[Bug c++/85091] Compiler generates different code depending on whether -Wnonnull -Woverloaded-virtual given or not

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85091

--- Comment #7 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to rguenther@suse.de from comment #5)
> It was whether the file was in a subdirectory or in the cwd, not
> whether the warnings were used.

Both:
https://gcc.gnu.org/ml/gcc-help/2018-03/msg00077.html