X64: Ensure that unary subtraction returns a zero-extended smi, if it returns...

src/x64/codegen-x64.cc

 // Copyright 2009 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 6302 matching lines @@
   Label try_float;
   Label special;
   // Check whether the value is a smi.
   __ JumpIfNotSmi(rax, &try_float);
 
   // Enter runtime system if the value of the smi is zero
   // to make sure that we switch between 0 and -0.
   // Also enter it if the value of the smi is Smi::kMinValue
   __ testl(rax, Immediate(0x7FFFFFFE));
   __ j(zero, &special);
-  __ neg(rax);
+  __ negl(rax);
   __ jmp(&done);
 
   __ bind(&special);
   // Either zero or -0x4000000, neither of which become a smi when negated.
   __ testl(rax, rax);
   __ j(not_zero, &slow);
   __ Move(rax, Factory::minus_zero_value());
   __ jmp(&done);
 
   // Enter runtime system.
@@ skipping 1349 matching lines @@
 int CompareStub::MinorKey() {
   // Encode the two parameters in a unique 16 bit value.
   ASSERT(static_cast<unsigned>(cc_) < (1 << 15));
   return (static_cast<unsigned>(cc_) << 1) | (strict_ ? 1 : 0);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal