Harmony: optimize Math.clz32.

src/hydrogen-instructions.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 2582 matching lines @@
       switch (op_) {
         case kMathFloor:
         case kMathRound:
         case kMathSqrt:
         case kMathPowHalf:
         case kMathLog:
         case kMathExp:
           return Representation::Double();
         case kMathAbs:
           return representation();
+        case kMathClz32:
+          return Representation::Integer32();
         default:
           UNREACHABLE();
           return Representation::None();
       }
     }
   }
 
   virtual Range* InferRange(Zone* zone) V8_OVERRIDE;
 
   virtual HValue* Canonicalize() V8_OVERRIDE;
@@ skipping 11 matching lines @@
   }
 
  private:
   HUnaryMathOperation(HValue* context, HValue* value, BuiltinFunctionId op)
       : HTemplateInstruction<2>(HType::TaggedNumber()), op_(op) {
     SetOperandAt(0, context);
     SetOperandAt(1, value);
     switch (op) {
       case kMathFloor:
       case kMathRound:
+      case kMathClz32:
         set_representation(Representation::Integer32());
         break;
       case kMathAbs:
         // Not setting representation here: it is None intentionally.
         SetFlag(kFlexibleRepresentation);
         // TODO(svenpanne) This flag is actually only needed if representation()
         // is tagged, and not when it is an unboxed double or unboxed integer.
         SetChangesFlag(kNewSpacePromotion);
         break;
       case kMathLog:
@@ skipping 4872 matching lines @@
   virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_