https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116133
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- The check in internal-fn.cc is: if (GET_MODE_2XWIDER_MODE (mode).exists (&wmode) && targetm.scalar_mode_supported_p (wmode) && can_widen_mult_without_libcall (wmode, mode, op0, op1, uns)) Oh can_widen_mult_without_libcall does test [us]mul_widen_optab first and then if that fails see if we could use the widen mul_opt. for the right now we should just test [us]mul_widen_optab .