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From: "rguenth at gcc dot gnu.org" <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: Wed, 18 Jan 2023 12:46:40 +0000	[thread overview]
Message-ID: <bug-108410-4-QljmZRz3aB@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 #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
the naiive "bad" code-gen produces

size  512-masked
  2    12.19
  4     6.09
  6     4.06
  8     3.04
 12     2.03
 14     1.52
 16     1.21
 20     1.01
 24     0.87
 32     0.76
 34     0.71
 38     0.64
 42     0.58

on alberti (you seem to have used the same machine).  So the AVX512 "stupid"
code-gen is faster for 6+ elements and I guess optimizing it should then
outperform scalar also for 4 elements.  The exact matches for 8 on 128
and 16 on 256 are hard to beat of course, likewise the single or two iteration
case.

  parent reply	other threads:[~2023-01-18 12:46 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 [this message]
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
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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