Filler sizes have to be Smis, fix x64 breakage.

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 3278 matching lines @@
   if (new_dominator_size > Page::kMaxNonCodeHeapObjectSize) {
     if (FLAG_trace_allocation_folding) {
       PrintF("#%d (%s) cannot fold into #%d (%s) due to size: %d\n",
           id(), Mnemonic(), dominator_allocate->id(),
           dominator_allocate->Mnemonic(), new_dominator_size);
     }
     return;
   }
 
   HInstruction* new_dominator_size_constant = HConstant::CreateAndInsertBefore(
-      zone, context(), new_dominator_size, dominator_allocate);
+      zone,
+      context(),
+      new_dominator_size,
+      Representation::None(),
+      dominator_allocate);
   dominator_allocate->UpdateSize(new_dominator_size_constant);
 
 #ifdef VERIFY_HEAP
   if (FLAG_verify_heap && dominator_allocate->IsNewSpaceAllocation()) {
     dominator_allocate->MakePrefillWithFiller();
   }
 #endif
 
   // After that replace the dominated allocate instruction.
   HInstruction* dominated_allocate_instr =
@@ skipping 77 matching lines @@
 
 
 void HAllocate::UpdateFreeSpaceFiller(int32_t free_space_size) {
   ASSERT(filler_free_space_size_ != NULL);
   Zone* zone = block()->zone();
   HConstant* new_free_space_size = HConstant::CreateAndInsertBefore(
       zone,
       context(),
       filler_free_space_size_->value()->GetInteger32Constant() +
           free_space_size,
+      Representation::Smi(),

[Jakob Kummerow, 2013/08/27 11:43:34]

I'd like a comment here, please. Roughly:

We must explicitly force Smi representation for this constant, because on x64 we
would otherwise automatically choose int32, but the actual store requires a
Smi-tagged value.

       filler_free_space_size_);
   filler_free_space_size_->UpdateValue(new_free_space_size);
 }
 
 
 void HAllocate::CreateFreeSpaceFiller(int32_t free_space_size) {
   ASSERT(filler_free_space_size_ == NULL);
   Zone* zone = block()->zone();
   int32_t dominator_size =
       HConstant::cast(dominating_allocate_->size())->GetInteger32Constant();
   HInstruction* free_space_instr =
       HInnerAllocatedObject::New(zone, context(), dominating_allocate_,
       dominator_size, type());
   free_space_instr->InsertBefore(this);
   HConstant* filler_map = HConstant::New(
       zone,
       context(),
       isolate()->factory()->free_space_map(),
       UniqueValueId(isolate()->heap()->free_space_map()));
   filler_map->InsertAfter(free_space_instr);
   HInstruction* store_map = HStoreNamedField::New(zone, context(),
       free_space_instr, HObjectAccess::ForMap(), filler_map);
   store_map->SetFlag(HValue::kHasNoObservableSideEffects);
   store_map->InsertAfter(filler_map);
 
   HConstant* filler_size = HConstant::CreateAndInsertAfter(
-      zone, context(), free_space_size, store_map);
+      zone, context(), free_space_size, Representation::Smi(), store_map);

[Jakob Kummerow, 2013/08/27 11:43:34]

Consider repeating the comment here, or an abbreviated version:

// Must force Smi representation for x64 (see comment above).

   HObjectAccess access =
-      HObjectAccess::ForJSObjectOffset(FreeSpace::kSizeOffset);
+      HObjectAccess::ForJSObjectOffset(FreeSpace::kSizeOffset,
+          Representation::Smi());
   HStoreNamedField* store_size = HStoreNamedField::New(zone, context(),
       free_space_instr, access, filler_size);
   store_size->SetFlag(HValue::kHasNoObservableSideEffects);
   store_size->InsertAfter(filler_size);
   filler_free_space_size_ = store_size;
 }
 
 
 void HAllocate::PrintDataTo(StringStream* stream) {
   size()->PrintNameTo(stream);
@@ skipping 729 matching lines @@
       break;
     case kExternalMemory:
       stream->Add("[external-memory]");
       break;
   }
 
   stream->Add("@%d", offset());
 }
 
 } }  // namespace v8::internal