[Bug target/84481] [8/9 Regression] 429.mcf with -O2 regresses by ~6% and ~4%, depending on tuning, on Zen compared to GCC 7.2

[jamborm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84481

--- Comment #8 from Martin Jambor <jamborm at gcc dot gnu.org> ---
And even my own measurements show 6% slowdown at both -O2 and -Ofast with
generic march/tuning against GCC 7 and now also 5% slowdown at -Ofast and
native march/tuning against GCC 8.