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From: Roland McGrath <roland@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: 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 14:55:25 -0700 (PDT)	[thread overview]
Message-ID: <20090911215525.12B366A98F@magilla.sf.frob.com> (raw)
In-Reply-To: Andrew Morton's message of  Friday, 11 September 2009 13:45:28 -0700 <20090911134528.cd1782d9.akpm@linux-foundation.org>

> That's a bit of a mouthful.  Did you consider a runtime probe with
> scripts/Kbuild.include's try-run, cc-option, etc?  

I did not see any precedent in the sources for using those to test for
features by compiling particular test sources (i.e. in autoconf style).
I just followed the model I saw.  Those methods seem sufficiently costly
to make it a little questionable to pile on too many more that get
repeated all the time by make, so I just was not opening that can of worms.

As has been mentioned:

	#if __GNUC_MINOR__ > 4

is a sufficient test for the long run.  People using Fedora gcc-4.4 will
not mind applying a trivial kernel patch to get the benefits sooner.


Thanks,
Roland

  parent reply	other threads:[~2009-09-11 21:56 UTC|newest]

Thread overview: 15+ 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
2009-09-11 21:55     ` Roland McGrath [this message]
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  5:52           ` Andrew Morton
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  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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