Allow constants to be deleted by reinserting them into the graph as needed.

src/code-stubs-hydrogen.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 132 matching lines @@
     isolate()->GetHTracer()->TraceCompilation(&info_);
   }
 
   int param_count = descriptor_->register_param_count_;
   HEnvironment* start_environment = graph()->start_environment();
   HBasicBlock* next_block = CreateBasicBlock(start_environment);
   current_block()->Goto(next_block);
   next_block->SetJoinId(BailoutId::StubEntry());
   set_current_block(next_block);
 
-  HConstant* undefined_constant =
-      Add<HConstant>(isolate()->factory()->undefined_value());
-  graph()->set_undefined_constant(undefined_constant);
-
   for (int i = 0; i < param_count; ++i) {
     HParameter* param =
         Add<HParameter>(i, HParameter::REGISTER_PARAMETER);
     start_environment->Bind(i, param);
     parameters_[i] = param;
   }
 
   HInstruction* stack_parameter_count;
   if (descriptor_->stack_parameter_count_.is_valid()) {
     ASSERT(descriptor_->environment_length() == (param_count + 1));
@@ skipping 1075 matching lines @@
   return js_function;
 }
 
 
 Handle<Code> FastNewClosureStub::GenerateCode(Isolate* isolate) {
   return DoGenerateCode(isolate, this);
 }
 
 
 } }  // namespace v8::internal