Fix for performance issue 353661 - 23% regression in dromaeo.

src/ic.cc

Index: src/ic.cc
diff --git a/src/ic.cc b/src/ic.cc
index e17490406bfe6f660d85966ef1f9f4ef461e9b60..ff9ec1bb42a0e56183228b992254817f4f5b4a6c 100644
--- a/src/ic.cc
+++ b/src/ic.cc
@@ -1454,7 +1454,8 @@ Handle<Code> KeyedStoreIC::StoreElementStub(Handle<JSObject> receiver,
     if (IsTransitionStoreMode(store_mode)) {
       transitioned_receiver_map = ComputeTransitionedMap(receiver, store_mode);
     }
-    if (receiver_map.is_identical_to(previous_receiver_map) ||
+    if ((receiver_map.is_identical_to(previous_receiver_map) &&
+         IsTransitionStoreMode(store_mode)) ||
         IsTransitionOfMonomorphicTarget(
             MapToType<HeapType>(transitioned_receiver_map, isolate()))) {
       // If the "old" and "new" maps are in the same elements map family, or