[Bug c/108340] compiler segfault

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108340

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
The trunk change caused various regressions and needed multiple follow-ups, I'm
afraid it is not a good idea to backport that.
r13-2658, r13-2709, r13-2891 at least.
Perhaps backporting the 2 match.pd hunks from r13-2658 and nothing else could
work for 12.3, provided it fixes the testcases.