From mboxrd@z Thu Jan  1 00:00:00 1970
From: "H. Peter Anvin" <hpa@kernel.org>
Subject: Re: [PATCH 0/2] __builtin_unreachable
Date: Wed, 09 Sep 2009 23:42:34 -0700
Message-ID: <4AA89FDA.3090105@kernel.org>
References: <20090910015923.8FB628AE5F@magilla.sf.frob.com> <2375c9f90909092142i58595fedod6780a7c41190f5f@mail.gmail.com>
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Cc: Roland McGrath <roland@redhat.com>, Andrew Morton <akpm@linux-foundation.org>, Linus Torvalds <torvalds@linux-foundation.org>, Jakub Jelinek <jakub@redhat.com>, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, x86@kernel.org

On 09/09/2009 09:42 PM, Am=C3=A9rico Wang wrote:
>=20
> Just curious, what different asm code will gcc generate for this? Com=
paring it
> to for(;;) ? I am sorry that I don't have gcc 4.5 on hand.
>=20

It generates nothing.  It is you as the programmer guaranteeing that we
will never get there, and as such gcc will generate no code at all.

	-hpa