public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "ktkachov at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/67628] [tree-optimization] (a && b) && c shows better codegen than a && (b && c)
Date: Mon, 21 Sep 2015 14:23:00 -0000	[thread overview]
Message-ID: <bug-67628-4-xjl67UthJd@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-67628-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67628

--- Comment #4 from ktkachov at gcc dot gnu.org ---
(In reply to Andrew Pinski from comment #3)
> (In reply to ktkachov from comment #2)
> > (In reply to Andrew Pinski from comment #1)
> > > This is due to the fold-const.c optimization which should not be there any
> > > more. You need to do benchmarking on x86 also if you remove it. 
> > > 
> > 
> > could you elaborate what optimization is that?
> > Is it a matter of fold-const.c or match.pd canonicalizing the expression in
> > some way?
> 
> The optimization is converting andif into and. Basically ifcombine pass does
> not recombine them if fold-const does it early on.

Right, seems like the code in fold_truth_andor.
I think ifcombine should be doing a better job here though


  parent reply	other threads:[~2015-09-21 14:23 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-18 14:32 [Bug tree-optimization/67628] New: " ktkachov at gcc dot gnu.org
2015-09-18 14:48 ` [Bug tree-optimization/67628] " pinskia at gcc dot gnu.org
2015-09-18 15:00 ` ktkachov at gcc dot gnu.org
2015-09-18 15:10 ` pinskia at gcc dot gnu.org
2015-09-21 14:23 ` ktkachov at gcc dot gnu.org [this message]
2021-06-07  7:30 ` pinskia at gcc dot gnu.org
2021-07-20  6:50 ` pinskia at gcc dot gnu.org
2023-09-03  3:29 ` 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-67628-4-xjl67UthJd@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).