[Bug tree-optimization/78394] False positives of maybe-uninitialized with -Og

[egallager at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78394

--- Comment #15 from Eric Gallager <egallager at gcc dot gnu.org> ---
(In reply to Marc Glisse from comment #14)
> (In reply to Jeffrey A. Law from comment #12)
> > Whether or not to fix as well as whether or not to warn at -O0 are a topic
> > of debate.  I'm not sure I'm up for re-opening that can of worms right now.
> 
> I think we can both work on reducing false positives and move it out of
> -Wall, it isn't exclusive.
> 
> > I strongly believe -Wmaybe-uninitialized should continue to be enabled by
> > -Wall.   They tend to either point out obscure ways objects are
> > uninitialized or they point out missed optimizations.  Both are critical in
> > my mind.
> 
> -Wall
>            This enables all the warnings about constructions that some users
>            consider questionable, and that are easy to avoid (or modify to
>            prevent the warning), even in conjunction with macros.
> 
> I don't see how you can ever satisfy the "easy to avoid" part. In my
> experience with several code bases, having this warning in -Wall (as opposed
> to -Wextra) does more harm than good, with people doing random bad code
> changes to try and get the compiler to shut up.
> 
> I still believe this warning is a very useful static analysis tool (I
> contributed to make it appear more often in the past), but by definition it
> will never avoid false positives.

For reference, this conversation moved to gcc-patches here: 
https://gcc.gnu.org/ml/gcc-patches/2019-02/msg00020.html