[Bug middle-end/122913] [16 Regression?] pr12392.cpp -Ofast compile time went up 66% when switching to -std=c++20

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122913

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
>I also noticed leela_r at `-O2 -flto` lost the small speedup which was gained 
>from my cleanupcfg patches too from moving to C++20 too:

That was fixed either by the ch improvement or
final_cleanupcfg/make_forwarders_with_degenerate_phis improvements.


So it is just the compile time problem left which did have a slight improvement
due to ch related patches.