[Bug libstdc++/105562] [12 Regression] std::function::_M_invoker may be used uninitialized in std::regex move with -fno-strict-aliasing

[rguenth at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105562

--- Comment #18 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Sven Hesse from comment #17)
> I still get this with gcc 12.2.0 (Gentoo 12.2.0 p9), but only when compiling
> with (at least with) -O1 -fsanitize=address, in addition to any warning flag
> that enables -Wmaybe-uninitialized (like -Wall, -Wextra or -Wuninitialized).
> 
> -O0 and/or no ASan, and the offending code compiles cleanly without any
> warnings. Somehow, the combination of enabling ASan and optimization
> (anything > -O0, but not -Os) triggers it again, it seems?
> 
> I can observe this with the testcase attached here in this bug report.

-fsanitize=address is likely to derail optimization enough to make such
occurences more likely, I think we have plenty of duplicate bugreports
for this.