Do not explicitly record undetectable objects in the ToBoolean stub.

src/code-stubs.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 887 matching lines @@
 };
 
 
 class ToBooleanStub: public CodeStub {
  public:
   enum Type {
     UNDEFINED,
     BOOLEAN,
     NULL_TYPE,
     SMI,
-    UNDETECTABLE,
     SPEC_OBJECT,
     STRING,
     HEAP_NUMBER,
     INTERNAL_OBJECT,
     NUMBER_OF_TYPES
   };
 
+  // At most 8 different types can be distinguished, because the Code object
+  // only has room for a single byte to hold a set of these types. :-P
+  STATIC_ASSERT(NUMBER_OF_TYPES <= 8);
+
   class Types {
    public:
     Types() {}
-    explicit Types(int bits) : set_(bits) {}
+    explicit Types(byte bits) : set_(bits) {}
 
     bool IsEmpty() const { return set_.IsEmpty(); }
     bool Contains(Type type) const { return set_.Contains(type); }
     void Add(Type type) { set_.Add(type); }
-    int ToInt() const { return set_.ToIntegral(); }
+    byte ToByte() const { return set_.ToIntegral(); }
     void Print(StringStream* stream);
     void TraceTransition(Types to);
     bool Record(Handle<Object> object);
 
    private:
-    EnumSet<Type> set_;
+    EnumSet<Type, byte> set_;
   };
 
   explicit ToBooleanStub(Register tos, Types types = Types())
       : tos_(tos), types_(types) { }
 
   void Generate(MacroAssembler* masm);
   virtual int GetCodeKind() { return Code::TO_BOOLEAN_IC; }
   virtual void PrintName(StringStream* stream);
 
  private:
   Major MajorKey() { return ToBoolean; }
-  int MinorKey() { return (tos_.code() << NUMBER_OF_TYPES) | types_.ToInt(); }
+  int MinorKey() { return (tos_.code() << NUMBER_OF_TYPES) | types_.ToByte(); }
+
+  virtual void FinishCode(Code* code) {
+    code->set_to_boolean_state(types_.ToByte());
+  }
 
   void CheckOddball(MacroAssembler* masm,
                     Type type,
                     Handle<Object> value,
                     bool result,
                     Label* patch);
   void GenerateTypeTransition(MacroAssembler* masm);
 
   Register tos_;
   Types types_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_CODE_STUBS_H_