LCases.erase(CaseValue);
         } else if (Complain || !Difference) {
           if (Complain)