From: Segher Boessenkool <segher@kernel.crashing.org>
To: Denis Vlasenko <vda.linux@googlemail.com>
Cc: akpm@osdl.org, Albert Cahalan <acahalan@gmail.com>,
linux-kernel@vger.kernel.org, s0348365@sms.ed.ac.uk,
Linus Torvalds <torvalds@osdl.org>,
bunk@stusta.de, mikpe@it.uu.se
Subject: Re: kernel + gcc 4.1 = several problems
Date: Sun, 7 Jan 2007 16:10:53 +0100 [thread overview]
Message-ID: <11fc5e81b224467e25caaefb66ba82e7@kernel.crashing.org> (raw)
In-Reply-To: <200701070525.45974.vda.linux@googlemail.com>
> I want this:
>
> char v[4];
> ...
> memcmp(v, "abcd", 4) == 0
>
> compile to single cmpl on i386. This (gcc 4.1.1) is ridiculous:
> call memcmp
i686-linux-gcc (GCC) 4.2.0 20060410 (experimental)
movl $4, %ecx #, tmp65
cld
movl $v, %esi #, tmp63
movl $.LC0, %edi #, tmp64
repz
cmpsb
sete %al #, tmp68
Still not perfect, but better already. If you have any
specific examples that you'd like to have compiled to
better code, please report them in GCC bugzilla (with a
self-contained testcase, please).
Segher
next prev parent reply other threads:[~2007-01-07 15:12 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-01-04 7:11 Albert Cahalan
2007-01-04 16:43 ` Segher Boessenkool
2007-01-04 17:04 ` Albert Cahalan
2007-01-04 17:24 ` Segher Boessenkool
2007-01-04 17:47 ` Linus Torvalds
2007-01-04 18:53 ` Segher Boessenkool
2007-01-04 19:10 ` Al Viro
2007-01-05 17:17 ` Pavel Machek
2007-01-06 8:23 ` Segher Boessenkool
2007-01-04 17:37 ` Linus Torvalds
2007-01-04 18:34 ` Segher Boessenkool
2007-01-04 22:02 ` Geert Bosch
2007-01-07 4:25 ` Denis Vlasenko
2007-01-07 4:45 ` Linus Torvalds
2007-01-07 5:26 ` Jeff Garzik
2007-01-07 15:10 ` Segher Boessenkool [this message]
2007-01-26 22:05 ` Michael K. Edwards
2007-01-04 18:08 ` Andreas Schwab
-- strict thread matches above, loose matches on Subject: below --
2007-01-03 2:12 Mikael Pettersson
2007-01-03 2:20 ` Alistair John Strachan
2007-01-05 15:53 ` Alistair John Strachan
2007-01-05 16:02 ` Linus Torvalds
2007-01-05 16:19 ` Alistair John Strachan
2007-01-05 16:49 ` Linus Torvalds
2007-01-07 0:36 ` Pavel Machek
2007-01-07 0:57 ` Alistair John Strachan
2007-01-03 5:55 ` Willy Tarreau
2007-01-03 10:29 ` Alan
2007-01-03 10:32 ` Grzegorz Kulewski
2007-01-03 11:51 ` Jeff Garzik
2007-01-03 12:44 ` Alan
2007-01-03 13:32 ` Arjan van de Ven
2007-01-03 13:58 ` Jakub Jelinek
2007-01-03 14:28 ` Alan
2007-01-03 16:06 ` Linus Torvalds
2007-01-03 16:03 ` Linus Torvalds
2007-01-03 17:01 ` l.genoni
2007-01-03 17:45 ` Tim Schmielau
2007-01-03 20:24 ` Linus Torvalds
2007-01-03 17:06 ` l.genoni
2007-01-03 17:53 ` Mariusz Kozlowski
2007-01-03 19:47 ` Denis Vlasenko
2007-01-03 20:38 ` Linus Torvalds
2007-01-03 21:48 ` Denis Vlasenko
2007-01-03 22:13 ` Linus Torvalds
2007-01-03 21:44 ` Thomas Sailer
2007-01-03 22:08 ` Linus Torvalds
2007-01-04 3:08 ` Zou, Nanhai
2007-01-04 15:34 ` Linus Torvalds
2006-12-20 14:21 Oops in 2.6.19.1 Alistair John Strachan
2006-12-30 16:59 ` Alistair John Strachan
2006-12-31 16:27 ` Adrian Bunk
2006-12-31 16:55 ` Alistair John Strachan
2007-01-02 21:10 ` kernel + gcc 4.1 = several problems Adrian Bunk
2007-01-02 21:56 ` Alistair John Strachan
2007-01-02 22:06 ` D. Hazelton
2007-01-02 23:24 ` Adrian Bunk
2007-01-02 23:41 ` D. Hazelton
2007-01-03 2:05 ` Horst H. von Brand
2007-01-02 22:13 ` Linus Torvalds
2007-01-02 23:18 ` Alistair John Strachan
2007-01-03 1:43 ` Linus Torvalds
2007-01-02 22:01 ` Linus Torvalds
2007-01-02 23:09 ` David Rientjes
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