Optimistically assume that elements IC only transition once.

src/ic.h

 // 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 433 matching lines @@
       KeyedAccessGrowMode grow_mode) = 0;
 
   Handle<Code> ComputeMonomorphicStubWithoutMapCheck(
       Handle<Map> receiver_map,
       StrictModeFlag strict_mode,
       KeyedAccessGrowMode grow_mode);
 
  private:
   void GetReceiverMapsForStub(Handle<Code> stub, MapHandleList* result);
 
-  Handle<Code> ComputeMonomorphicStub(Handle<JSObject> receiver,
+  Handle<Code> ComputeMonomorphicStub(Handle<Map> receiver_map,
                                       StubKind stub_kind,
                                       StrictModeFlag strict_mode,
                                       Handle<Code> default_stub);
 
   Handle<Map> ComputeTransitionedMap(Handle<JSObject> receiver,
                                      StubKind stub_kind);
 
   static bool IsTransitionStubKind(StubKind stub_kind) {
     return stub_kind > STORE_NO_TRANSITION &&
         stub_kind != STORE_AND_GROW_NO_TRANSITION;
   }
 
   static bool IsGrowStubKind(StubKind stub_kind) {
     return stub_kind >= STORE_AND_GROW_NO_TRANSITION;
   }
+
+  static StubKind GetNoTransitionStubKind(StubKind stub_kind) {
+    if (!IsTransitionStubKind(stub_kind)) return stub_kind;
+    if (IsGrowStubKind(stub_kind)) return STORE_AND_GROW_NO_TRANSITION;
+    return STORE_NO_TRANSITION;
+  }
 };
 
 
 class KeyedLoadIC: public KeyedIC {
  public:
   explicit KeyedLoadIC(Isolate* isolate) : KeyedIC(isolate) {
     ASSERT(target()->is_keyed_load_stub());
   }
 
   MUST_USE_RESULT MaybeObject* Load(State state,
@@ skipping 351 matching lines @@
 };
 
 
 // Helper for BinaryOpIC and CompareIC.
 enum InlinedSmiCheck { ENABLE_INLINED_SMI_CHECK, DISABLE_INLINED_SMI_CHECK };
 void PatchInlinedSmiCode(Address address, InlinedSmiCheck check);
 
 } }  // namespace v8::internal
 
 #endif  // V8_IC_H_