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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Jakub Jelinek <jakub@redhat.com>
Cc: Jim Bos <jim876@xs4all.nl>, Andi Kleen <andi@firstfloor.org>,
	James Cloos <cloos@jhcloos.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Andreas Schwab <schwab@redhat.com>, Michael Matz <matz@suse.de>,
	Dave Korn <dave.korn.cygwin@gmail.com>,
	Richard Guenther <richard.guenther@gmail.com>,
	gcc@gcc.gnu.org
Subject: Re: gcc 4.5.1 / as 2.20.51.0.11 miscompiling drivers/char/i8k.c ?
Date: Mon, 15 Nov 2010 11:21:30 -0800	[thread overview]
Message-ID: <AANLkTikeYLrqXhvTP_uuKnKhy=k7pAQCbONJdKBc838O@mail.gmail.com> (raw)
In-Reply-To: <20101115191248.GY29412@tyan-ft48-01.lab.bos.redhat.com>

On Mon, Nov 15, 2010 at 11:12 AM, Jakub Jelinek <jakub@redhat.com> wrote:
>
> Ah, the problem is that memory_identifier_string is only initialized in
> ipa-reference.c's initialization, so it can be (and is in this case) NULL in
> ipa-pure-const.c.

Ok. And I guess you can verify that all versions of gcc do this
correctly for "asm volatile"?

Because since we'll have to work around this problem in the kernel, I
suspect the simplest solution is to remove the "+m" that causes
register pressure problems, and then use "asm volatile" to work around
the const-function bug.

And add a large comment about why "asm volatile" is probably always a
good idea when you have a memory clobber and don't have any other
visible memory modifications.

I do wonder if this explains some of the problems we had with the
bitop asms too.

Hmm?

                       Linus

  reply	other threads:[~2010-11-15 19:22 UTC|newest]

Thread overview: 129+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-11-06 11:15 gcc 4.5.1 / as 2.20.51.0.11 miscompiling drivers/char/i8k.c ? Jim
2010-11-07 21:31 ` Andi Kleen
2010-11-07 22:41   ` Andreas Schwab
2010-11-07 23:03     ` Andi Kleen
2010-11-08 10:49       ` Richard Guenther
2010-11-08 11:20         ` Andi Kleen
2010-11-08 11:20           ` Richard Guenther
2010-11-08 11:47             ` Paul Koning
2010-11-08 11:53               ` Jakub Jelinek
2010-11-08 12:20           ` Michael Matz
2010-11-08 18:39           ` Dave Korn
2010-11-09 13:00             ` Michael Matz
2010-11-09 13:48               ` Andi Kleen
2010-11-09 13:57                 ` Andreas Schwab
2010-11-09 16:43                   ` Jim
2010-11-13 11:13                     ` [PATCH] i8k: Tell gcc that *regs gets clobbered Jim Bos
2010-11-15  0:52                     ` gcc 4.5.1 / as 2.20.51.0.11 miscompiling drivers/char/i8k.c ? James Cloos
2010-11-15  3:21                       ` Linus Torvalds
2010-11-15  8:56                         ` Jakub Jelinek
2010-11-15  9:12                           ` Andi Kleen
2010-11-15  9:20                           ` Jakub Jelinek
2010-11-15 10:03                           ` Jakub Jelinek
2010-11-15 10:54                             ` Andi Kleen
2010-11-15 11:16                               ` Jakub Jelinek
2010-11-15 11:37                                 ` Andi Kleen
2010-11-15 17:36                                   ` Jim Bos
2010-11-15 17:44                                     ` Jakub Jelinek
2010-11-15 18:17                                       ` Jim Bos
2010-11-15 18:26                                         ` Jakub Jelinek
2010-11-15 19:10                                           ` Jim Bos
2010-11-15 16:04                                 ` Linus Torvalds
2010-11-15 17:40                                   ` Jim Bos
2010-11-15 18:08                                     ` Linus Torvalds
2010-11-15 18:30                                       ` Jim Bos
2010-11-15 18:37                                         ` Jim Bos
2010-11-15 18:56                                         ` Linus Torvalds
2010-11-15 18:58                                         ` Jakub Jelinek
2010-11-15 19:12                                           ` Jakub Jelinek
2010-11-15 19:21                                             ` Linus Torvalds [this message]
2010-11-15 19:51                                               ` Jakub Jelinek
2010-11-15 20:22                                                 ` Jim Bos
2011-06-03 13:05                                                   ` 2.6.39.1 immediately reboots/resets on EFI system Jim Bos
2011-06-03 13:33                                                     ` Matthew Garrett
2011-06-03 14:26                                                       ` Jim Bos
2011-06-03 14:46                                                         ` Matthew Garrett
2011-06-05 10:40                                                           ` Jim Bos
2011-06-05 12:57                                                             ` Maarten Lankhorst
2011-06-06 15:01                                                           ` Maarten Lankhorst
2011-06-06 15:40                                                             ` Jim Bos
2011-06-06 15:44                                                             ` Matthew Garrett
2011-06-06 15:27                                                         ` Maarten Lankhorst
2011-06-06 16:11                                                           ` Jim Bos
2011-06-06 16:43                                                             ` Maarten Lankhorst
2011-06-07  0:19                                                               ` Yinghai Lu
2011-06-07  1:41                                                                 ` Matthew Garrett
2011-06-07  2:05                                                                   ` Yinghai Lu
2011-06-07  8:25                                                                     ` Maarten Lankhorst
2011-06-07 15:14                                                                       ` Yinghai Lu
2011-06-07  9:08                                                                     ` Maarten Lankhorst
2011-06-07 12:22                                                                       ` Maarten Lankhorst
2011-06-07 22:25                                                                         ` Yinghai Lu
2011-06-08 16:44                                                                           ` Jim Bos
2011-06-08 19:17                                                                             ` Yinghai Lu
2011-06-08 19:23                                                                               ` Matthew Garrett
2011-06-08 19:27                                                                                 ` Yinghai Lu
2011-06-08 19:29                                                                                   ` Matthew Garrett
2011-06-08 19:35                                                                                     ` Yinghai Lu
2011-06-08 19:38                                                                                       ` Matthew Garrett
2011-06-08 19:46                                                                                         ` Yinghai Lu
2011-06-08 19:52                                                                                           ` Matthew Garrett
2011-06-08 19:48                                                                                         ` Yinghai Lu
2011-06-08 19:52                                                                                           ` Matthew Garrett
2011-06-08 20:03                                                                                             ` Yinghai Lu
2011-06-08 20:09                                                                                               ` Matthew Garrett
2011-06-08 20:23                                                                                                 ` Yinghai Lu
2011-06-08 20:30                                                                                                   ` Matthew Garrett
2011-06-08 20:36                                                                                                     ` Yinghai Lu
2011-06-08 20:42                                                                                                       ` Matthew Garrett
2011-06-08 20:46                                                                                                         ` Yinghai Lu
2011-06-08 21:06                                                                                                           ` Matthew Garrett
2011-06-08 21:06                                                                                                         ` Linus Torvalds
2011-06-08 21:28                                                                                                           ` Matthew Garrett
2011-06-08 21:31                                                                                                             ` H. Peter Anvin
2011-06-08 21:36                                                                                                               ` Matthew Garrett
2011-06-08 21:31                                                                                                             ` Linus Torvalds
2011-06-08 21:42                                                                                                               ` Matthew Garrett
2011-06-08 21:51                                                                                                               ` H. Peter Anvin
2011-06-08 22:57                                                                                                                 ` Linus Torvalds
2011-06-08 23:54                                                                                                                   ` Maarten Lankhorst
2011-06-08 21:38                                                                                                             ` Yinghai Lu
2011-06-10 16:47                                                                       ` Matthew Garrett
2011-06-10 17:51                                                                         ` Maarten Lankhorst
2011-06-10 17:54                                                                           ` Matthew Garrett
2011-06-10 22:45                                                                             ` Maarten Lankhorst
2011-06-10 22:58                                                                               ` Yinghai Lu
2011-06-10 23:03                                                                                 ` Matthew Garrett
2011-06-10 23:17                                                                                   ` Greg KH
2011-06-10 23:22                                                                                     ` Maarten Lankhorst
2011-06-10 23:25                                                                                     ` H. Peter Anvin
2011-06-10 23:26                                                                                   ` Yinghai Lu
2011-06-10 23:32                                                                                     ` H. Peter Anvin
2011-06-10 23:55                                                                                       ` Yinghai Lu
2011-06-11  0:00                                                                                         ` H. Peter Anvin
2011-06-11  0:19                                                                                           ` Yinghai Lu
2011-06-14 18:06                                                                                             ` H. Peter Anvin
2011-06-11 15:29                                                                                     ` Matthew Garrett
2011-06-10 23:00                                                                               ` Yinghai Lu
2011-06-13 16:47                                                                               ` Matthew Garrett
2011-06-13 17:52                                                                                 ` Maarten Lankhorst
2011-06-13 18:00                                                                                   ` Matthew Garrett
2011-06-13 18:14                                                                                     ` Maarten Lankhorst
2011-06-13 18:17                                                                                       ` Matthew Garrett
2011-06-13 18:23                                                                                         ` Maarten Lankhorst
2011-06-13 18:33                                                                                           ` Matthew Garrett
2011-06-13 18:45                                                                                             ` Maarten Lankhorst
2011-06-14 14:34                                                                                             ` Maarten Lankhorst
2011-06-14 14:50                                                                                             ` Maarten Lankhorst
2011-06-14 14:55                                                                                               ` Matthew Garrett
2010-11-15 22:43                                                 ` gcc 4.5.1 / as 2.20.51.0.11 miscompiling drivers/char/i8k.c ? Andi Kleen
2010-11-15 22:46                                                   ` Jakub Jelinek
2010-11-15 19:53                                             ` Richard Henderson
2010-11-15 10:24                           ` Richard Guenther
2010-11-15 18:45         ` Jeff Law
2010-11-15 19:04           ` Linus Torvalds
2010-11-15 22:07           ` Richard Guenther
2010-11-15 22:58             ` Jeff Law
2010-11-15 23:07               ` Richard Guenther
2010-11-16  4:10                 ` Jeff Law
2010-11-15 18:42     ` Jeff Law

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