From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758049AbZDOHhs (ORCPT ); Wed, 15 Apr 2009 03:37:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752511AbZDOHhh (ORCPT ); Wed, 15 Apr 2009 03:37:37 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:53931 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752425AbZDOHhg (ORCPT ); Wed, 15 Apr 2009 03:37:36 -0400 Date: Wed, 15 Apr 2009 09:37:20 +0200 From: Ingo Molnar To: Steven Rostedt Cc: Johannes Berg , Ingo Molnar , LKML Subject: Re: TRACE_BRANCH_PROFILING breaks gcc warnings Message-ID: <20090415073720.GC18192@elte.hu> References: <1239748090.4205.26.camel@johannes.local> <1239748293.21121.60.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1239748293.21121.60.camel@localhost.localdomain> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Steven Rostedt wrote: > > On Wed, 2009-04-15 at 00:28 +0200, Johannes Berg wrote: > > With TRACE_BRANCH_PROFILING enabled you get "dummy may be used > > uninitialised" with code like the following (and gcc 4.3.3): > > > > void *dummy, *c; > > > > if (a && (dummy = b())) > > c = dummy; > > > > Therefore, allyesconfig has become useless for looking at warnings. There's an easy solution for that problem btw: you just have to disable the branch tracer after allyesconfig. [ Or fix the compiler. Or both ;-) ] I'm also curious, how often do you do allyesconfig builds? I've never seen you report one before. Have you started doing them recently? How much time does it take on your system? > > :( > > This has been mentioned before, and I've asked about sending a > patch that would prevent TRACE_BRANCH_PROFILING from being > selected with an allyesconfig. > > It is easy to do. I could make it a selection and not a boolean > and it will not select it as default, even for allyes/modconfig > > Thoughts? That's a good idea - please send a patch. Ingo