public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/106458] [12/13 Regression] glibc's malloc/tst-scratch_buffer.c test is miscompiled with gcc-12
Date: Wed, 10 Aug 2022 13:30:24 +0000	[thread overview]
Message-ID: <bug-106458-4-EswGTqSM2H@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-106458-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106458

--- Comment #11 from Richard Biener <rguenth at gcc dot gnu.org> ---
The dump difference is easily explained by taming PRE when -ftree-vectorize is
on, it's not a "real" difference.

When I try with a cc1 cross I see

> ./cc1 -quiet t.i -fpreprocessed -O2 -g -std=gnu11 -fgnu89-inline -fmerge-all-constants -frounding-math -fno-stack-protector -fno-common -fmath-errno    -fno-pie -fopt-info-vec

and nothing actually vectorized.  Besides the PRE there seems to be a missed
DSE at the end (when vectorization is enabled as after the change):

   # DEBUG BEGIN_STMT
   memset (&buf.__space.__c, 64, 1024);
   # DEBUG BEGIN_STMT
+  sizes[0] = 16;
   sizes[1] = 1024;
   sizes[2] = 1040;

otherwise I see nothing suspicious in differences in .optimized when
comparing -fdump-tree-optimized with/without -fno-tree-vectorize.

You could try if -fno-tree-pre reproduces it also before the change.

  parent reply	other threads:[~2022-08-10 13:30 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-27 19:40 [Bug target/106458] New: [12 " danglin at gcc dot gnu.org
2022-07-27 19:41 ` [Bug target/106458] " danglin at gcc dot gnu.org
2022-07-27 19:42 ` danglin at gcc dot gnu.org
2022-07-27 19:42 ` danglin at gcc dot gnu.org
2022-07-28  8:12 ` [Bug target/106458] [12/13 " rguenth at gcc dot gnu.org
2022-07-29 12:50 ` dave.anglin at bell dot net
2022-07-29 14:46 ` dave.anglin at bell dot net
2022-07-30  7:09 ` sam at gentoo dot org
2022-08-04 14:14 ` [Bug tree-optimization/106458] " danglin at gcc dot gnu.org
2022-08-07 22:22 ` danglin at gcc dot gnu.org
2022-08-07 22:23 ` danglin at gcc dot gnu.org
2022-08-10 13:30 ` rguenth at gcc dot gnu.org [this message]
2022-08-10 14:53 ` dave.anglin at bell dot net
2022-08-10 17:38 ` dave.anglin at bell dot net
2022-08-10 18:12 ` dave.anglin at bell dot net
2022-08-10 20:53 ` dave.anglin at bell dot net
2022-11-05 20:54 ` danglin at gcc dot gnu.org
2022-11-06  6:39 ` pinskia at gcc dot gnu.org

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=bug-106458-4-EswGTqSM2H@http.gcc.gnu.org/bugzilla/ \
    --to=gcc-bugzilla@gcc.gnu.org \
    --cc=gcc-bugs@gcc.gnu.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).