[turbofan] Turn Math.clz32 into an inlinable builtin.

test/unittests/compiler/js-intrinsic-lowering-unittest.cc

Index: test/unittests/compiler/js-intrinsic-lowering-unittest.cc
diff --git a/test/unittests/compiler/js-intrinsic-lowering-unittest.cc b/test/unittests/compiler/js-intrinsic-lowering-unittest.cc
index 1b8a87e8b2c83055a5a1bab9d97f42f0b637b73e..1e9954cbebf49851a2c35a91b4fa1fb4dcca32df 100644
--- a/test/unittests/compiler/js-intrinsic-lowering-unittest.cc
+++ b/test/unittests/compiler/js-intrinsic-lowering-unittest.cc
@@ -224,6 +224,23 @@ TEST_F(JSIntrinsicLoweringTest, InlineIsRegExp) {
 
 
 // -----------------------------------------------------------------------------
+// %_MathClz32
+
+
+TEST_F(JSIntrinsicLoweringTest, InlineMathClz32) {
+  Node* const input = Parameter(0);
+  Node* const context = Parameter(1);
+  Node* const effect = graph()->start();
+  Node* const control = graph()->start();
+  Reduction const r = Reduce(
+      graph()->NewNode(javascript()->CallRuntime(Runtime::kInlineMathClz32, 1),
+                       input, context, effect, control));
+  ASSERT_TRUE(r.Changed());
+  EXPECT_THAT(r.replacement(), IsWord32Clz(input));
+}
+
+
+// -----------------------------------------------------------------------------
 // %_ValueOf