From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758982AbXERXGR (ORCPT ); Fri, 18 May 2007 19:06:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755821AbXERXGE (ORCPT ); Fri, 18 May 2007 19:06:04 -0400 Received: from mailout.stusta.mhn.de ([141.84.69.5]:38207 "EHLO mailhub.stusta.mhn.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755626AbXERXGD (ORCPT ); Fri, 18 May 2007 19:06:03 -0400 Date: Sat, 19 May 2007 01:05:49 +0200 From: Adrian Bunk To: Andrew Morton Cc: Thomas Gleixner , Ingo Molnar , "bugme-daemon@kernel-bugs.osdl.org" , linux-kernel@vger.kernel.org, malitzke@metronets.com, Linus Torvalds Subject: Re: [Bug 8501] udivdi3 absence with gcc-4.3.0 on kernels 2.6.20.11 & 2.6.22.-rc1 Message-ID: <20070518230549.GB6291@stusta.de> References: <200705181941.l4IJfOtf018049@fire-2.osdl.org> <20070518152935.b5a4b3bf.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20070518152935.b5a4b3bf.akpm@linux-foundation.org> User-Agent: Mutt/1.5.15+20070412 (2007-04-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 18, 2007 at 03:29:35PM -0700, Andrew Morton wrote: >... > I expect that this optimisation will remain in gcc-4.3 and we'll end up > having major kernel releases which don't build on i386 with major gcc > releases, which isn't altogether desirable. I suspect we'll need to fix this > fairly urgently, and to backport the fix into a number of kernel releases. >... Building old kernels with the latest gcc has never worked [1]. First of all, gcc 4.3 is still one year away from being released, so there's zero urgency. And considering that compile errors are the trivial things, and the real problems are new runtime errors caused by incorrect kernel code combined with gcc optimization [2] I'd even consider backporting only the compile fixes before the real issues have been shaken out a bad idea. cu Adrian [1] the backported gcc 4 support in kernel 2.4 is an exception [2] look e.g. at commit 8690ba446defe2e2b81803756c099d2943dfd5fd -- "Is there not promise of rain?" Ling Tan asked suddenly out of the darkness. There had been need of rain for many days. "Only a promise," Lao Er said. Pearl S. Buck - Dragon Seed