public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "uros at kss-loka dot si" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/21676] [4.0/4.1/4.2 Regression] Optimizer regression: SciMark sparse matrix benchmark
Date: Thu, 17 Aug 2006 07:21:00 -0000	[thread overview]
Message-ID: <20060817072124.22893.qmail@sourceware.org> (raw)
In-Reply-To: <bug-21676-10607@http.gcc.gnu.org/bugzilla/>



------- Comment #7 from uros at kss-loka dot si  2006-08-17 07:21 -------
(In reply to comment #6)

> I think that remaining time difference is due to strange loop above innermost:

... due to strange _header_ above innermost loop ...

The problem is that we load zero in both arms of "if".

This is what I get in .099t.optimized (using gcc-4.2 -O2 -fno-ivopts):

<L1>:;
  r.0 = (unsigned int) r;
  D.1556 = r.0 * 4;
  rowR = *((int *) D.1556 + row);
  rowRp1 = *((int *) D.1556 + row + 4B);
  if (rowR < rowRp1) goto <L41>; else goto <L42>;

<L42>:;
  sum = 0.0;
  goto <bb 5> (<L4>);

<L41>:;
  i = rowR;
  sum = 0.0;

Assignment to sum should be moved before if...

SSE is able to somehow CSE zero load during RTL:

.L8:
        movl 20(%ebp), %edx
        movapd  %xmm2, %xmm1
        movl (%edx,%ebx,4), %eax
        movl 4(%edx,%ebx,4), %ecx
        cmpl %ecx, %eax
        jge .L11
        movl %eax, %edx
        .p2align 4,,7
.L12:


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21676


  parent reply	other threads:[~2006-08-17  7:21 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <bug-21676-10607@http.gcc.gnu.org/bugzilla/>
2006-06-04 19:59 ` jsm28 at gcc dot gnu dot org
2006-06-04 20:06 ` pinskia at gcc dot gnu dot org
2006-06-06 11:46 ` gcc at pdoerfler dot com
2006-07-10 12:45 ` rguenth at gcc dot gnu dot org
2006-08-16  6:50 ` pinskia at gcc dot gnu dot org
2006-08-16 12:16 ` uros at kss-loka dot si
2006-08-17  7:21 ` uros at kss-loka dot si [this message]
2006-08-17  7:46 ` uros at kss-loka dot si
2006-08-29  5:24 ` [Bug rtl-optimization/21676] [4.0/4.1 " pinskia at gcc dot gnu dot org
2006-08-29  6:13 ` [Bug rtl-optimization/21676] [4.0/4.1/4.2 " uros at kss-loka dot si
2007-02-14  9:11 ` [Bug rtl-optimization/21676] [4.0/4.1/4.2/4.3 " mmitchel at gcc dot gnu dot org
2007-12-16 23:17 ` steven at gcc dot gnu dot org
2007-12-16 23:49 ` ubizjak at gmail dot com
2008-01-12 15:29 ` steven at gcc dot gnu dot org
2008-02-06 11:06 ` ubizjak at gmail dot com
2008-07-04 16:54 ` [Bug rtl-optimization/21676] [4.2/4.3/4.4 " jsm28 at gcc dot gnu dot org
2008-11-22 10:33 ` steven at gcc dot gnu dot org
2009-02-05  8:03 ` [Bug tree-optimization/21676] " bonzini at gnu dot org
2009-02-16  9:04 ` [Bug tree-optimization/21676] [4.2/4.3 " bonzini at gnu dot org
2009-03-31 18:47 ` [Bug tree-optimization/21676] [4.3 " jsm28 at gcc dot gnu dot org
2009-04-22 15:10 ` rguenth at gcc dot gnu dot 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=20060817072124.22893.qmail@sourceware.org \
    --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).