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From: "linkw at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/115355] [12/13/14/15 Regression] vectorization exposes wrong code on P9 LE starting from r12-4496
Date: Fri, 07 Jun 2024 08:14:53 +0000	[thread overview]
Message-ID: <bug-115355-4-e9z0ahYy82@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-115355-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115355

--- Comment #11 from Kewen Lin <linkw at gcc dot gnu.org> ---
(In reply to Jens Seifert from comment #10)
> Does this affect loop vectorize and slp vectorize ?
> 
> -fno-tree-loop-vectorize avoids loop vectorization to be performed and
> workarounds this issue. Does the same problems also affect SLP
> vectorization, which does not take place in this sample.
> 
> In other words, do I need
> -fno-tree-loop-vectorize
> or
> -fno-tree-vectorize
> to workaround this bug ?

Since it's an issue on vector merge insn patterns in target code and
vectorization just exposes it, it's hard to workaround this bug completely just
by disabling both loop and slp vectorization, as its related bug PR106069
shows, even without vectorization but using some vec merge built-ins, it's
still possible to hit this issue.  But I'd expect disabling both loop and slp
vectorization (-fno-tree-vectorize) can greatly reduce the possibility of
encountering it.

  parent reply	other threads:[~2024-06-07  8:14 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-06-05 10:39 [Bug target/115355] New: PPCLE: Auto-vectorization creates wrong code for Power9 jens.seifert at de dot ibm.com
2024-06-05 11:55 ` [Bug target/115355] " jens.seifert at de dot ibm.com
2024-06-05 12:30 ` rguenth at gcc dot gnu.org
2024-06-05 13:03 ` bergner at gcc dot gnu.org
2024-06-05 13:43 ` linkw at gcc dot gnu.org
2024-06-05 14:59 ` bergner at gcc dot gnu.org
2024-06-05 15:42 ` [Bug target/115355] [12/13/14/15 Regression] " pinskia at gcc dot gnu.org
2024-06-05 21:05 ` bergner at gcc dot gnu.org
2024-06-05 21:05 ` bergner at gcc dot gnu.org
2024-06-06  4:36 ` [Bug target/115355] [12/13/14/15 Regression] vectorization exposes wrong code on P9 LE starting from r12-4496 linkw at gcc dot gnu.org
2024-06-06  6:30 ` rguenth at gcc dot gnu.org
2024-06-06  6:35 ` linkw at gcc dot gnu.org
2024-06-07  6:53 ` jens.seifert at de dot ibm.com
2024-06-07  8:14 ` linkw at gcc dot gnu.org [this message]
2024-06-20  9:15 ` rguenth at gcc dot gnu.org
2024-06-21  1:27 ` cvs-commit at gcc dot gnu.org
2024-06-26  7:17 ` cvs-commit at gcc dot gnu.org
2024-06-26  7:17 ` cvs-commit at gcc dot gnu.org
2024-06-28  1:13 ` cvs-commit at gcc dot gnu.org
2024-06-28  1:14 ` cvs-commit at gcc dot gnu.org
2024-06-28  1:17 ` cvs-commit at gcc dot gnu.org

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