Move isLCSSAForm, isLoopInvariant, getCanonicalInductionVariable,

and related functions out of LoopBase and into Loop, since they
are specific to BasicBlock-based loops. This also allows the code
to be moved out-of-line.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75523 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 51 insertions, 222 deletions

diff --git a/include/llvm/Analysis/LoopInfo.h b/include/llvm/Analysis/LoopInfo.h
index 10b78077ea..2bed04b3b2 100644
--- a/include/llvm/Analysis/LoopInfo.h
+++ b/include/llvm/Analysis/LoopInfo.h
@@ -31,11 +31,8 @@
 #define LLVM_ANALYSIS_LOOP_INFO_H
 
 #include "llvm/Pass.h"
-#include "llvm/Constants.h"
-#include "llvm/Instructions.h"
 #include "llvm/ADT/DepthFirstIterator.h"
 #include "llvm/ADT/GraphTraits.h"
-#include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Analysis/Dominators.h"
 #include "llvm/Support/CFG.h"
@@ -147,14 +144,6 @@ public:
     return NumBackEdges;
   }
 
-  /// isLoopInvariant - Return true if the specified value is loop invariant
-  ///
-  inline bool isLoopInvariant(Value *V) const {
-    if (Instruction *I = dyn_cast<Instruction>(V))
-      return !contains(I->getParent());
-    return true;  // All non-instructions are loop invariant
-  }
-
   //===--------------------------------------------------------------------===//
   // APIs for simple analysis of the loop.
   //
@@ -356,178 +345,6 @@ public:
 
     return Latch;
   }
-  
-  /// getCanonicalInductionVariable - Check to see if the loop has a canonical
-  /// induction variable: an integer recurrence that starts at 0 and increments
-  /// by one each time through the loop.  If so, return the phi node that
-  /// corresponds to it.
-  ///
-  /// The IndVarSimplify pass transforms loops to have a canonical induction
-  /// variable.
-  ///
-  inline PHINode *getCanonicalInductionVariable() const {
-    BlockT *H = getHeader();
-
-    BlockT *Incoming = 0, *Backedge = 0;
-    typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
-    typename InvBlockTraits::ChildIteratorType PI =
-                                                 InvBlockTraits::child_begin(H);
-    assert(PI != InvBlockTraits::child_end(H) &&
-           "Loop must have at least one backedge!");
-    Backedge = *PI++;
-    if (PI == InvBlockTraits::child_end(H)) return 0;  // dead loop
-    Incoming = *PI++;
-    if (PI != InvBlockTraits::child_end(H)) return 0;  // multiple backedges?
-
-    if (contains(Incoming)) {
-      if (contains(Backedge))
-        return 0;
-      std::swap(Incoming, Backedge);
-    } else if (!contains(Backedge))
-      return 0;
-
-    // Loop over all of the PHI nodes, looking for a canonical indvar.
-    for (typename BlockT::iterator I = H->begin(); isa<PHINode>(I); ++I) {
-      PHINode *PN = cast<PHINode>(I);
-      if (ConstantInt *CI =
-          dyn_cast<ConstantInt>(PN->getIncomingValueForBlock(Incoming)))
-        if (CI->isNullValue())
-          if (Instruction *Inc =
-              dyn_cast<Instruction>(PN->getIncomingValueForBlock(Backedge)))
-            if (Inc->getOpcode() == Instruction::Add &&
-                Inc->getOperand(0) == PN)
-              if (ConstantInt *CI = dyn_cast<ConstantInt>(Inc->getOperand(1)))
-                if (CI->equalsInt(1))
-                  return PN;
-    }
-    return 0;
-  }
-
-  /// getCanonicalInductionVariableIncrement - Return the LLVM value that holds
-  /// the canonical induction variable value for the "next" iteration of the
-  /// loop.  This always succeeds if getCanonicalInductionVariable succeeds.
-  ///
-  inline Instruction *getCanonicalInductionVariableIncrement() const {
-    if (PHINode *PN = getCanonicalInductionVariable()) {
-      bool P1InLoop = contains(PN->getIncomingBlock(1));
-      return cast<Instruction>(PN->getIncomingValue(P1InLoop));
-    }
-    return 0;
-  }
-
-  /// getTripCount - Return a loop-invariant LLVM value indicating the number of
-  /// times the loop will be executed.  Note that this means that the backedge
-  /// of the loop executes N-1 times.  If the trip-count cannot be determined,
-  /// this returns null.
-  ///
-  /// The IndVarSimplify pass transforms loops to have a form that this
-  /// function easily understands.
-  ///
-  inline Value *getTripCount() const {
-    // Canonical loops will end with a 'cmp ne I, V', where I is the incremented
-    // canonical induction variable and V is the trip count of the loop.
-    Instruction *Inc = getCanonicalInductionVariableIncrement();
-    if (Inc == 0) return 0;
-    PHINode *IV = cast<PHINode>(Inc->getOperand(0));
-
-    BlockT *BackedgeBlock =
-            IV->getIncomingBlock(contains(IV->getIncomingBlock(1)));
-
-    if (BranchInst *BI = dyn_cast<BranchInst>(BackedgeBlock->getTerminator()))
-      if (BI->isConditional()) {
-        if (ICmpInst *ICI = dyn_cast<ICmpInst>(BI->getCondition())) {
-          if (ICI->getOperand(0) == Inc) {
-            if (BI->getSuccessor(0) == getHeader()) {
-              if (ICI->getPredicate() == ICmpInst::ICMP_NE)
-                return ICI->getOperand(1);
-            } else if (ICI->getPredicate() == ICmpInst::ICMP_EQ) {
-              return ICI->getOperand(1);
-            }
-          }
-        }
-      }
-
-    return 0;
-  }
-  
-  /// getSmallConstantTripCount - Returns the trip count of this loop as a
-  /// normal unsigned value, if possible. Returns 0 if the trip count is unknown
-  /// of not constant. Will also return 0 if the trip count is very large 
-  /// (>= 2^32)
-  inline unsigned getSmallConstantTripCount() const {
-    Value* TripCount = this->getTripCount();
-    if (TripCount) {
-      if (ConstantInt *TripCountC = dyn_cast<ConstantInt>(TripCount)) {
-        // Guard against huge trip counts.
-        if (TripCountC->getValue().getActiveBits() <= 32) {
-          return (unsigned)TripCountC->getZExtValue();
-        }
-      }
-    }
-    return 0;
-  }
-
-  /// getSmallConstantTripMultiple - Returns the largest constant divisor of the
-  /// trip count of this loop as a normal unsigned value, if possible. This
-  /// means that the actual trip count is always a multiple of the returned
-  /// value (don't forget the trip count could very well be zero as well!).
-  ///
-  /// Returns 1 if the trip count is unknown or not guaranteed to be the
-  /// multiple of a constant (which is also the case if the trip count is simply
-  /// constant, use getSmallConstantTripCount for that case), Will also return 1
-  /// if the trip count is very large (>= 2^32).
-  inline unsigned getSmallConstantTripMultiple() const {
-    Value* TripCount = this->getTripCount();
-    // This will hold the ConstantInt result, if any
-    ConstantInt *Result = NULL;
-    if (TripCount) {
-      // See if the trip count is constant itself
-      Result = dyn_cast<ConstantInt>(TripCount);
-      // if not, see if it is a multiplication
-      if (!Result)
-        if (BinaryOperator *BO = dyn_cast<BinaryOperator>(TripCount)) {
-          switch (BO->getOpcode()) {
-          case BinaryOperator::Mul:
-            Result = dyn_cast<ConstantInt>(BO->getOperand(1));
-            break;
-          default: 
-            break;
-          }
-        }
-    }
-    // Guard against huge trip counts.
-    if (Result && Result->getValue().getActiveBits() <= 32) {
-      return (unsigned)Result->getZExtValue();
-    } else {
-      return 1;
-    }
-  }
-  
-  /// isLCSSAForm - Return true if the Loop is in LCSSA form
-  inline bool isLCSSAForm() const {
-    // Sort the blocks vector so that we can use binary search to do quick
-    // lookups.
-    SmallPtrSet<BlockT*, 16> LoopBBs(block_begin(), block_end());
-
-    for (block_iterator BI = block_begin(), E = block_end(); BI != E; ++BI) {
-      BlockT *BB = *BI;
-      for (typename BlockT::iterator I = BB->begin(), E = BB->end(); I != E;++I)
-        for (Value::use_iterator UI = I->use_begin(), E = I->use_end(); UI != E;
-             ++UI) {
-          BlockT *UserBB = cast<Instruction>(*UI)->getParent();
-          if (PHINode *P = dyn_cast<PHINode>(*UI)) {
-            UserBB = P->getIncomingBlock(UI);
-          }
-
-          // Check the current block, as a fast-path.  Most values are used in
-          // the same block they are defined in.
-          if (UserBB != BB && !LoopBBs.count(UserBB))
-            return false;
-        }
-    }
-
-    return true;
-  }
 
   //===--------------------------------------------------------------------===//
   // APIs for updating loop information after changing the CFG
@@ -654,6 +471,57 @@ protected:
 class Loop : public LoopBase<BasicBlock, Loop> {
 public:
   Loop() {}
+
+  /// isLoopInvariant - Return true if the specified value is loop invariant
+  ///
+  bool isLoopInvariant(Value *V) const;
+
+  /// getCanonicalInductionVariable - Check to see if the loop has a canonical
+  /// induction variable: an integer recurrence that starts at 0 and increments
+  /// by one each time through the loop.  If so, return the phi node that
+  /// corresponds to it.
+  ///
+  /// The IndVarSimplify pass transforms loops to have a canonical induction
+  /// variable.
+  ///
+  PHINode *getCanonicalInductionVariable() const;
+
+  /// getCanonicalInductionVariableIncrement - Return the LLVM value that holds
+  /// the canonical induction variable value for the "next" iteration of the
+  /// loop.  This always succeeds if getCanonicalInductionVariable succeeds.
+  ///
+  Instruction *getCanonicalInductionVariableIncrement() const;
+
+  /// getTripCount - Return a loop-invariant LLVM value indicating the number of
+  /// times the loop will be executed.  Note that this means that the backedge
+  /// of the loop executes N-1 times.  If the trip-count cannot be determined,
+  /// this returns null.
+  ///
+  /// The IndVarSimplify pass transforms loops to have a form that this
+  /// function easily understands.
+  ///
+  Value *getTripCount() const;
+
+  /// getSmallConstantTripCount - Returns the trip count of this loop as a
+  /// normal unsigned value, if possible. Returns 0 if the trip count is unknown
+  /// of not constant. Will also return 0 if the trip count is very large
+  /// (>= 2^32)
+  unsigned getSmallConstantTripCount() const;
+
+  /// getSmallConstantTripMultiple - Returns the largest constant divisor of the
+  /// trip count of this loop as a normal unsigned value, if possible. This
+  /// means that the actual trip count is always a multiple of the returned
+  /// value (don't forget the trip count could very well be zero as well!).
+  ///
+  /// Returns 1 if the trip count is unknown or not guaranteed to be the
+  /// multiple of a constant (which is also the case if the trip count is simply
+  /// constant, use getSmallConstantTripCount for that case), Will also return 1
+  /// if the trip count is very large (>= 2^32).
+  unsigned getSmallConstantTripMultiple() const;
+
+  /// isLCSSAForm - Return true if the Loop is in LCSSA form
+  bool isLCSSAForm() const;
+
 private:
   friend class LoopInfoBase<BasicBlock, Loop>;
   explicit Loop(BasicBlock *BB) : LoopBase<BasicBlock, Loop>(BB) {}
diff --git a/include/llvm/CodeGen/MachineLoopInfo.h b/include/llvm/CodeGen/MachineLoopInfo.h
index 1511b40897..65ad4e4841 100644
--- a/include/llvm/CodeGen/MachineLoopInfo.h
+++ b/include/llvm/CodeGen/MachineLoopInfo.h
@@ -35,45 +35,6 @@
 
 namespace llvm {
 
-class MachineLoop;
-
-// Provide overrides for Loop methods that don't make sense for machine loops.
-template<> inline
-PHINode *
-LoopBase<MachineBasicBlock, MachineLoop>::getCanonicalInductionVariable() const {
-  assert(0 && "getCanonicalInductionVariable not supported for machine loops!");
-  return 0;
-}
-
-template<> inline Instruction*
-LoopBase<MachineBasicBlock,
-         MachineLoop>::getCanonicalInductionVariableIncrement() const {
-  assert(0 &&
-     "getCanonicalInductionVariableIncrement not supported for machine loops!");
-  return 0;
-}
-
-template<>
-inline bool
-LoopBase<MachineBasicBlock, MachineLoop>::isLoopInvariant(Value *V) const {
-  assert(0 && "isLoopInvariant not supported for machine loops!");
-  return false;
-}
-
-template<>
-inline Value *
-LoopBase<MachineBasicBlock, MachineLoop>::getTripCount() const {
-  assert(0 && "getTripCount not supported for machine loops!");
-  return 0;
-}
-
-template<>
-inline bool
-LoopBase<MachineBasicBlock, MachineLoop>::isLCSSAForm() const {
-  assert(0 && "isLCSSAForm not supported for machine loops");
-  return false;
-}
-
 class MachineLoop : public LoopBase<MachineBasicBlock, MachineLoop> {
 public:
   MachineLoop();