From: David Daney <ddaney@caviumnetworks•com>
To: Geert Uytterhoeven <geert@linux-m68k•org>
Cc: linux-mips@linux-mips•org,
Heiko Carstens <heiko.carstens@de•ibm.com>,
linuxppc-dev@ozlabs•org, Paul Mackerras <paulus@samba•org>,
"H. Peter Anvin" <hpa@zytor•com>,
linux-s390@vger•kernel.org, linux-am33-list@redhat•com,
Helge Deller <deller@gmx•de>,
x86@kernel•org, Ingo Molnar <mingo@redhat•com>,
Mike Frysinger <vapier@gentoo•org>,
Ivan Kokshaysky <ink@jurassic•park.msu.ru>,
linux390@de•ibm.com, Thomas Gleixner <tglx@linutronix•de>,
Richard Henderson <rth@twiddle•net>,
Haavard Skinnemoen <hskinnemoen@atmel•com>,
linux-parisc@vger•kernel.org, torvalds@linux-foundation•org,
linux-kernel@vger•kernel.org, ralf@linux-mips•org,
Kyle McMartin <kyle@mcmartin•ca>,
linux-alpha@vger•kernel.org,
Martin Schwidefsky <schwidefsky@de•ibm.com>,
uclinux-dist-devel@blackfin•uclinux.org,
akpm@linux-foundation•org,
Koichi Yasutake <yasutake.koichi@jp•panasonic.com>,
linuxppc-dev@lists•ozlabs.org
Subject: Re: [PATCH 01/10] Add support for GCC-4.5's __builtin_unreachable() to compiler.h
Date: Mon, 14 Sep 2009 08:40:23 -0700 [thread overview]
Message-ID: <4AAE63E7.90909@caviumnetworks.com> (raw)
In-Reply-To: <10f740e80909120022m72ad5ea7t692fba93cd3114e9@mail.gmail.com>
Geert Uytterhoeven wrote:
> On Fri, Sep 11, 2009 at 17:58, David Daney<ddaney@caviumnetworks•com> wrote:
>> Michael Buesch wrote:
>>> On Friday 11 September 2009 01:56:42 David Daney wrote:
>>>> +/* Unreachable code */
>>>> +#ifndef unreachable
>>>> +# define unreachable() do { for (;;) ; } while (0)
>>>> +#endif
>>> # define unreachable() do { } while (1)
>>>
>>> ? :)
>> Clearly I was not thinking clearly when I wrote that part. RTH noted the
>> same thing. I will fix it.
>
> However, people are so used to seeing the `do { } while (0)' idiom,
> that they might miss
> there's a `1' here, not a `0'.
>
> So perhaps it's better to use plain `for (;;)' for infinite loops?
>
I don't think so. The only valid token that can follow 'do { } while
(1)' is ';', any statement may follow 'for (;;)', so there is a greater
possibility to silently screw things up with the for(;;) form.
David Daney
next prev parent reply other threads:[~2009-09-14 15:40 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-10 23:54 [PATCH 00/10] Add support for GCC's __builtin_unreachable() and use it in BUG David Daney
2009-09-10 23:56 ` [PATCH 01/10] Add support for GCC-4.5's __builtin_unreachable() to compiler.h David Daney
2009-09-11 0:14 ` Richard Henderson
2009-09-11 14:32 ` Michael Buesch
2009-09-11 15:58 ` David Daney
2009-09-12 7:22 ` Geert Uytterhoeven
2009-09-14 15:40 ` David Daney [this message]
2009-09-10 23:56 ` [PATCH 07/10] powerpc: Convert BUG() to use unreachable() David Daney
2009-09-24 3:37 ` [PATCH 00/10] Add support for GCC's __builtin_unreachable() and use it in BUG Benjamin Herrenschmidt
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=4AAE63E7.90909@caviumnetworks.com \
--to=ddaney@caviumnetworks$(echo .)com \
--cc=akpm@linux-foundation$(echo .)org \
--cc=deller@gmx$(echo .)de \
--cc=geert@linux-m68k$(echo .)org \
--cc=heiko.carstens@de$(echo .)ibm.com \
--cc=hpa@zytor$(echo .)com \
--cc=hskinnemoen@atmel$(echo .)com \
--cc=ink@jurassic$(echo .)park.msu.ru \
--cc=kyle@mcmartin$(echo .)ca \
--cc=linux-alpha@vger$(echo .)kernel.org \
--cc=linux-am33-list@redhat$(echo .)com \
--cc=linux-kernel@vger$(echo .)kernel.org \
--cc=linux-mips@linux-mips$(echo .)org \
--cc=linux-parisc@vger$(echo .)kernel.org \
--cc=linux-s390@vger$(echo .)kernel.org \
--cc=linux390@de$(echo .)ibm.com \
--cc=linuxppc-dev@lists$(echo .)ozlabs.org \
--cc=linuxppc-dev@ozlabs$(echo .)org \
--cc=mingo@redhat$(echo .)com \
--cc=paulus@samba$(echo .)org \
--cc=ralf@linux-mips$(echo .)org \
--cc=rth@twiddle$(echo .)net \
--cc=schwidefsky@de$(echo .)ibm.com \
--cc=tglx@linutronix$(echo .)de \
--cc=torvalds@linux-foundation$(echo .)org \
--cc=uclinux-dist-devel@blackfin$(echo .)uclinux.org \
--cc=vapier@gentoo$(echo .)org \
--cc=x86@kernel$(echo .)org \
--cc=yasutake.koichi@jp$(echo .)panasonic.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
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