From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by finch.gentoo.org (Postfix) with ESMTPS id 05F78138334 for ; Sat, 22 Sep 2018 05:58:16 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id D4BEFE082B; Sat, 22 Sep 2018 05:58:10 +0000 (UTC) Received: from mail-ot1-f66.google.com (mail-ot1-f66.google.com [209.85.210.66]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 90001E07D9 for ; Sat, 22 Sep 2018 05:58:10 +0000 (UTC) Received: by mail-ot1-f66.google.com with SMTP id q4-v6so1981830otf.13 for ; Fri, 21 Sep 2018 22:58:10 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:content-transfer-encoding; bh=yGmmvn3eKhgk0hHw4fbDfbT76kRHhY3nmbBKJzmn79M=; b=YeokmoyykpD3jm+/HWyU/jJ49kHKwIXBCPdyjyLqexJOD7IHFCsDUQuZxoI/O8Hij/ ggGVuX5XRwB3u37kg9Shva5jNtEs3eDjlYv/RUNaGSvfIKYH+3SS/kVVbZQ3ySwz1rqh GgIav8PdEJzwoRG4AO6SawABaBNqBKKvKQ16rc3TwriXpAqlVeRROfjOzITSb0QE994O lqtG9audAGZVLxrk+KWdZ2i+MNA/CYgxhHFoqgovrrdWxPmcqlU7TU4j9QvEgifBfR8M Gsm7JHMdwC7puMhpIO9lhEMGLK+g3ibe56WgnxTKtszbaX6QfSAewkj9nnsgq6XZosRi tPDw== X-Gm-Message-State: ABuFfojo1rjl5TS1DuRdcOZtXQcil4Dm1DlmHfEm0RFRYH+YX+ZynuKO gDjOjrvRqpQwLlq1OCvss9q7vanAbNXx0AXeToewLQ== X-Google-Smtp-Source: ACcGV60SBiih4TkA2B/dC6lrhY77Yd2MvkbIUK4+lRdQHxF/XxBJcbryq76HuHOZN2oXr02SqJqYdWUrkannpv+Kx44= X-Received: by 2002:a9d:3ea3:: with SMTP id b32-v6mr607756otc.208.1537595889291; Fri, 21 Sep 2018 22:58:09 -0700 (PDT) Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-dev@lists.gentoo.org Reply-to: gentoo-dev@lists.gentoo.org MIME-Version: 1.0 References: <20180909143221.21d784d02f51623e8c57c545@gentoo.org> <1536510660.863.9.camel@gentoo.org> <20180910074539.GA6512@baraddur.perfinion.com> <0d8b7f02-9c38-969c-413b-69d4dee6ca89@gentoo.org> <20180912085649.GA16516@baraddur.perfinion.com> <6c18c6bd-4cf3-dff6-2f20-c021063e01fa@gentoo.org> <20180913160347.GC26329@gentoo.org> <4FCF42AC-6B48-40F6-8B98-79CF71789A6A@gentoo.org> <3A8A39E8-91DF-40B2-8958-F046FA58622B@gentoo.org> <20180915000753.19a8715f@sf> <60E4E63B-6582-4C4D-B20D-A791874ADE63@gentoo.org> In-Reply-To: From: Alon Bar-Lev Date: Sat, 22 Sep 2018 08:57:56 +0300 Message-ID: Subject: Re: [gentoo-dev] Changing policy about -Werror To: gentoo-dev@lists.gentoo.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Archives-Salt: 379c0689-ff5e-4731-894d-06382459235d X-Archives-Hash: e9237217beffb2c36087b63b8b7f29f2 On Sat, Sep 22, 2018 at 1:33 AM Ch=C3=AD-Thanh Christopher Nguy=E1=BB=85n wrote: > > Richard Yao schrieb: > > >> To make code behave differently it needs substantial amount of code > >> to provide you an example. You need to him O2<->O3 behaviour delta > >> after all. But I will try (for a different warning, it should not matt= er > >> much). > > Thanks. I had been incorrect about -O3 giving not us some additional in= formation for warnings. My apologies for the confusion. > >> > >> Below is a reduced example of a larger C++ program. > >> Many thanks to Ulya for providing recent example! > > Not that it matters now, but there are examples of packages building at -= O2 > but failing to build at -O3 optimization levels, due to -Werror. > > One is dev-libs/libcss: https://bugs.gentoo.org/626752 > It is matter, and shows that for selected packages in which upstream has strict policy of no warning, each warning should be investigated as it may be a true issue. The tool compiler provide to find these edge condition should not be ignored nor overridden. The fact that a package "builds" does not mean it is free of bugs. Regards, Alon