emit premonomorphic ics for loads/stores in optimized code

src/ic/ic.cc

Index: src/ic/ic.cc
diff --git a/src/ic/ic.cc b/src/ic/ic.cc
index 537b18324d6868e29b5a494090f0b4cad59e4e26..25142632e6c54c7aa1a23c592933f723785d0916 100644
--- a/src/ic/ic.cc
+++ b/src/ic/ic.cc
@@ -982,10 +982,13 @@ Handle<Code> LoadIC::initialize_stub(Isolate* isolate,
 
 
 Handle<Code> LoadIC::initialize_stub_in_optimized_code(
-    Isolate* isolate, ExtraICState extra_state) {
+    Isolate* isolate, ExtraICState extra_state, bool initialize_megamorphic) {
   if (FLAG_vector_ics) {
     return VectorLoadStub(isolate, LoadICState(extra_state)).GetCode();
   }
+  if (initialize_megamorphic) {
+    return PropertyICCompiler::ComputeLoad(isolate, MEGAMORPHIC, extra_state);
+  }
   return initialize_stub(isolate, extra_state);
 }
 
@@ -1606,10 +1609,12 @@ Handle<Code> CallIC::initialize_stub_in_optimized_code(
 
 
 Handle<Code> StoreIC::initialize_stub(Isolate* isolate,
-                                      LanguageMode language_mode) {
+                                      LanguageMode language_mode,
+                                      bool initialize_megamorphic) {
   ExtraICState extra_state = ComputeExtraICState(language_mode);
+  InlineCacheState state = initialize_megamorphic ? MEGAMORPHIC : UNINITIALIZED;
   Handle<Code> ic =
-      PropertyICCompiler::ComputeStore(isolate, UNINITIALIZED, extra_state);
+      PropertyICCompiler::ComputeStore(isolate, state, extra_state);
   return ic;
 }