Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754674AbXLCMEQ (ORCPT ); Mon, 3 Dec 2007 07:04:16 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751833AbXLCMEF (ORCPT ); Mon, 3 Dec 2007 07:04:05 -0500 Received: from www.tglx.de ([62.245.132.106]:50087 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751455AbXLCMEC (ORCPT ); Mon, 3 Dec 2007 07:04:02 -0500 Date: Mon, 3 Dec 2007 13:03:28 +0100 (CET) From: Thomas Gleixner To: Jakub Jelinek cc: Thomas Gleixner , Pierre Ossman , LKML Subject: Re: Fedora's latest gcc produces unbootable kernels In-Reply-To: <20071203115112.GT16835@devserv.devel.redhat.com> Message-ID: References: <20071201154223.1b052d39@poseidon.drzeus.cx> <20071201184752.33536d09@poseidon.drzeus.cx> <20071201212054.2377c8be@poseidon.drzeus.cx> <23803.203.197.163.97.1196669842.squirrel@www.tglx.de> <20071203085817.GQ16835@devserv.devel.redhat.com> <20071203115112.GT16835@devserv.devel.redhat.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1126 Lines: 27 On Mon, 3 Dec 2007, Jakub Jelinek wrote: > On Mon, Dec 03, 2007 at 12:34:17PM +0100, Thomas Gleixner wrote: > > Of course just to annoy you :) > > It doesn't matter whether I'm annoyed about this or not, but whether gcc is > able to generate decent code with it or not. And especially with union it > is not, at least through all the tree ssa passes. You already have a lot of > the details hidden in ktime.h accessor inlines, so I don't think it would be > hard to add further one or two. > > Anyway, even just using typedef struct ktime { s64 tv64; } ktime_t; could > make things better in case you have just one field. Unlike unions, structs > can be (and in this case most likely will be) scalarized by SRA, so > half of tree SSA passes will see it as integral var and will be able to > perform optimizations on it. Makes sense. I look into fixing that. Thanks, tglx -- 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/