From: Dan Gohman <gohman@apple.com>
Date: Fri, 23 Jul 2010 21:34:51 +0000 (+0000)
Subject: Eliminate getCanonicalInductionVariableIncrement's last user and
X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=commitdiff_plain;h=f8336a75c2cffe3a0b9aae5b67faf742754d7eb3

Eliminate getCanonicalInductionVariableIncrement's last user and
eliminate it.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@109270 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/llvm/Analysis/LoopInfo.h b/include/llvm/Analysis/LoopInfo.h
index 5dfdc25dd88..2e90a9631fb 100644
--- a/include/llvm/Analysis/LoopInfo.h
+++ b/include/llvm/Analysis/LoopInfo.h
@@ -562,12 +562,6 @@ public:
   ///
   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,
diff --git a/lib/Analysis/LoopInfo.cpp b/lib/Analysis/LoopInfo.cpp
index b4333147a0c..46219d1b6f5 100644
--- a/lib/Analysis/LoopInfo.cpp
+++ b/lib/Analysis/LoopInfo.cpp
@@ -155,18 +155,6 @@ PHINode *Loop::getCanonicalInductionVariable() const {
   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.
-///
-Instruction *Loop::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,
@@ -178,12 +166,12 @@ Instruction *Loop::getCanonicalInductionVariableIncrement() const {
 Value *Loop::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));
+  PHINode *IV = getCanonicalInductionVariable();
+  if (IV == 0 || IV->getNumIncomingValues() != 2) return 0;
 
-  BasicBlock *BackedgeBlock =
-    IV->getIncomingBlock(contains(IV->getIncomingBlock(1)));
+  bool P0InLoop = contains(IV->getIncomingBlock(0));
+  Value *Inc = IV->getIncomingValue(!P0InLoop);
+  BasicBlock *BackedgeBlock = IV->getIncomingBlock(!P0InLoop);
 
   if (BranchInst *BI = dyn_cast<BranchInst>(BackedgeBlock->getTerminator()))
     if (BI->isConditional()) {