http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57390
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- There is no way to enable it for C++ because the extension has not been designed to how it would interact with templates and such. See the thread at http://gcc.gnu.org/ml/gcc/2011-11/msg00124.html for more info.
