[Bug middle-end/86284] Insert trap instruction in place of missing return statement on dodgy code

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86284

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
-fsanitize=unreachable will find the C++ cases right now.

For C, it is a little harder because it is only undefined if the value is used.