Message-ID: <4B2FCCE3.1090209@redhat.com>
Date: Mon, 21 Dec 2009 11:30:43 -0800
From: Richard Henderson <rth@redhat.com>
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To: Russell King - ARM Linux <linux@arm.linux.org.uk>
CC: Richard Guenther <richard.guenther@gmail.com>,
       David Daney <ddaney@caviumnetworks.com>,
       "gcc@gcc.gnu.org" <gcc@gcc.gnu.org>, Jamie Lokier <jamie@shareable.org>,
       linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
       =?ISO-8859-1?Q?Uwe_Kleine-K=F6nig?= 
	<u.kleine-koenig@pengutronix.de>
Subject: Re: [PATCH] ARM: Convert BUG() to use unreachable()
References: <1260266138-17684-1-git-send-email-u.kleine-koenig@pengutronix.de> <20091217150120.GD24967@shareable.org> <4B2A65C6.7080009@caviumnetworks.com> <84fc9c000912170917y4b2772d0n47bb4dabc74b91ef@mail.gmail.com> <20091217181718.GA4440@n2100.arm.linux.org.uk>
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On 12/17/2009 10:17 AM, Russell King - ARM Linux wrote:
> How is "size-optimal trap" defined?

E.g. Sparc and MIPS have "tcc" instructions that trap based on the
condition codes, and so we eliminate the branch.  That's the only
optimization we apply with __builtin_trap.

> Let me put it another way: I want this function to terminate with an
> explicit NULL pointer dereference in every case.

Then just use that.


r~
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