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

src/compiler/x64/code-generator-x64.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/scopes.h"
@@ skipping 676 matching lines @@
       break;
     case kX64Sar:
       ASSEMBLE_SHIFT(sarq, 6);
       break;
     case kX64Ror32:
       ASSEMBLE_SHIFT(rorl, 5);
       break;
     case kX64Ror:
       ASSEMBLE_SHIFT(rorq, 6);
       break;
+    case kX64Lzcnt32:
+      if (instr->InputAt(0)->IsRegister()) {
+        __ Lzcntl(i.OutputRegister(), i.InputRegister(0));
+      } else {
+        __ Lzcntl(i.OutputRegister(), i.InputOperand(0));
+      }
+      break;
     case kSSEFloat64Cmp:
       ASSEMBLE_DOUBLE_BINOP(ucomisd);
       break;
     case kSSEFloat64Add:
       ASSEMBLE_DOUBLE_BINOP(addsd);
       break;
     case kSSEFloat64Sub:
       ASSEMBLE_DOUBLE_BINOP(subsd);
       break;
     case kSSEFloat64Mul:
@@ skipping 786 matching lines @@
     }
   }
   MarkLazyDeoptSite();
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace compiler
 }  // namespace v8