From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Torvalds Subject: Re: linearize bug? Date: Sat, 27 Aug 2011 10:27:45 -0700 Message-ID: References: <4E588EB8.80808@garzik.org> <4E590F22.6030800@garzik.org> <201108271854.40694.kdudka@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:48385 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750974Ab1H0R2g (ORCPT ); Sat, 27 Aug 2011 13:28:36 -0400 Received: from mail-wy0-f174.google.com (mail-wy0-f174.google.com [74.125.82.174]) (authenticated bits=0) by smtp1.linux-foundation.org (8.14.2/8.13.5/Debian-3ubuntu1.1) with ESMTP id p7RHS6mw024743 (version=TLSv1/SSLv3 cipher=RC4-SHA bits=128 verify=FAIL) for ; Sat, 27 Aug 2011 10:28:08 -0700 Received: by wyg24 with SMTP id 24so3161191wyg.19 for ; Sat, 27 Aug 2011 10:28:05 -0700 (PDT) In-Reply-To: Sender: linux-sparse-owner@vger.kernel.org List-Id: linux-sparse@vger.kernel.org To: Kamil Dudka Cc: Jeff Garzik , Sparse Mailing-list , Pekka J Enberg On Sat, Aug 27, 2011 at 10:13 AM, Linus Torvalds wrote: > > But your patch is fine too. Hmm. There's badness going on with that patch: I can't check the kernel source tree, I get a CHECK arch/x86/kernel/process_64.c sparse: simplify.c:82: if_convert_phi: Assertion `br->cond' failed. so clearly something is screwed up. It happens with your version too, it seems to have gotten triggered by the loop rewriting change. Which *should* have been semantically no difference what-so-ever. But it's been so long, I can't recall all the rules. It may be that trying to linearize the same expression twice (once for the entry condition, once for the loop end) was just something invalid. So the patch is just broken. Never mind. Linus