Don't emit a write barrier when storing boolean-typed values.

src/hydrogen-instructions.h

 // Copyright 2011 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 3344 matching lines @@
     HLoadContextSlot* b = HLoadContextSlot::cast(other);
     return (slot_index() == b->slot_index());
   }
 
  private:
   int slot_index_;
 };
 
 
 static inline bool StoringValueNeedsWriteBarrier(HValue* value) {
-  return !value->type().IsSmi() &&
-      !(value->IsConstant() && HConstant::cast(value)->InOldSpace());
+  return !value->type().IsBoolean()
+      && !value->type().IsSmi()

[Kevin Millikin (Chromium), 2011/07/07 10:13:44]

OK.  The predicate here would be easier to read if it was negated, but maybe
that's less good at the call sites.

+      && !(value->IsConstant() && HConstant::cast(value)->InOldSpace());
 }
 
 
 class HStoreContextSlot: public HTemplateInstruction<2> {
  public:
   HStoreContextSlot(HValue* context, int slot_index, HValue* value)
       : slot_index_(slot_index) {
     SetOperandAt(0, context);
     SetOperandAt(1, value);
     SetFlag(kChangesContextSlots);
@@ skipping 775 matching lines @@
 
   DECLARE_CONCRETE_INSTRUCTION(In)
 };
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_