Track whether a node or variable are likely to be a Smi value. Propagate that...

src/rewriter.h

 // Copyright 2006-2008 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 26 matching lines @@
 //
 // The rewriter adds a (hidden) variable, called .result, to the
 // activation, and tries to figure out where it needs to store into
 // this variable. If the variable is ever used, we conclude by adding
 // a return statement that returns the variable to the body of the
 // given function.
 
 class Rewriter {
  public:
   static bool Process(FunctionLiteral* function);
+  static void Optimize(FunctionLiteral* function);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_REWRITER_H_