Hi Richi,
> -----Original Message-----
> From: rguent...@c653.arch.suse.de <rguent...@c653.arch.suse.de> On
> Behalf Of Richard Biener
> Sent: Thursday, October 22, 2020 9:44 AM
> To: Tamar Christina <tamar.christ...@arm.com>
> Cc: gcc-patches@gcc.gnu.org; nd <n...@arm.com>; o...@ucw.cz
> Subject: Re: [PATCH] SLP: Move load/store-lanes check till late
>
> On Wed, 21 Oct 2020, Tamar Christina wrote:
>
> > Hi All,
> >
> > This moves the code that checks for load/store lanes further in the
> > pipeline and places it after slp_optimize. This would allow us to
> > perform optimizations on the SLP tree and only bail out if we really have a
> permute.
> >
> > With this change it allows us to handle permutes such as {1,1,1,1}
> > which should be handled by a load and replicate.
> >
> > This change however makes it all or nothing. Either all instances can
> > be handled or none at all. This is why some of the test cases have been
> adjusted.
>
> So this possibly leaves a loop unvectorized in case there's a ldN/stN
> opportunity but another SLP instance with a permutation not handled by
> interleaving is present. What I was originally suggesting is to only cancel
> the
> SLP build if _all_ instances can be handled with ldN/stN.
Ah I had somehow misunderstood this. I'll make that change.
>
> Of course I'm also happy with completely removing this heuristics.
>
> Note some of the comments look off now, also the assignment to ok before
> the goto is pointless and you should probably turn this into a dump print
> instead.
Is it pointless? The first thing again does is assert:
again:
/* Ensure that "ok" is false (with an opt_problem if dumping is enabled). */
gcc_assert (!ok);
and up to that point ok would still be it's default value of
opt_result::success ();
So since I have to change it anyway I was using it to report the reason.
I can make it into a dump, but would still have to assign to `ok` unless I'm
missing
something.
Regards,
Tamar
>
> Thanks,
> Richard.
>
> > Bootstrapped Regtested on aarch64-none-linux-gnu, -x86_64-pc-linux-gnu
> > and no issues.
> >
> > Ok for master?
>
>
>
> > Thanks,
> > Tamar
> >
> > gcc/ChangeLog:
> >
> > * tree-vect-slp.c (vect_analyze_slp_instance): Moved load/store
> lanes
> > check to ...
> > * tree-vect-loop.c (vect_analyze_loop_2): ..Here
> >
> > gcc/testsuite/ChangeLog:
> >
> > * gcc.dg/vect/slp-11b.c: Update output scan.
> > * gcc.dg/vect/slp-perm-6.c: Likewise.
> >
> >
>
> --
> Richard Biener <rguent...@suse.de>
> SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409
> Nuernberg, Germany; GF: Felix Imend
