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

[crazylht at gmail dot com]

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

--- Comment #4 from Hongtao.liu <crazylht at gmail dot com> ---
(In reply to Martin Jambor from comment #3)
> (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.

What's your GCC option for OPENSUSE?

Default value of -mprefer-vector-width for -mtune=zenver1 is 128, if that, it
won't help.
Different processor have different tune which may has different default vector
width.