[Bug c++/78773] "Empty" const only class not optimized away

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78773

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Actually constexpr won't work here as you have a cast from an integer to a
pointer ...