Improve the generated code for the instanceof operator.

src/code-stubs.cc

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 92 matching lines @@
     case RecordWrite:
       return "RecordWrite";
     case StackCheck:
       return "StackCheck";
     case UnarySub:
       return "UnarySub";
     case RevertToNumber:
       return "RevertToNumber";
     case ToBoolean:
       return "ToBoolean";
+    case Instanceof:
+      return "Instanceof";
     case CounterOp:
       return "CounterOp";
     case ArgumentsAccess:
       return "ArgumentsAccess";
     case Runtime:
       return "Runtime";
     case CEntry:
       return "CEntry";
     case JSEntry:
       return "JSEntry";
     case GetProperty:
       return "GetProperty";
     case SetProperty:
       return "SetProperty";
     case InvokeBuiltin:
       return "InvokeBuiltin";
     case JSExit:
       return "JSExit";
     default:
       UNREACHABLE();
       return NULL;
   }
 }
 
 
 } }  // namespace v8::internal