All of lore.kernel.org
 help / color / mirror / Atom feed
From: Maarten Lankhorst <maarten.lankhorst@canonical.com>
To: Peter Zijlstra <peterz@infradead.org>,
	Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: mingo@kernel.org, imirkin@alum.mit.edu,
	linux-kernel@vger.kernel.org, daniel.vetter@ffwll.ch,
	robdclark@gmail.com
Subject: Re: [PATCH for 3.12] mutex: Avoid gcc version dependent __builtin_constant_p() usage.
Date: Thu, 17 Oct 2013 12:54:21 +0200	[thread overview]
Message-ID: <525FC1DD.4030205@canonical.com> (raw)
In-Reply-To: <20131017105243.GM2675@laptop.programming.kicks-ass.net>

op 17-10-13 12:52, Peter Zijlstra schreef:
> On Thu, Oct 17, 2013 at 07:45:29PM +0900, Tetsuo Handa wrote:
>> Commit 040a0a37 "mutex: Add support for wound/wait style locks" used
>> "!__builtin_constant_p(p == NULL)" but gcc 3.x cannot handle such expression
>> correctly, leading to boot failure when built with CONFIG_DEBUG_MUTEXES=y.
> So I completely forgot all about this, but wouldn't something like:
>
>  !(__builtin_constant_p(p) && p == NULL)
>
> Not also work and generate the same code?
>
See earlier discussion. It was already answered why that was undesirable. ;)

~Maarten

  reply	other threads:[~2013-10-17 10:54 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-17 10:45 [PATCH for 3.12] mutex: Avoid gcc version dependent __builtin_constant_p() usage Tetsuo Handa
2013-10-17 10:52 ` Peter Zijlstra
2013-10-17 10:54   ` Maarten Lankhorst [this message]
2013-10-17 11:02     ` Peter Zijlstra
2013-10-18 12:51       ` [PATCH for 3.12] mutex: Avoid gcc version dependent__builtin_constant_p() usage Tetsuo Handa
2013-10-18 13:13         ` Ingo Molnar
2013-10-18 15:51           ` Maarten Lankhorst
2013-10-30 13:14             ` [PATCH 3.11-stable] mutex: Avoid gcc version dependent __builtin_constant_p() usage Tetsuo Handa
2013-10-20 19:31 ` [tip:core/urgent] " tip-bot for Tetsuo Handa

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=525FC1DD.4030205@canonical.com \
    --to=maarten.lankhorst@canonical.com \
    --cc=daniel.vetter@ffwll.ch \
    --cc=imirkin@alum.mit.edu \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@kernel.org \
    --cc=penguin-kernel@I-love.SAKURA.ne.jp \
    --cc=peterz@infradead.org \
    --cc=robdclark@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.