From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 15449 invoked by alias); 2 Jun 2009 21:42:12 -0000 Received: (qmail 15440 invoked by uid 22791); 2 Jun 2009 21:42:11 -0000 X-SWARE-Spam-Status: No, hits=-2.4 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS,SPF_PASS X-Spam-Check-By: sourceware.org Received: from mx2.redhat.com (HELO mx2.redhat.com) (66.187.237.31) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 02 Jun 2009 21:42:03 +0000 Received: from int-mx2.corp.redhat.com (int-mx2.corp.redhat.com [172.16.27.26]) by mx2.redhat.com (8.13.8/8.13.8) with ESMTP id n52Lg1D3027454; Tue, 2 Jun 2009 17:42:01 -0400 Received: from ns3.rdu.redhat.com (ns3.rdu.redhat.com [10.11.255.199]) by int-mx2.corp.redhat.com (8.13.1/8.13.1) with ESMTP id n52Lg0mF021572; Tue, 2 Jun 2009 17:42:00 -0400 Received: from freie.oliva.athome.lsd.ic.unicamp.br (sebastian-int.corp.redhat.com [172.16.52.221]) by ns3.rdu.redhat.com (8.13.8/8.13.8) with ESMTP id n52Lfvcw026146; Tue, 2 Jun 2009 17:41:59 -0400 Received: from free.oliva.athome.lsd.ic.unicamp.br (free.oliva.athome.lsd.ic.unicamp.br [172.31.160.1]) by freie.oliva.athome.lsd.ic.unicamp.br (8.14.3/8.14.3) with ESMTP id n52LfvqZ024207; Tue, 2 Jun 2009 18:41:57 -0300 Received: from free.oliva.athome.lsd.ic.unicamp.br (localhost [127.0.0.1]) by free.oliva.athome.lsd.ic.unicamp.br (8.14.3/8.14.3) with ESMTP id n52Lfr1w000659; Tue, 2 Jun 2009 18:41:57 -0300 Received: (from aoliva@localhost) by free.oliva.athome.lsd.ic.unicamp.br (8.14.3/8.14.3/Submit) id n52Lfpfi000657; Tue, 2 Jun 2009 18:41:51 -0300 To: Richard Guenther Cc: Andrew MacLeod , Ian Lance Taylor , gcc-patches@gcc.gnu.org Subject: Re: [trunk<-vta] Re: [vtab] Permit coalescing of user variables References: <4702B1C0.80807@redhat.com> <4A24114D.1000006@redhat.com> <84fc9c000906020254pff2d5a8hc00f022996e7384b@mail.gmail.com> From: Alexandre Oliva Date: Tue, 02 Jun 2009 21:42:00 -0000 In-Reply-To: <84fc9c000906020254pff2d5a8hc00f022996e7384b@mail.gmail.com> (Richard Guenther's message of "Tue\, 2 Jun 2009 11\:54\:10 +0200") Message-ID: User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org X-SW-Source: 2009-06/txt/msg00217.txt.bz2 On Jun 2, 2009, Richard Guenther wrote: > On Mon, Jun 1, 2009 at 9:23 PM, Alexandre Oliva wrote: >> On Jun =C2=A01, 2009, Andrew MacLeod wrote: >>=20 >>> Is there a reason we can't leave the current default behaviour the way >>> it is, and have the VTA code simple enable the "best" choices for it. >>=20 >> We don't want options used to control generation of debug information >> (say the option that enables or disables VTA) to change the generated >> code (say enable or disable coalescing), do we? =C2=A0This would be as b= ad as >> -g/-g0 generating different code. >>=20 >> Personally, I don't see the point of the options either, but I don't see > Me neither, and I am opposed to adding it. I'm missing your rationale here as well. It would help if you at least voiced what you suggest we do instead. Do you propose we keep on sacrificing run-time performance in favor of debug info that users might not even be interested in (say, compile with -O3 -g0), rather than trivially permitting the user to easily tune for one or the other? We don't even have evidence that the current trade-off is useful for users. It sacrifices performance to make for better debug info, but then it screws debug info all over (we inline a lot) to save compile-time performance. We might as well not sacrifice any performance whatsoever, compile- or run-time. That would at least make sense when explained to a user. The =E2=80=9Coh, but if it's inlined, we don't care=E2=80=9D rule that's implem= ented might have made sense when GDB couldn't display info from inlined variables. Now it does, so we can no longer hide behind its shortcoming. --=20 Alexandre Oliva, freedom fighter http://FSFLA.org/~lxoliva/ You must be the change you wish to see in the world. -- Gandhi Be Free! -- http://FSFLA.org/ FSF Latin America board member Free Software Evangelist Red Hat Brazil Compiler Engineer