On Thu, Sep 16, 2021 at 03:39:46PM +0000, Qing Zhao wrote:
> > Even -mtune= is needed if you want to stay safe, otherwise people testing
> > with --target_board=unix/-mtune=cascadelake (or whatever else) might get
> > failures.
>
> Okay. Will try this.
> >
> >>> and ideally also -fno-stack-protector
> >>> -fno-stack-clash-protection etc.
> >>
> >> Could you explain a little bit on this why?
> >
> > In case people test e.g. with --target_board=unix/\{,-fstack-protector-all\}
> > etc. (e.g. in Fedora/RHEL we do).
> > For the RTL scanning checks if they are done fairly early, those options
> > might not change anything, but with the ones scanning in the assembly,
> > one needs to watch if those options don't add e.g. in the prologue or
> > epilogue further copies of the instructions you scan for.
>
> I see.
>
> Thank you.
Basically, try to test with a bunch of semi-randomly chosen option sets and
see what breaks and what works and then for the cases you think are common
enough and worth adjusting testcases adjust them, otherwise add dg-options
to make sure the expected arch/tune/etc. are in effect.
make check-gcc
RUNTESTFLAGS='--target_board=unix\{-m64,-m64/-march=skylake-avx512,-m64/-fstack-protector-all,-m64/-fstack-clash-protection,-m32/-mno-sse,-m32/-mtune=bonnell,-m32/-march=bonnell,-m32/-fstack-protector-all/-fstack-clash-protection\}
i386.exp=auto-init*'
etc.
Jakub
