Merge r8237 to V8 3.3 branch. Fix bug v8:1434, optimized compare of undefined can fail.

src/hydrogen-instructions.cc

 // 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 1213 matching lines @@
   stream->Add(" ");
   HBinaryOperation::PrintDataTo(stream);
 }
 
 
 void HCompare::SetInputRepresentation(Representation r) {
   input_representation_ = r;
   if (r.IsTagged()) {
     SetAllSideEffects();
     ClearFlag(kUseGVN);
+  } else if (r.IsDouble()) {
+    SetFlag(kDeoptimizeOnUndefined);
+    ClearAllSideEffects();
+    SetFlag(kUseGVN);
   } else {
     ClearAllSideEffects();
     SetFlag(kUseGVN);
   }
 }
 
 
 void HParameter::PrintDataTo(StringStream* stream) {
   stream->Add("%u", index());
 }
@@ skipping 515 matching lines @@
 
 
 void HCheckPrototypeMaps::Verify() {
   HInstruction::Verify();
   ASSERT(HasNoUses());
 }
 
 #endif
 
 } }  // namespace v8::internal