tweak of Math.abs in its x64 stub

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 3431 matching lines @@
   Register input_reg = ToRegister(instr->value());
   __ testl(input_reg, input_reg);
   Label is_positive;
   __ j(not_sign, &is_positive, Label::kNear);
   __ negl(input_reg);  // Sets flags.
   DeoptimizeIf(negative, instr->environment());
   __ bind(&is_positive);
 }
 
 
-void LCodeGen::EmitInteger64MathAbs(LMathAbs* instr) {
+void LCodeGen::EmitSmiMathAbs(LMathAbs* instr) {
   Register input_reg = ToRegister(instr->value());
   __ testq(input_reg, input_reg);
   Label is_positive;
   __ j(not_sign, &is_positive, Label::kNear);
   __ neg(input_reg);  // Sets flags.
   DeoptimizeIf(negative, instr->environment());
   __ bind(&is_positive);
 }
 
 
@@ skipping 16 matching lines @@
 
   if (r.IsDouble()) {
     XMMRegister scratch = xmm0;
     XMMRegister input_reg = ToDoubleRegister(instr->value());
     __ xorps(scratch, scratch);
     __ subsd(scratch, input_reg);
     __ andpd(input_reg, scratch);
   } else if (r.IsInteger32()) {
     EmitIntegerMathAbs(instr);
   } else if (r.IsSmi()) {
-    EmitInteger64MathAbs(instr);
+    EmitSmiMathAbs(instr);
   } else {  // Tagged case.
     DeferredMathAbsTaggedHeapNumber* deferred =
         new(zone()) DeferredMathAbsTaggedHeapNumber(this, instr);
     Register input_reg = ToRegister(instr->value());
     // Smi check.
     __ JumpIfNotSmi(input_reg, deferred->entry());
-    __ SmiToInteger32(input_reg, input_reg);
-    EmitIntegerMathAbs(instr);
-    __ Integer32ToSmi(input_reg, input_reg);
+    EmitSmiMathAbs(instr);
     __ bind(deferred->exit());
   }
 }
 
 
 void LCodeGen::DoMathFloor(LMathFloor* instr) {
   XMMRegister xmm_scratch = xmm0;
   Register output_reg = ToRegister(instr->result());
   XMMRegister input_reg = ToDoubleRegister(instr->value());
 
@@ skipping 2108 matching lines @@
                                FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64