From: Kyle McMartin <kyle@mcmartin.ca>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Roland McGrath <roland@redhat.com>,
torvalds@linux-foundation.org, jakub@redhat.com,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
x86@kernel.org
Subject: Re: [PATCH 1/2] UNREACHABLE() macro
Date: Fri, 11 Sep 2009 16:59:15 -0400 [thread overview]
Message-ID: <20090911205915.GA19494@bombadil.infradead.org> (raw)
In-Reply-To: <20090911134528.cd1782d9.akpm@linux-foundation.org>
On Fri, Sep 11, 2009 at 01:45:28PM -0700, Andrew Morton wrote:
> On Wed, 9 Sep 2009 19:00:31 -0700 (PDT)
> Roland McGrath <roland@redhat.com> wrote:
>
> > +/*
> > + * __builtin_unreachable is available in GCC 4.5+ and
> > + * also in Fedora/Red Hat GCC 4.4.1-10+.
> > + */
> > +#if (__GNUC_MINOR__ > 4 \
> > + || (__GNUC_MINOR__ == 4 \
> > + && defined __GNUC_RH_RELEASE__ \
> > + && (__GNUC_PATCHLEVEL__ > 1 \
> > + || (__GNUC_PATCHLEVEL__ == 1 \
> > + && __GNUC_RH_RELEASE__ >= 10))))
> > +#define UNREACHABLE() __builtin_unreachable()
> > +#endif
>
> That's a bit of a mouthful. Did you consider a runtime probe with
> scripts/Kbuild.include's try-run, cc-option, etc?
If the crap for determining if it's a RH gcc is removed, then it becomes
really straightforward... Should probably just do that and then apply a
patch to Fedora if it's so damned important it can't just wait for the
next GCC release.
regards, Kyle
next prev parent reply other threads:[~2009-09-11 20:59 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-10 1:59 [PATCH 0/2] __builtin_unreachable Roland McGrath
2009-09-10 2:00 ` [PATCH 1/2] UNREACHABLE() macro Roland McGrath
2009-09-11 20:45 ` Andrew Morton
2009-09-11 20:59 ` Kyle McMartin [this message]
2009-09-11 20:59 ` Kyle McMartin
2009-09-11 21:55 ` Roland McGrath
2009-09-12 3:49 ` Arjan van de Ven
2009-09-12 4:43 ` H. Peter Anvin
2009-09-12 5:30 ` Arjan van de Ven
2009-09-12 5:30 ` Arjan van de Ven
2009-09-12 5:52 ` Andrew Morton
2009-09-12 6:38 ` Jakub Jelinek
2009-09-12 6:38 ` Jakub Jelinek
2009-09-13 20:10 ` H. Peter Anvin
2009-09-10 2:01 ` [PATCH 2/2] x86: BUG(): use UNREACHABLE() Roland McGrath
2009-09-10 2:01 ` Roland McGrath
2009-09-10 4:42 ` [PATCH 0/2] __builtin_unreachable Américo Wang
2009-09-10 6:42 ` H. Peter Anvin
2009-09-10 6:13 ` Jakub Jelinek
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