456     }

   457     break;

   458   }

   459   case vmIntrinsics::_isInstance          : {

   460     assert(x->number_of_arguments() == 2, "wrong type");

   461 

   462     InstanceConstant* c = x->argument_at(0)->type()->as_InstanceConstant();

   463     if (c != NULL && !c->value()->is_null_object()) {

   464       // ciInstance::java_mirror_type() returns non-NULL only for Java mirrors

   465       ciType* t = c->value()->as_instance()->java_mirror_type();

   466       if (t->is_klass()) {

   467         // substitute cls.isInstance(obj) of a constant Class into

   468         // an InstantOf instruction

   469         InstanceOf* i = new InstanceOf(t->as_klass(), x->argument_at(1), x->state());

   470         set_canonical(i);

   471         // and try to canonicalize even further

   472         do_InstanceOf(i);

   473       } else {

   474         assert(t->is_primitive_type(), "should be a primitive type");

   475         // cls.isInstance(obj) always returns false for primitive classes

   476         set_constant(0);

   477       }