[Bug c++/81928] if(!this) optimization leads to possible errors without warnings

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81928

--- Comment #14 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Matthieu Brucher from comment #11)
> Oh, and if this is always false, why isn't it the case in debug mode? It is
> then a bug according to what you said.

It is always false in a valid program. If you create a situation where the this
pointer is null that's a bug in your program, not in GCC.