[builtins] Migrate Math.clz32 to a TurboFan builtin.

src/compiler/code-stub-assembler.h

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_COMPILER_CODE_STUB_ASSEMBLER_H_
 #define V8_COMPILER_CODE_STUB_ASSEMBLER_H_
 
 #include <map>
 
 // Clients of this interface shouldn't depend on lots of compiler internals.
@@ skipping 85 matching lines @@
   V(Word64Sar)                                  \
   V(Word64Ror)
 
 #define CODE_STUB_ASSEMBLER_UNARY_OP_LIST(V) \
   V(Float64Neg)                              \
   V(Float64Sqrt)                             \
   V(ChangeFloat64ToUint32)                   \
   V(ChangeInt32ToFloat64)                    \
   V(ChangeInt32ToInt64)                      \
   V(ChangeUint32ToFloat64)                   \
-  V(ChangeUint32ToUint64)
+  V(ChangeUint32ToUint64)                    \
+  V(Word32Clz)
 
 class CodeStubAssembler {
  public:
   // Create with CallStub linkage.
   // |result_size| specifies the number of results returned by the stub.
   // TODO(rmcilroy): move result_size to the CallInterfaceDescriptor.
   CodeStubAssembler(Isolate* isolate, Zone* zone,
                     const CallInterfaceDescriptor& descriptor,
                     Code::Flags flags, const char* name,
                     size_t result_size = 1);
@@ skipping 348 matching lines @@
   // Map of variables to the list of value nodes that have been added from each
   // merge path in their order of merging.
   std::map<Variable::Impl*, std::vector<Node*>> variable_merges_;
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_CODE_STUB_ASSEMBLER_H_