Replace OS::MemCopy with OS::MemMove (just as fast but more flexible).

src/x64/lithium-codegen-x64.cc

 // Copyright 2013 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 100 matching lines @@
   StringBuilder builder(buffer, ARRAY_SIZE(buffer));
   va_list arguments;
   va_start(arguments, format);
   builder.AddFormattedList(format, arguments);
   va_end(arguments);
 
   // Copy the string before recording it in the assembler to avoid
   // issues when the stack allocated buffer goes out of scope.
   int length = builder.position();
   Vector<char> copy = Vector<char>::New(length + 1);
-  memcpy(copy.start(), builder.Finalize(), copy.length());
+  OS::MemCopy(copy.start(), builder.Finalize(), copy.length());
   masm()->RecordComment(copy.start());
 }
 
 
 bool LCodeGen::GeneratePrologue() {
   ASSERT(is_generating());
 
   if (info()->IsOptimizing()) {
     ProfileEntryHookStub::MaybeCallEntryHook(masm_);
 
@@ skipping 5522 matching lines @@
                                FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64