[Bug c/126003] integer overflow during compile-time arithmetic is not always detected

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126003

Drea Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |INVALID

--- Comment #1 from Drea Pinski <pinskia at gcc dot gnu.org> ---
Use -fsanitize=undefined.

twogig+twogig is only undefined if executed.
While TWOGIG+TWOGIG is considered as part of a constant integer expression so
it need to warn there.