SLPVectorizer: fix wrong scheduling of atomic load/stores.

This fixes PR22306.

llvm-svn: 227077

1 files changed, 12 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index fb1f64ba14a..4dee2d92a16 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -309,6 +309,17 @@ static AliasAnalysis::Location getLocation(Instruction *I, AliasAnalysis *AA) {
   return AliasAnalysis::Location();
 }
 
+/// \returns True if the instruction is not a volatile or atomic load/store.
+static bool isSimple(Instruction *I) {
+  if (LoadInst *LI = dyn_cast<LoadInst>(I))
+    return LI->isSimple();
+  if (StoreInst *SI = dyn_cast<StoreInst>(I))
+    return SI->isSimple();
+  if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(I))
+    return !MI->isVolatile();
+  return true;
+}
+
 /// Bottom Up SLP Vectorizer.
 class BoUpSLP {
 public:
@@ -501,7 +512,7 @@ private:
     }
     AliasAnalysis::Location Loc2 = getLocation(Inst2, AA);
     bool aliased = true;
-    if (Loc1.Ptr && Loc2.Ptr) {
+    if (Loc1.Ptr && Loc2.Ptr && isSimple(Inst1) && isSimple(Inst2)) {
       // Do the alias check.
       aliased = AA->alias(Loc1, Loc2);
     }