LoopVectorize: Change API call to get the backedge taken count

Use ScalarEvolution's getBackedgeTakenCount API instead of getExitCount since
that is really what we want to know. Using the more specific getExitCount was
safe because we made sure that there is only one exiting block.

No functionality change.

llvm-svn: 183047

1 files changed, 3 insertions, 3 deletions

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 4482d13e596..3693f4a294e 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -1013,7 +1013,7 @@ LoopVectorizationLegality::RuntimePointerCheck::insert(ScalarEvolution *SE,
   const SCEV *Sc = SE->getSCEV(Ptr);
   const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Sc);
   assert(AR && "Invalid addrec expression");
-  const SCEV *Ex = SE->getExitCount(Lp, Lp->getLoopLatch());
+  const SCEV *Ex = SE->getBackedgeTakenCount(Lp);
   const SCEV *ScEnd = AR->evaluateAtIteration(Ex, *SE);
   Pointers.push_back(Ptr);
   Starts.push_back(AR->getStart());
@@ -1456,7 +1456,7 @@ InnerLoopVectorizer::createEmptyLoop(LoopVectorizationLegality *Legal) {
   Type *IdxTy = Legal->getWidestInductionType();
 
   // Find the loop boundaries.
-  const SCEV *ExitCount = SE->getExitCount(OrigLoop, OrigLoop->getLoopLatch());
+  const SCEV *ExitCount = SE->getBackedgeTakenCount(OrigLoop);
   assert(ExitCount != SE->getCouldNotCompute() && "Invalid loop count");
 
   // Get the total trip count from the count by adding 1.
@@ -2584,7 +2584,7 @@ bool LoopVectorizationLegality::canVectorize() {
         TheLoop->getHeader()->getName() << "\n");
 
   // ScalarEvolution needs to be able to find the exit count.
-  const SCEV *ExitCount = SE->getExitCount(TheLoop, Latch);
+  const SCEV *ExitCount = SE->getBackedgeTakenCount(TheLoop);
   if (ExitCount == SE->getCouldNotCompute()) {
     DEBUG(dbgs() << "LV: SCEV could not compute the loop exit count.\n");
     return false;