SLPVectorizer: Don't vectorize volatile memory operations

radar://15231682

Reapply r192799,
  http://lab.llvm.org:8011/builders/lldb-x86_64-debian-clang/builds/8226
showed that the bot is still broken even with this out.

llvm-svn: 192820

1 files changed, 8 insertions, 3 deletions

diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index af1c0e74236..4d82bc428db 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -786,13 +786,14 @@ void BoUpSLP::buildTree_rec(ArrayRef<Value *> VL, unsigned Depth) {
     }
     case Instruction::Load: {
       // Check if the loads are consecutive or of we need to swizzle them.
-      for (unsigned i = 0, e = VL.size() - 1; i < e; ++i)
-        if (!isConsecutiveAccess(VL[i], VL[i + 1])) {
+      for (unsigned i = 0, e = VL.size() - 1; i < e; ++i) {
+        LoadInst *L = cast<LoadInst>(VL[i]);
+        if (!L->isSimple() || !isConsecutiveAccess(VL[i], VL[i + 1])) {
           newTreeEntry(VL, false);
           DEBUG(dbgs() << "SLP: Need to swizzle loads.\n");
           return;
         }
-
+      }
       newTreeEntry(VL, true);
       DEBUG(dbgs() << "SLP: added a vector of loads.\n");
       return;
@@ -1911,6 +1912,10 @@ unsigned SLPVectorizer::collectStores(BasicBlock *BB, BoUpSLP &R) {
     if (!SI)
       continue;
 
+    // Don't touch volatile stores.
+    if (!SI->isSimple())
+      continue;
+
     // Check that the pointer points to scalars.
     Type *Ty = SI->getValueOperand()->getType();
     if (Ty->isAggregateType() || Ty->isVectorTy())