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From: "rguenther at suse dot de" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/108410] x264 averaging loop not optimized well for avx512
Date: Mon, 12 Jun 2023 08:06:37 +0000	[thread overview]
Message-ID: <bug-108410-4-ajTp5zPsuU@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-108410-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108410

--- Comment #7 from rguenther at suse dot de <rguenther at suse dot de> ---
On Mon, 12 Jun 2023, crazylht at gmail dot com wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108410
> 
> --- Comment #6 from Hongtao.liu <crazylht at gmail dot com> ---
> 
> > and the key thing to optimize is
> > 
> >   ivtmp_78 = ivtmp_77 + 4294967232; // -64
> >   _79 = MIN_EXPR <ivtmp_78, 255>;
> >   _80 = (unsigned char) _79;
> >   _81 = {_80, _80, _80, _80, _80, _80, _80, _80, _80, _80, _80, _80, _80,
> > _80, _80, _80, _80, _80, _80, _80, _80, _80, _80, _80, _80, _80, _80, _80,
> > _80, _80, _80, _80, _80, _80, _80, _80, _80, _80, _80, _80, _80, _80, _80,
> > _80, _80, _80, _80, _80, _80, _80, _80, _80, _80, _80, _80, _80, _80, _80,
> > _80, _80, _80, _80, _80, _80};
> > 
> > that is we want to broadcast a saturated (to vector element precision) value.
> 
> Yes, backend needs to support vec_pack_ssat_m, vec_pack_usat_m.

Can x86 do this?  We'd want to apply this to a scalar, so move ivtmp
to xmm, apply pack_usat or as you say below, the non-existing us_trunc
and then broadcast.

  parent reply	other threads:[~2023-06-12  8:06 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-14 20:55 [Bug middle-end/108410] New: " hubicka at gcc dot gnu.org
2023-01-16  8:07 ` [Bug middle-end/108410] " rguenth at gcc dot gnu.org
2023-01-18 12:33 ` rguenth at gcc dot gnu.org
2023-01-18 12:46 ` rguenth at gcc dot gnu.org
2023-06-07 12:22 ` rguenth at gcc dot gnu.org
2023-06-09 12:11 ` rguenth at gcc dot gnu.org
2023-06-12  5:48 ` crazylht at gmail dot com
2023-06-12  8:06 ` rguenther at suse dot de [this message]
2023-06-13  3:45 ` crazylht at gmail dot com
2023-06-13  8:05 ` rguenther at suse dot de
2023-06-14 12:54 ` rguenth at gcc dot gnu.org
2024-02-09 13:53 ` rguenth at gcc dot gnu.org
2024-04-15 13:29 ` rguenth at gcc dot gnu.org

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