1 files changed, 12 insertions, 6 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index f07bfd88019..54d348e8911 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -392,8 +392,12 @@ namespace {
     /// chain (aliasing node.)
     SDValue FindBetterChain(SDNode *N, SDValue Chain);
 
-    /// Do FindBetterChain for a store and any possibly adjacent stores on
-    /// consecutive chains.
+    /// Try to replace a store and any possibly adjacent stores on
+    /// consecutive chains with better chains. Return true only if St is
+    /// replaced.
+    ///
+    /// Notice that other chains may still be replaced even if the function
+    /// returns false.
     bool findBetterNeighborChains(StoreSDNode *St);
 
     /// Match "(X shl/srl V1) & V2" where V2 may not be present.
@@ -12102,6 +12106,7 @@ SDValue DAGCombiner::visitSTORE(SDNode *N) {
       // manipulation. Return the original node to not do anything else.
       return SDValue(ST, 0);
     }
+    Chain = ST->getChain();
   }
 
   // Try transforming N to an indexed store.
@@ -14950,7 +14955,7 @@ SDValue DAGCombiner::FindBetterChain(SDNode *N, SDValue OldChain) {
   return DAG.getNode(ISD::TokenFactor, SDLoc(N), MVT::Other, Aliases);
 }
 
-bool DAGCombiner::findBetterNeighborChains(StoreSDNode* St) {
+bool DAGCombiner::findBetterNeighborChains(StoreSDNode *St) {
   // This holds the base pointer, index, and the offset in bytes from the base
   // pointer.
   BaseIndexOffset BasePtr = BaseIndexOffset::match(St->getBasePtr(), DAG);
@@ -15010,7 +15015,7 @@ bool DAGCombiner::findBetterNeighborChains(StoreSDNode* St) {
     }
   }
 
-  bool MadeChange = false;
+  bool MadeChangeToSt = false;
   SmallVector<std::pair<StoreSDNode *, SDValue>, 8> BetterChains;
 
   for (StoreSDNode *ChainedStore : ChainedStores) {
@@ -15018,7 +15023,8 @@ bool DAGCombiner::findBetterNeighborChains(StoreSDNode* St) {
     SDValue BetterChain = FindBetterChain(ChainedStore, Chain);
 
     if (Chain != BetterChain) {
-      MadeChange = true;
+      if (ChainedStore == St)
+        MadeChangeToSt = true;
       BetterChains.push_back(std::make_pair(ChainedStore, BetterChain));
     }
   }
@@ -15028,7 +15034,7 @@ bool DAGCombiner::findBetterNeighborChains(StoreSDNode* St) {
   for (auto Replacement : BetterChains)
     replaceStoreChain(Replacement.first, Replacement.second);
 
-  return MadeChange;
+  return MadeChangeToSt;
 }
 
 /// This is the entry point for the file.