Port inlined quick equality check for non-NaN to x64.

src/ia32/codegen-ia32.cc

 // Copyright 2010 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 2755 matching lines @@
 
       // Inline number comparison.
       if (inline_number_compare) {
         GenerateInlineNumberComparison(&left_side, &right_side, cc, dest);
       }
 
       // End of in-line compare, call out to the compare stub. Don't include
       // number comparison in the stub if it was inlined.
       CompareStub stub(cc, strict, nan_info, !inline_number_compare);
       Result answer = frame_->CallStub(&stub, &left_side, &right_side);
-      if (cc == equal) {
-        __ test(answer.reg(), Operand(answer.reg()));
-      } else {
-        __ cmp(answer.reg(), 0);
-      }
+      __ test(answer.reg(), Operand(answer.reg()));
       answer.Unuse();
       dest->Split(cc);
     } else {
       // Here we split control flow to the stub call and inlined cases
       // before finally splitting it to the control destination.  We use
       // a jump target and branching to duplicate the virtual frame at
       // the first split.  We manually handle the off-frame references
       // by reconstituting them on the non-fall-through path.
       JumpTarget is_smi;
       Register left_reg = left_side.reg();
@@ skipping 10129 matching lines @@
 
   // Call the runtime; it returns -1 (less), 0 (equal), or 1 (greater)
   // tagged as a small integer.
   __ bind(&runtime);
   __ TailCallRuntime(Runtime::kStringCompare, 2, 1);
 }
 
 #undef __
 
 } }  // namespace v8::internal