[Bug c++/78522] -O2 optimization confused by enum and pointer usage in constructors.

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78522

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|WONTFIX                     |INVALID

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Samuel T C Huang from comment #0)
>     helper.run(reinterpret_cast<uint32_t*>(&value_type));

The problem is here. This cast leads to an aliasing violation when you assign
through the pointer, so the program has undefined behaviour.

Don't do that.