Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754543Ab0KHLUs (ORCPT ); Mon, 8 Nov 2010 06:20:48 -0500 Received: from mail-iw0-f174.google.com ([209.85.214.174]:44314 "EHLO mail-iw0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754475Ab0KHLUq convert rfc822-to-8bit (ORCPT ); Mon, 8 Nov 2010 06:20:46 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=Bny2H5rxFTR8YnGcqiMlCofqF5qYkjGmCZ9gIum8/z8WJj1zF2sBO2JllnpxIizr4R jfh0W0BbYfuAEhtmwgFdDvvj6K3bj+W+rfQX3eat86czRSGcwFgKsy9J5ygSXUeWE5Cv IAgkONof1QkmvV8RTB1Xzv/jnSC4ewEK+rL5I= MIME-Version: 1.0 In-Reply-To: <877hgorrj1.fsf@basil.nowhere.org> References: <4CD538CA.8010901@xs4all.nl> <87wroostw3.fsf@basil.nowhere.org> <87k4kospnd.fsf@basil.nowhere.org> <877hgorrj1.fsf@basil.nowhere.org> Date: Mon, 8 Nov 2010 12:20:46 +0100 Message-ID: Subject: Re: gcc 4.5.1 / as 2.20.51.0.11 miscompiling drivers/char/i8k.c ? From: Richard Guenther To: Andi Kleen Cc: Andreas Schwab , Jim , Linux Kernel Mailing List , gcc@gcc.gnu.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1090 Lines: 35 On Mon, Nov 8, 2010 at 12:20 PM, Andi Kleen wrote: > Richard Guenther writes: > >> On Mon, Nov 8, 2010 at 12:03 AM, Andi Kleen wrote: >>> Andreas Schwab writes: >>>> >>>> The asm fails to mention that it modifies *regs. >>> >>> It has a memory clobber, that should be enough, no? >> >> No. ?A memory clobber does not cover automatic storage. > > That's a separate problem. > >> Btw, I can't see a testcase anywhere so I just assume Andreas got >> it right as usual. > > An asm with live inputs and outputs should never be optimized > way. If 4.5.1 started doing that it's seriously broken. Please provide a testcase, such asms can be optimized if the outputs are dead. Richard. > -Andi > > -- > ak@linux.intel.com -- Speaking for myself only. > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/