[Bug middle-end/112572] [14 regression] LLVM miscompiled since r14-5355-g3cd3a09b3f91a1

[sjames at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112572

--- Comment #27 from Sam James <sjames at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #18)
> This fixes the issue for me:
> ```
> diff --git a/gcc/compare-elim.cc b/gcc/compare-elim.cc
> [...]

This solves both pipewire (unreported, was working on reducing it; found it
needed -fstack-protector-strong and I think PIE) and LLVM failures. Thank you
Andrew & thanks Sergei for looking at it too.

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112613#c3 is an interesting
comment wrt checking. Is that feasible?

It would be nice if this was catchable with --enable-checking=rtl or
--enable-checking=df (I don't test with this regularly, but it would've been
helpful after seeing the bisect result), especially given there's some clear
(possible) misuse.