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

src/arm/lithium-arm.cc

Index: src/arm/lithium-arm.cc
===================================================================
--- src/arm/lithium-arm.cc	(revision 6458)
+++ src/arm/lithium-arm.cc	(working copy)
@@ -730,8 +730,12 @@
   ASSERT(instr->left()->representation().IsInteger32());
   ASSERT(instr->right()->representation().IsInteger32());
 
-  LOperand* left = UseRegisterAtStart(instr->LeastConstantOperand());
-  LOperand* right = UseOrConstantAtStart(instr->MostConstantOperand());
+  LOperand* left = UseRegisterAtStart(instr->left()->IsConstant()
+                                      ? instr->right()
+                                      : instr->left());
+  LOperand* right = UseOrConstantAtStart(instr->left()->IsConstant()
+                                         ? instr->left()
+                                         : instr->right());
   return DefineSameAsFirst(new LBitI(op, left, right));
 }
 
@@ -1274,8 +1278,12 @@
   if (instr->representation().IsInteger32()) {
     ASSERT(instr->left()->representation().IsInteger32());
     ASSERT(instr->right()->representation().IsInteger32());
-    LOperand* left = UseRegisterAtStart(instr->LeastConstantOperand());
-    LOperand* right = UseOrConstant(instr->MostConstantOperand());
+    LOperand* left = UseRegisterAtStart(instr->left()->IsConstant()
+                                        ? instr->right()
+                                        : instr->left());
+    LOperand* right = UseOrConstant(instr->left()->IsConstant()
+                                    ? instr->left()
+                                    : instr->right());
     LOperand* temp = NULL;
     if (instr->CheckFlag(HValue::kBailoutOnMinusZero)) {
       temp = TempRegister();
@@ -1314,8 +1322,12 @@
   if (instr->representation().IsInteger32()) {
     ASSERT(instr->left()->representation().IsInteger32());
     ASSERT(instr->right()->representation().IsInteger32());
-    LOperand* left = UseRegisterAtStart(instr->LeastConstantOperand());
-    LOperand* right = UseOrConstantAtStart(instr->MostConstantOperand());
+    LOperand* left = UseRegisterAtStart(instr->left()->IsConstant()
+                                        ? instr->right()
+                                        : instr->left());
+    LOperand* right = UseOrConstantAtStart(instr->left()->IsConstant()
+                                           ? instr->left()
+                                           : instr->right());
     LAddI* add = new LAddI(left, right);
     LInstruction* result = DefineSameAsFirst(add);
     if (instr->CheckFlag(HValue::kCanOverflow)) {