Harmony: optimize Math.clz32.

src/a64/lithium-a64.h

Index: src/a64/lithium-a64.h
diff --git a/src/a64/lithium-a64.h b/src/a64/lithium-a64.h
index 33d11e6c5d8a9e3d14343d3c4c9ad0e24e07ed1f..59ae9be62139128fcd838ce9d74cfe2978ff68a1 100644
--- a/src/a64/lithium-a64.h
+++ b/src/a64/lithium-a64.h
@@ -130,6 +130,7 @@ class LCodeGen;
   V(MapEnumLength)                              \
   V(MathAbs)                                    \
   V(MathAbsTagged)                              \
+  V(MathClz32)                                  \
   V(MathExp)                                    \
   V(MathFloor)                                  \
   V(MathFloorOfDiv)                             \
@@ -1906,6 +1907,13 @@ class LMathLog V8_FINAL : public LUnaryMathOperation<0> {
 };
 
 
+class LMathClz32 V8_FINAL : public LUnaryMathOperation<0> {
+ public:
+  explicit LMathClz32(LOperand* value) : LUnaryMathOperation<0>(value) { }
+  DECLARE_CONCRETE_INSTRUCTION(MathClz32, "math-clz32")
+};
+
+
 class LMathMinMax V8_FINAL : public LTemplateInstruction<1, 2, 0> {
  public:
   LMathMinMax(LOperand* left, LOperand* right) {