Only extend storage if FIELD

src/ia32/stub-cache-ia32.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 872 matching lines @@
     } else {
       __ fstp_d(FieldOperand(storage_reg, HeapNumber::kValueOffset));
     }
   }
 
   // Stub never generated for non-global objects that require access
   // checks.
   ASSERT(object->IsJSGlobalProxy() || !object->IsAccessCheckNeeded());
 
   // Perform map transition for the receiver if necessary.
-  if (object->map()->unused_property_fields() == 0) {
+  if (details.type() == FIELD &&
+      object->map()->unused_property_fields() == 0) {
     // The properties must be extended before we can store the value.
     // We jump to a runtime call that extends the properties array.
     __ pop(scratch1);  // Return address.
     __ push(receiver_reg);
     __ push(Immediate(transition));
     __ push(value_reg);
     __ push(scratch1);
     __ TailCallExternalReference(
         ExternalReference(IC_Utility(IC::kSharedStoreIC_ExtendStorage),
                           masm->isolate()),
@@ skipping 2847 matching lines @@
     TailCallBuiltin(masm, Builtins::kKeyedStoreIC_Slow);
   }
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32