[DAGCombiner] Don't add volatile or indexed stores to ChainedStores

Summary:
findBetterNeighborChains does not handle volatile or indexed stores.
However, it did not check when adding stores to ChainedStores.

Reviewers: arsenm

Differential Revision: http://reviews.llvm.org/D16463

llvm-svn: 259024

1 files changed, 4 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 35801474e1c..fea77d0f216 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -14756,6 +14756,10 @@ bool DAGCombiner::findBetterNeighborChains(StoreSDNode* St) {
     while (true) {
       if (StoreSDNode *STn = dyn_cast<StoreSDNode>(NextInChain)) {
         // We found a store node. Use it for the next iteration.
+        if (STn->isVolatile() || STn->isIndexed()) {
+          Index = nullptr;
+          break;
+        }
         ChainedStores.push_back(STn);
         Index = STn;
         break;