Move swapping of operands for commutative binary operations to the lithium IR...

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
===================================================================
--- src/hydrogen-instructions.h	(revision 6458)
+++ src/hydrogen-instructions.h	(working copy)
@@ -1871,19 +1871,6 @@
   HValue* left() const { return OperandAt(0); }
   HValue* right() const { return OperandAt(1); }
 
-  // TODO(kasperl): Move these helpers to the IA-32 Lithium
-  // instruction sequence builder.
-  HValue* LeastConstantOperand() const {
-    if (IsCommutative() && left()->IsConstant()) return right();
-    return left();
-  }
-  HValue* MostConstantOperand() const {
-    if (IsCommutative() && left()->IsConstant()) return left();
-    return right();
-  }
-
-  virtual bool IsCommutative() const { return false; }
-
   virtual void PrintDataTo(StringStream* stream) const;
   virtual int OperandCount() const { return operands_.length(); }
   virtual HValue* OperandAt(int index) const { return operands_[index]; }
@@ -2335,12 +2322,6 @@
     SetFlag(kCanOverflow);
   }
 
-  // Add is only commutative if two integer values are added and not if two
-  // tagged values are added (because it might be a String concatenation).
-  virtual bool IsCommutative() const {
-    return !representation().IsTagged();
-  }
-
   virtual HValue* EnsureAndPropagateNotMinusZero(BitVector* visited);
 
   virtual HType CalculateInferredType() const;
@@ -2375,11 +2356,6 @@
 
   virtual HValue* EnsureAndPropagateNotMinusZero(BitVector* visited);
 
-  // Only commutative if it is certain that not two objects are multiplicated.
-  virtual bool IsCommutative() const {
-    return !representation().IsTagged();
-  }
-
   DECLARE_CONCRETE_INSTRUCTION(Mul, "mul")
 
  protected:
@@ -2423,7 +2399,6 @@
   HBitAnd(HValue* left, HValue* right)
       : HBitwiseBinaryOperation(left, right) { }
 
-  virtual bool IsCommutative() const { return true; }
   virtual HType CalculateInferredType() const;
 
   DECLARE_CONCRETE_INSTRUCTION(BitAnd, "bit_and")
@@ -2438,7 +2413,6 @@
   HBitXor(HValue* left, HValue* right)
       : HBitwiseBinaryOperation(left, right) { }
 
-  virtual bool IsCommutative() const { return true; }
   virtual HType CalculateInferredType() const;
 
   DECLARE_CONCRETE_INSTRUCTION(BitXor, "bit_xor")
@@ -2450,7 +2424,6 @@
   HBitOr(HValue* left, HValue* right)
       : HBitwiseBinaryOperation(left, right) { }
 
-  virtual bool IsCommutative() const { return true; }
   virtual HType CalculateInferredType() const;
 
   DECLARE_CONCRETE_INSTRUCTION(BitOr, "bit_or")