public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "amker at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/98736] [10/11 Regression] Wrong partition order generated in loop distribution pass since r10-619-g5879ab5fafedc8f6
Date: Sun, 21 Mar 2021 04:41:04 +0000	[thread overview]
Message-ID: <bug-98736-4-fSxdYAwNaX@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-98736-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98736

--- Comment #4 from bin cheng <amker at gcc dot gnu.org> ---
(In reply to bin cheng from comment #3)
> hmm, seems topological order isn't enough for distributing a loop nest, we
> need topological order plus inner loop depth-first.

Well, not really.  In this case, problem is that rev-post order algorithm puts
"a[c] = d[3];" before the inner loop which violates the original program order. 

Seems that it can be fixed by inner loop depth-first order wrto how we
distribute inner loop, but I am not sure if this always preserves programming
order because loop has been reformed by various optimizers.

  parent reply	other threads:[~2021-03-21  4:41 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-18 19:40 [Bug tree-optimization/98736] New: Wrong partition order generated in loop distribution pass krebbel at gcc dot gnu.org
2021-01-18 19:41 ` [Bug tree-optimization/98736] " krebbel at gcc dot gnu.org
2021-01-19  7:52 ` [Bug tree-optimization/98736] [10/11 Regression] " rguenth at gcc dot gnu.org
2021-01-19  9:30 ` [Bug tree-optimization/98736] [10/11 Regression] Wrong partition order generated in loop distribution pass since r10-619-g5879ab5fafedc8f6 marxin at gcc dot gnu.org
2021-02-17 15:07 ` amker at gcc dot gnu.org
2021-03-21  4:41 ` amker at gcc dot gnu.org [this message]
2021-04-07  2:29 ` cvs-commit at gcc dot gnu.org
2021-04-07  2:32 ` amker at gcc dot gnu.org
2021-04-07  7:19 ` rguenth at gcc dot gnu.org
2021-04-07  7:21 ` [Bug tree-optimization/98736] [10 " rguenth at gcc dot gnu.org
2021-04-08 12:02 ` rguenth at gcc dot gnu.org
2021-04-23 13:00 ` cvs-commit at gcc dot gnu.org
2021-04-23 13:01 ` rguenth 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-98736-4-fSxdYAwNaX@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).