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From: "yuri at tsoft dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/25500] REGREGRESSION: SSE2 vectorized code is many times slower on 4.x.x than on 3.4.4
Date: Tue, 20 Dec 2005 07:40:00 -0000 [thread overview]
Message-ID: <20051220074050.9401.qmail@sourceware.org> (raw)
In-Reply-To: <bug-25500-6649@http.gcc.gnu.org/bugzilla/>
------- Comment #11 from yuri at tsoft dot com 2005-12-20 07:40 -------
Subject: Re: REGREGRESSION: SSE2 vectorized code is many
times slower on 4.x.x than on 3.4.4
Now this huge runtime difference disappeared
but now 4.0.2-generated code is always ~> 20% slower.
Many memory accesses where they are not needed at all and did not exist
for 3.4.4.
I tried -march=i686 and -march=k8, both are slower than 3.4.4.
Do I also have to recompile gcc with some special options?
Yuri
pinskia at gcc dot gnu dot org wrote:
>------- Comment #10 from pinskia at gcc dot gnu dot org 2005-12-20 06:55 -------
>Oh, I looked a little more and yes it depends on the arch you are building for
>but only for 4.x.
>
>Since you are using SSE, you should add also -march=i686 or -march=k8 so that
>the code is also tuned for the processor you are using.
>
>Anyways the problem with i386 with 4.0 is really just PR 14295.
>
>
>
>
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25500
next prev parent reply other threads:[~2005-12-20 7:40 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-12-20 5:25 [Bug c/25500] New: " yuri at tsoft dot com
2005-12-20 5:34 ` [Bug c/25500] " yuri at tsoft dot com
2005-12-20 5:55 ` [Bug target/25500] " pinskia at gcc dot gnu dot org
2005-12-20 6:01 ` yuri at tsoft dot com
2005-12-20 6:03 ` yuri at tsoft dot com
2005-12-20 6:19 ` yuri at tsoft dot com
2005-12-20 6:33 ` pinskia at gcc dot gnu dot org
2005-12-20 6:36 ` pinskia at gcc dot gnu dot org
2005-12-20 6:51 ` yuri at tsoft dot com
2005-12-20 6:55 ` pinskia at gcc dot gnu dot org
2005-12-20 7:40 ` yuri at tsoft dot com [this message]
2005-12-25 1:02 ` [Bug target/25500] [4.0/4.1/4.2 Regression]: " pinskia at gcc dot gnu dot org
2005-12-28 16:53 ` jakub at gcc dot gnu dot org
2006-01-15 22:13 ` [Bug target/25500] [4.0/4.1/4.2 Regression]: SSE2 vectorized code is " mmitchel at gcc dot gnu dot org
2006-02-24 0:31 ` mmitchel at gcc dot gnu dot org
2006-05-25 2:38 ` [Bug target/25500] [4.0/4.1/4.2 Regression]: SSE2 vectorized code is slower on 4.x.x than previous mmitchel at gcc dot gnu dot org
2006-07-05 9:50 ` pinskia at gcc dot gnu dot org
2006-08-07 7:55 ` bonzini at gnu dot org
2006-08-07 7:59 ` bonzini at gnu dot org
2006-08-07 15:36 ` pinskia at gcc dot gnu dot org
2006-08-17 8:16 ` bonzini at gnu dot org
2006-08-18 16:16 ` bonzini at gnu dot org
2006-11-12 8:07 ` [Bug target/25500] [4.0/4.1/4.2/4.3 " pinskia at gcc dot gnu dot org
2006-11-15 0:38 ` pinskia at gcc dot gnu dot org
2006-11-20 20:29 ` pinskia at gcc dot gnu dot org
2006-11-20 20:29 ` pinskia at gcc dot gnu dot org
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