Optimize the typeof operator.

src/compiler/linkage.cc

 // Copyright 2014 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/code-stubs.h"
 #include "src/compiler.h"
 #include "src/compiler/linkage.h"
 #include "src/compiler/node.h"
 #include "src/compiler/pipeline.h"
 #include "src/scopes.h"
@@ skipping 112 matching lines @@
     case Runtime::kNewRestParamSlow:
     case Runtime::kPushBlockContext:
     case Runtime::kPushCatchContext:
     case Runtime::kReThrow:
     case Runtime::kSetProperty:  // TODO(jarin): Is it safe?
     case Runtime::kStringCompareRT:
     case Runtime::kStringEquals:
     case Runtime::kToFastProperties:  // TODO(jarin): Is it safe?
     case Runtime::kTraceEnter:
     case Runtime::kTraceExit:
-    case Runtime::kTypeof:
       return false;
     case Runtime::kInlineArguments:
     case Runtime::kInlineCallFunction:
     case Runtime::kInlineDateField:
     case Runtime::kInlineDeoptimizeNow:
     case Runtime::kInlineGetPrototype:
     case Runtime::kInlineRegExpExec:
       return true;
     default:
       break;
@@ skipping 56 matching lines @@
 
 CallDescriptor* Linkage::GetSimplifiedCDescriptor(Zone* zone,
                                                   const MachineSignature* sig) {
   UNIMPLEMENTED();
   return NULL;
 }
 #endif  // !V8_TURBOFAN_BACKEND
 }
 }
 }  // namespace v8::internal::compiler