From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757393AbcG1U2Y (ORCPT ); Thu, 28 Jul 2016 16:28:24 -0400 Received: from mail-wm0-f66.google.com ([74.125.82.66]:35056 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751304AbcG1U2W (ORCPT ); Thu, 28 Jul 2016 16:28:22 -0400 Date: Thu, 28 Jul 2016 22:28:14 +0200 From: Ingo Molnar To: Linus Torvalds Cc: Borislav Petkov , Sam Ravnborg , lkml , Michael Matz , Linux Kbuild mailing list , x86-ml Subject: Re: [PATCH] Kbuild: Move -Wmaybe-uninitialized to W=1 Message-ID: <20160728202814.GA16950@gmail.com> References: <20140616132045.GE8170@pd.tnic> <20140616211405.GA7914@ravnborg.org> <20140624213835.GD15068@pd.tnic> <20140707105339.GA4776@pd.tnic> <20160728042011.GA25498@nazgul.tnic> <20160728082915.GA2349@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Linus Torvalds wrote: > On Thu, Jul 28, 2016 at 12:03 PM, Linus Torvalds > wrote: > > > > Once we get to the point that the warning is no longer useful, and is more > > pain than gain, it gets disabled. > > Btw, I have a suspicion that you didn't realize that "-Wmaybe-uninitialized" is > separate from "-Wuninitialized" (which is *not* disabled). I very much know the difference, as you can see from the commit IDs I cited. > The "maybe-uninitialized" warning is literally gcc saying "I haven't really > followed all the logic, but from my broken understanding it isn't _obvious_ that > it is initialized". > > And the problem is that a lot of gcc optimization choices basically move the > pointer of "obvious". So the warning is a bit random to begin with. And when the > gcc people screw thigns up, things go to hell in a handbasket. Fair enough. Thanks, Ingo