[Bug tree-optimization/94375] 548.exchange2_r run time is 8-18% worse than GCC 9 at -Ofast -march=native

[jamborm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94375

--- Comment #3 from Martin Jambor <jamborm at gcc dot gnu.org> ---
(In reply to Hongtao.liu from comment #1)
> Try -mprefer-vector-width=128,256-bit vectorization is not helpful for 548
> according to our experience.

I have seen this helping on one system running SLES 15.1 and with
trunk abe13e1847f (Feb 17 2020) but not on another running openSUSE
Tumbleweed and with trunk revision 26b3e568a60 (Mar 23 2020).  So,
from my perspective, perhaps it helps, perhaps it doesn't.