Fix HCheckValue::Canonicalize wrt uninitialized HConstant unique.

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 1548 matching lines @@
 
 
 void HCheckValue::PrintDataTo(StringStream* stream) {
   value()->PrintNameTo(stream);
   stream->Add(" ");
   object().handle()->ShortPrint(stream);
 }
 
 
 HValue* HCheckValue::Canonicalize() {
-  return (value()->IsConstant() &&
-          HConstant::cast(value())->GetUnique() == object_)
-      ? NULL
-      : this;
+  if (value()->IsConstant()) {
+    Unique<Object> unique = HConstant::cast(value())->GetUnique();

[titzer, 2014/03/03 12:42:38]

Can you move this logic into a method on HConstant instead, e.g. EqualsUnique()
?

+    if (unique.IsInitialized() && unique == object_) return NULL;
+  }
+  return this;
 }
 
 
 const char* HCheckInstanceType::GetCheckName() {
   switch (check_) {
     case IS_SPEC_OBJECT: return "object";
     case IS_JS_ARRAY: return "array";
     case IS_STRING: return "string";
     case IS_INTERNALIZED_STRING: return "internalized_string";
   }
@@ skipping 2940 matching lines @@
       break;
     case kExternalMemory:
       stream->Add("[external-memory]");
       break;
   }
 
   stream->Add("@%d", offset());
 }
 
 } }  // namespace v8::internal