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

src/compiler/ia32/code-generator-ia32.cc

 // Copyright 2013 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.
 
 #include "src/compiler/code-generator.h"
 
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
 #include "src/compiler/node-matchers.h"
 #include "src/ia32/assembler-ia32.h"
@@ skipping 429 matching lines @@
         __ sar_cl(i.OutputOperand());
       }
       break;
     case kIA32Ror:
       if (HasImmediateInput(instr, 1)) {
         __ ror(i.OutputOperand(), i.InputInt5(1));
       } else {
         __ ror_cl(i.OutputOperand());
       }
       break;
+    case kIA32Lzcnt:
+      __ Lzcnt(i.OutputRegister(), i.InputOperand(0));
+      break;
     case kSSEFloat64Cmp:
       __ ucomisd(i.InputDoubleRegister(0), i.InputOperand(1));
       break;
     case kSSEFloat64Add:
       __ addsd(i.InputDoubleRegister(0), i.InputOperand(1));
       break;
     case kSSEFloat64Sub:
       __ subsd(i.InputDoubleRegister(0), i.InputOperand(1));
       break;
     case kSSEFloat64Mul:
@@ skipping 867 matching lines @@
     }
   }
   MarkLazyDeoptSite();
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8