Index: lib/CodeGen/SelectionDAG/DAGCombiner.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -391,8 +391,8 @@
     SDValue FindBetterChain(SDNode *N, SDValue Chain);
 
     /// Do FindBetterChain for a store and any possibly adjacent stores on
-    /// consecutive chains.
-    bool findBetterNeighborChains(StoreSDNode *St);
+    /// consecutive chains. Return true if found a better chain for St.
+    bool findBetterNeighborChains(SDValue &Chain, StoreSDNode *St);
 
     /// Match "(X shl/srl V1) & V2" where V2 may not be present.
     bool MatchRotateHalf(SDValue Op, SDValue &Shift, SDValue &Mask);
@@ -12106,7 +12106,7 @@
 
     // Walk up chain skipping non-aliasing memory nodes, on this store and any
     // adjacent stores.
-    if (findBetterNeighborChains(ST)) {
+    if (findBetterNeighborChains(Chain, ST)) {
       // replaceStoreChain uses CombineTo, which handled all of the worklist
       // manipulation. Return the original node to not do anything else.
       return SDValue(ST, 0);
@@ -14909,7 +14909,7 @@
   return DAG.getNode(ISD::TokenFactor, SDLoc(N), MVT::Other, Aliases);
 }
 
-bool DAGCombiner::findBetterNeighborChains(StoreSDNode* St) {
+bool DAGCombiner::findBetterNeighborChains(SDValue &Chain, StoreSDNode *St) {
   // This holds the base pointer, index, and the offset in bytes from the base
   // pointer.
   BaseIndexOffset BasePtr = BaseIndexOffset::match(St->getBasePtr(), DAG);
@@ -14969,7 +14969,7 @@
     }
   }
 
-  bool MadeChange = false;
+  bool MakdeChangeToSt = false;
   SmallVector<std::pair<StoreSDNode *, SDValue>, 8> BetterChains;
 
   for (StoreSDNode *ChainedStore : ChainedStores) {
@@ -14977,7 +14977,8 @@
     SDValue BetterChain = FindBetterChain(ChainedStore, Chain);
 
     if (Chain != BetterChain) {
-      MadeChange = true;
+      if (ChainedStore == St)
+        MakdeChangeToSt = true;
       BetterChains.push_back(std::make_pair(ChainedStore, BetterChain));
     }
   }
@@ -14987,7 +14988,10 @@
   for (auto Replacement : BetterChains)
     replaceStoreChain(Replacement.first, Replacement.second);
 
-  return MadeChange;
+  if (!MakdeChangeToSt)
+    Chain = St->getChain();
+
+  return MakdeChangeToSt;
 }
 
 /// This is the entry point for the file.