vendor/llvm-project/llvmorg-10-init-17466-ge26a78e7085

1 files changed, 13 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorizationLegality.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorizationLegality.cpp
index f43842be5357..3f943f4c0688 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorizationLegality.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorizationLegality.cpp
@@ -72,7 +72,7 @@ LoopVectorizeHints::LoopVectorizeHints(const Loop *L,
       Interleave("interleave.count", InterleaveOnlyWhenForced, HK_UNROLL),
       Force("vectorize.enable", FK_Undefined, HK_FORCE),
       IsVectorized("isvectorized", 0, HK_ISVECTORIZED),
-      Predicate("vectorize.predicate.enable", 0, HK_PREDICATE), TheLoop(L),
+      Predicate("vectorize.predicate.enable", FK_Undefined, HK_PREDICATE), TheLoop(L),
       ORE(ORE) {
   // Populate values with existing loop metadata.
   getHintsFromMetadata();
@@ -815,6 +815,18 @@ bool LoopVectorizationLegality::canVectorizeInstrs() {
     }
   }
 
+  // For first order recurrences, we use the previous value (incoming value from
+  // the latch) to check if it dominates all users of the recurrence. Bail out
+  // if we have to sink such an instruction for another recurrence, as the
+  // dominance requirement may not hold after sinking.
+  BasicBlock *LoopLatch = TheLoop->getLoopLatch();
+  if (any_of(FirstOrderRecurrences, [LoopLatch, this](const PHINode *Phi) {
+        Instruction *V =
+            cast<Instruction>(Phi->getIncomingValueForBlock(LoopLatch));
+        return SinkAfter.find(V) != SinkAfter.end();
+      }))
+    return false;
+
   // Now we know the widest induction type, check if our found induction
   // is the same size. If it's not, unset it here and InnerLoopVectorizer
   // will create another.