Load elimination fix with a test case.

src/hydrogen-instructions.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 3557 matching lines @@
       HInnerAllocatedObject::New(zone, context(), dominating_allocate_,
       dominating_allocate_->size(), type());
   free_space_instr->InsertBefore(this);
   HConstant* filler_map = HConstant::New(
       zone,
       context(),
       isolate()->factory()->free_space_map());
   filler_map->FinalizeUniqueness();  // TODO(titzer): should be init'd a'ready
   filler_map->InsertAfter(free_space_instr);
   HInstruction* store_map = HStoreNamedField::New(zone, context(),
-      free_space_instr, HObjectAccess::ForMap(), filler_map);
+      free_space_instr, HObjectAccess::ForMap(), filler_map,
+      INITIALIZING_STORE);
   store_map->SetFlag(HValue::kHasNoObservableSideEffects);
   store_map->InsertAfter(filler_map);
 
   // We must explicitly force Smi representation here because on x64 we
   // would otherwise automatically choose int32, but the actual store
   // requires a Smi-tagged value.
   HConstant* filler_size = HConstant::CreateAndInsertAfter(
       zone, context(), free_space_size, Representation::Smi(), store_map);
   // Must force Smi representation for x64 (see comment above).
   HObjectAccess access =
       HObjectAccess::ForJSObjectOffset(FreeSpace::kSizeOffset,
           Representation::Smi());
   HStoreNamedField* store_size = HStoreNamedField::New(zone, context(),
-      free_space_instr, access, filler_size);
+      free_space_instr, access, filler_size, INITIALIZING_STORE);
   store_size->SetFlag(HValue::kHasNoObservableSideEffects);
   store_size->InsertAfter(filler_size);
   filler_free_space_size_ = store_size;
 }
 
 
 void HAllocate::ClearNextMapWord(int offset) {
   if (MustClearNextMapWord()) {
     Zone* zone = block()->zone();
     HObjectAccess access = HObjectAccess::ForJSObjectOffset(offset);
     HStoreNamedField* clear_next_map =
         HStoreNamedField::New(zone, context(), this, access,
-            block()->graph()->GetConstant0());
+            block()->graph()->GetConstant0(), INITIALIZING_STORE);
     clear_next_map->ClearAllSideEffects();
     clear_next_map->InsertAfter(this);
   }
 }
 
 
 void HAllocate::PrintDataTo(StringStream* stream) {
   size()->PrintNameTo(stream);
   stream->Add(" (");
   if (IsNewSpaceAllocation()) stream->Add("N");
@@ skipping 791 matching lines @@
       break;
     case kExternalMemory:
       stream->Add("[external-memory]");
       break;
   }
 
   stream->Add("@%d", offset());
 }
 
 } }  // namespace v8::internal