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Message-ID: <4B30AE8E.8060805@gnu.org>
Date: Tue, 22 Dec 2009 12:33:34 +0100
From: Paolo Bonzini <bonzini@gnu.org>
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To: Richard Guenther <richard.guenther@gmail.com>
CC: David Daney <ddaney@caviumnetworks.com>,
       Jamie Lokier <jamie@shareable.org>, "gcc@gcc.gnu.org" <gcc@gcc.gnu.org>,
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	<u.kleine-koenig@pengutronix.de>,
       linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
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>
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On 12/17/2009 06:17 PM, Richard Guenther wrote:
> It shouldn't as *(int *)0 = 0; might trap.  But if you want to be sure
> use
>     __builtin_trap ();
> instead for the whole sequence (the unreachable is implied then).
> GCC choses a size-optimal trap representation for your target then.

Agree that it shouldn't but just to be sure I'd use

   *(volatile int *)0 = 0;
   unreachable ();

Paolo
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