Tweak register allocation for Math.round and do not use roundsd.

src/ia32/lithium-ia32.h

 // Copyright 2012 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 114 matching lines @@
   V(LoadKeyed)                                  \
   V(LoadKeyedGeneric)                           \
   V(LoadNamedField)                             \
   V(LoadNamedFieldPolymorphic)                  \
   V(LoadNamedGeneric)                           \
   V(MapEnumLength)                              \
   V(MathExp)                                    \
   V(MathFloorOfDiv)                             \
   V(MathMinMax)                                 \
   V(MathPowHalf)                                \
+  V(MathRound)                                  \
   V(ModI)                                       \
   V(MulI)                                       \
   V(NumberTagD)                                 \
   V(NumberTagI)                                 \
   V(NumberTagU)                                 \
   V(NumberUntagD)                               \
   V(ObjectLiteral)                              \
   V(OsrEntry)                                   \
   V(OuterContext)                               \
   V(Parameter)                                  \
@@ skipping 548 matching lines @@
   LOperand* context() { return inputs_[1]; }
   LOperand* value() { return inputs_[0]; }
   LOperand* temp() { return temps_[0]; }
 
   DECLARE_CONCRETE_INSTRUCTION(MathPowHalf, "math-pow-half")
 
   virtual void PrintDataTo(StringStream* stream);
 };
 
 
+class LMathRound: public LTemplateInstruction<1, 2, 1> {
+ public:
+  LMathRound(LOperand* context, LOperand* value, LOperand* temp) {
+    inputs_[1] = context;
+    inputs_[0] = value;
+    temps_[0] = temp;
+  }
+
+  LOperand* context() { return inputs_[1]; }
+  LOperand* value() { return inputs_[0]; }
+  LOperand* temp() { return temps_[0]; }
+
+  DECLARE_CONCRETE_INSTRUCTION(MathRound, "math-round")
+  DECLARE_HYDROGEN_ACCESSOR(UnaryMathOperation)
+
+  virtual void PrintDataTo(StringStream* stream);
+};
+
+
 class LCmpObjectEqAndBranch: public LControlInstruction<2, 0> {
  public:
   LCmpObjectEqAndBranch(LOperand* left, LOperand* right) {
     inputs_[0] = left;
     inputs_[1] = right;
   }
 
   LOperand* left() { return inputs_[0]; }
   LOperand* right() { return inputs_[1]; }
 
@@ skipping 2076 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(LChunkBuilder);
 };
 
 #undef DECLARE_HYDROGEN_ACCESSOR
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_IA32_LITHIUM_IA32_H_