Require smi for keyed store to smi.

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index bf05619fbf228bb95f6aaa321bf268b57fe63673..5a261ed77296ccda974c6ae44e7d8158228daed2 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -5723,6 +5723,9 @@ class HStoreKeyed
     } else if (IsFastDoubleElementsKind(elements_kind)) {
       SetGVNFlag(kChangesDoubleArrayElements);
       SetFlag(kDeoptimizeOnUndefined);
+    } else if (IsFastSmiElementsKind(elements_kind)) {
+      SetGVNFlag(kChangesArrayElements);
+      SetFlag(kDeoptimizeOnUndefined);
     } else {
       SetGVNFlag(kChangesArrayElements);
     }
@@ -5751,6 +5754,10 @@ class HStoreKeyed
       return Representation::Double();
     }
 
+    if (IsFastSmiElementsKind(elements_kind())) {
+      return Representation::Smi();
+    }
+
     return is_external() ? Representation::Integer32()
                          : Representation::Tagged();
   }