Perform string add in generated code on X64 platform...

src/ia32/codegen-ia32.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 742 matching lines @@
     string_check_ = ((flags & NO_STRING_CHECK_IN_STUB) == 0);
   }
 
  private:
   Major MajorKey() { return StringAdd; }
   int MinorKey() { return string_check_ ? 0 : 1; }
 
   void Generate(MacroAssembler* masm);
 
   void GenerateCopyCharacters(MacroAssembler* masm,
-                                   Register desc,
-                                   Register src,
-                                   Register count,
-                                   Register scratch,
-                                   bool ascii);
+                              Register desc,
+                              Register src,
+                              Register count,
+                              Register scratch,
+                              bool ascii);
 
   // Should the stub check whether arguments are strings?
   bool string_check_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_IA32_CODEGEN_IA32_H_