ARM: Add optimization for constant RHS in DoMulI.

src/arm/lithium-arm.cc

 // Copyright 2011 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 1394 matching lines @@
 }
 
 
 LInstruction* LChunkBuilder::DoMul(HMul* instr) {
   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* temp = NULL;
-    if (instr->CheckFlag(HValue::kBailoutOnMinusZero)) {
+    if (instr->CheckFlag(HValue::kBailoutOnMinusZero) &&
+        (instr->CheckFlag(HValue::kCanOverflow) ||
+        !right->IsConstantOperand())) {
       temp = TempRegister();
     }
-    LMulI* mul = new LMulI(left, right, temp);
-    return AssignEnvironment(DefineSameAsFirst(mul));
+    return AssignEnvironment(DefineSameAsFirst(new LMulI(left, right, temp)));
+
   } else if (instr->representation().IsDouble()) {
     return DoArithmeticD(Token::MUL, instr);
+
   } else {
     return DoArithmeticT(Token::MUL, instr);
   }
 }
 
 
 LInstruction* LChunkBuilder::DoSub(HSub* instr) {
   if (instr->representation().IsInteger32()) {
     ASSERT(instr->left()->representation().IsInteger32());
     ASSERT(instr->right()->representation().IsInteger32());
@@ skipping 800 matching lines @@
 
 LInstruction* LChunkBuilder::DoIn(HIn* instr) {
   LOperand* key = UseRegisterAtStart(instr->key());
   LOperand* object = UseRegisterAtStart(instr->object());
   LIn* result = new LIn(key, object);
   return MarkAsCall(DefineFixed(result, r0), instr);
 }
 
 
 } }  // namespace v8::internal