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From: "hjl dot tools at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/38306] [4.4 Regression] 15% slowdown w.r.t. 4.3 of computational kernel on some architectures
Date: Wed, 03 Dec 2008 21:29:00 -0000 [thread overview]
Message-ID: <20081203212814.26899.qmail@sourceware.org> (raw)
In-Reply-To: <bug-38306-6642@http.gcc.gnu.org/bugzilla/>
------- Comment #8 from hjl dot tools at gmail dot com 2008-12-03 21:28 -------
(In reply to comment #5)
> (In reply to comment #4)
> > 4.3:
> > -O3 -march=native -funroll-loops -ffast-math ==> 4.376
> > -O3 -march=native -funroll-loops -ffast-math -fschedule-insns ==> 3.372
>
> strangely:
>
> http://gcc.gnu.org/onlinedocs/gcc-4.3.2/gcc/Optimize-Options.html#Optimize-Options
> suggests -fschedule-insns is enabled by default at -O3 ?
>
This may be related to PR 37565. i386.c has
void
optimization_options (int level, int size ATTRIBUTE_UNUSED)
{
/* For -O2 and beyond, turn off -fschedule-insns by default. It tends to
make the problem with not enough registers even worse. */
#ifdef INSN_SCHEDULING
if (level > 1)
flag_schedule_insns = 0;
#endif
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38306
next prev parent reply other threads:[~2008-12-03 21:29 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-28 16:02 [Bug target/38306] New: [4.4 Regression] 15% slowdown of computational kernel jv244 at cam dot ac dot uk
2008-11-28 16:03 ` [Bug target/38306] " jv244 at cam dot ac dot uk
2008-11-28 16:25 ` pinskia at gcc dot gnu dot org
2008-11-30 11:40 ` rguenth at gcc dot gnu dot org
2008-11-30 11:49 ` rguenth at gcc dot gnu dot org
2008-11-30 16:18 ` jv244 at cam dot ac dot uk
2008-11-30 16:27 ` jv244 at cam dot ac dot uk
2008-11-30 16:40 ` rguenth at gcc dot gnu dot org
2008-12-03 19:04 ` [Bug target/38306] [4.4 Regression] 15% slowdown w.r.t. 4.3 of computational kernel on some architectures steven at gcc dot gnu dot org
2008-12-03 21:29 ` hjl dot tools at gmail dot com [this message]
2008-12-04 16:12 ` jv244 at cam dot ac dot uk
2008-12-05 12:18 ` rguenth at gcc dot gnu dot org
2008-12-06 15:38 ` steven at gcc dot gnu dot org
2008-12-06 18:56 ` jv244 at cam dot ac dot uk
2009-02-11 19:00 ` bonzini at gnu dot org
2009-02-11 19:25 ` jv244 at cam dot ac dot uk
2009-04-21 15:59 ` [Bug target/38306] [4.4/4.5 " jakub at gcc dot gnu dot org
2009-07-22 10:35 ` jakub at gcc dot gnu dot org
2009-09-01 6:56 ` jv244 at cam dot ac dot uk
2009-09-01 8:54 ` bonzini at gnu dot org
2009-09-01 9:13 ` jv244 at cam dot ac dot uk
2009-09-01 9:18 ` jv244 at cam dot ac dot uk
2009-10-15 12:50 ` jakub at gcc dot gnu dot org
2010-01-21 13:19 ` jakub at gcc dot gnu dot org
2010-04-30 9:00 ` [Bug target/38306] [4.4/4.5/4.6 " jakub at gcc dot gnu dot org
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