[Bug tree-optimization/116133] Missing mult_overflow detection for aarch64

[pinskia at gcc dot gnu.org]

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 .