Use existing global cell status as a hint when generating loads.

src/ic.cc

 // Copyright 2006-2009 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 281 matching lines @@
   ClearInlinedVersion(address);
   SetTargetAtAddress(address, initialize_stub());
 }
 
 
 void LoadIC::ClearInlinedVersion(Address address) {
   // Reset the map check of the inlined inobject property load (if
   // present) to guarantee failure by holding an invalid map (the null
   // value).  The offset can be patched to anything.
   PatchInlinedLoad(address, Heap::null_value(), 0);
-  PatchInlinedContextualLoad(address, Heap::null_value(), Heap::null_value());
+  PatchInlinedContextualLoad(address,
+                             Heap::null_value(),
+                             Heap::null_value(),
+                             true);
 }
 
 
 void LoadIC::Clear(Address address, Code* target) {
   if (target->ic_state() == UNINITIALIZED) return;
   ClearInlinedVersion(address);
   SetTargetAtAddress(address, initialize_stub());
 }
 
 
@@ skipping 528 matching lines @@
                        name);
       }
     } else {
       TRACE_IC_NAMED("[LoadIC : no inline patch %s (not inobject)]\n", name);
     }
   } else if (can_be_inlined_contextual) {
     Map* map = lookup.holder()->map();
     JSGlobalPropertyCell* cell = JSGlobalPropertyCell::cast(
         lookup.holder()->property_dictionary()->ValueAt(
             lookup.GetDictionaryEntry()));
-    if (PatchInlinedContextualLoad(address(), map, cell)) {
+    if (PatchInlinedContextualLoad(address(),
+                                   map,
+                                   cell,
+                                   lookup.IsDontDelete())) {
       set_target(megamorphic_stub());
       TRACE_IC_NAMED("[LoadIC : inline contextual patch %s]\n", name);
       ASSERT(cell->value() != Heap::the_hole_value());
       return cell->value();
     }
   } else {
     if (FLAG_use_ic && state == PREMONOMORPHIC) {
       TRACE_IC_NAMED("[LoadIC : no inline patch %s (not inlinable)]\n", name);
     }
   }
@@ skipping 971 matching lines @@
 #undef ADDR
 };
 
 
 Address IC::AddressFromUtilityId(IC::UtilityId id) {
   return IC_utilities[id];
 }
 
 
 } }  // namespace v8::internal