Index: lib/CodeGen/SelectionDAG/DAGCombiner.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -12844,7 +12844,19 @@
 
       // Check if we found a legal integer type that creates a meaningful merge.
       if (LastLegalType < 2 && LastLegalVectorType < 2) {
-        StoreNodes.erase(StoreNodes.begin(), StoreNodes.begin() + 1);
+        // We have already checked that candidate stores are in order
+        // and of correct shape. While there is no mergable sequence
+        // from the beggining one may start later in the sequence. The
+        // only reason a merge of size N could have failed where
+        // another of the same size would not have does not is if the
+        // alignment has improved. Drop as many candidates as we can
+        // here.
+        unsigned NumSkip = 1;
+        while ((NumSkip < NumConsecutiveStores) &&
+               (StoreNodes[NumSkip].MemNode->getAlignment() <= FirstStoreAlign))
+          NumSkip++;
+
+        StoreNodes.erase(StoreNodes.begin(), StoreNodes.begin() + NumSkip);
         continue;
       }
 
@@ -12900,6 +12912,23 @@
           NumStoresToMerge = i + 1;
       }
 
+      // Check if we found a legal integer type that creates a meaningful merge.
+      if (NumStoresToMerge < 2) {
+        // We have already checked that candidate stores are in order
+        // and of correct shape. While there is no mergable sequence
+        // from the beggining one may start later in the sequence. The
+        // only reason a merge of size N could have failed where
+        // another of the same size would not have does not is if the
+        // alignment has improved. Drop as many candidates as we can here.
+        unsigned NumSkip = 1;
+        while ((NumSkip < NumConsecutiveStores) &&
+               (StoreNodes[NumSkip].MemNode->getAlignment() <= FirstStoreAlign))
+          NumSkip++;
+
+        StoreNodes.erase(StoreNodes.begin(), StoreNodes.begin() + NumSkip);
+        continue;
+      }
+
       bool Merged = MergeStoresOfConstantsOrVecElts(
           StoreNodes, MemVT, NumStoresToMerge, false, true, false);
       if (!Merged) {