vendor/llvm/llvm-trunk-r307894

1 files changed, 7 insertions, 2 deletions

diff --git a/lib/Transforms/Vectorize/LoopVectorize.cpp b/lib/Transforms/Vectorize/LoopVectorize.cpp
index 193cc4d13787..eb82ee283d44 100644
--- a/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -5315,8 +5315,13 @@ void LoopVectorizationLegality::addInductionPhi(
 
   // Both the PHI node itself, and the "post-increment" value feeding
   // back into the PHI node may have external users.
-  AllowedExit.insert(Phi);
-  AllowedExit.insert(Phi->getIncomingValueForBlock(TheLoop->getLoopLatch()));
+  // We can allow those uses, except if the SCEVs we have for them rely
+  // on predicates that only hold within the loop, since allowing the exit
+  // currently means re-using this SCEV outside the loop.
+  if (PSE.getUnionPredicate().isAlwaysTrue()) {
+    AllowedExit.insert(Phi);
+    AllowedExit.insert(Phi->getIncomingValueForBlock(TheLoop->getLoopLatch()));
+  }
 
   DEBUG(dbgs() << "LV: Found an induction variable.\n");
   return;