From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 8280 invoked by alias); 17 Jan 2004 14:49:09 -0000 Mailing-List: contact gcc-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Archive: List-Post: List-Help: Sender: gcc-owner@gcc.gnu.org Received: (qmail 8261 invoked from network); 17 Jan 2004 14:49:08 -0000 Received: from unknown (HELO ams002.ftl.affinity.com) (216.219.253.98) by sources.redhat.com with SMTP; 17 Jan 2004 14:49:08 -0000 Received: from coyotegulch.com ([4.4.125.218]) by ams.ftl.affinity.com with ESMTP id <557156-11823>; Sat, 17 Jan 2004 09:49:05 -0500 Message-ID: <40094B5B.4080306@coyotegulch.com> Date: Sat, 17 Jan 2004 14:49:00 -0000 From: Scott Robert Ladd User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.5) Gecko/20031107 Debian/1.5-3 MIME-Version: 1.0 To: Richard Kenner , gcc mailing list Subject: Re: [RFC] Contributing tree-ssa to mainline References: <10401170328.AA15992@vlsi1.ultra.nyu.edu> In-Reply-To: <10401170328.AA15992@vlsi1.ultra.nyu.edu> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-SW-Source: 2004-01/txt/msg01058.txt.bz2 Richard Kenner wrote: > Sure, but in that situation I feel it should stay in a branch until those > "possibilities" have indeed been "opened up". Otherwise, it's a lot of > extra code to maintain and overhead to pay for in compilation without any > known benefit. Newer is not always better. Indeed I find that for most > of the products I buy, the quality is often *far* worse than that of the > same product purchased decades ago. You are correct. I wish I were more conversant in the internal mechanations of compilers; at the moment, I base my opinion on what I'm told by people who appear to "know their stuff." I have two major interests in the future of GCC: OpenMP and Fortran. When we first created the OpenMP project last year, I was informed that the existing GCC architecture was ill-suited to the task. Therefore, gomp (the GNU OpenMP project) was explicitly founded on tree-ssa. Perhaps someone else (Steven?) can fill in the reasons for this choice. We've already had a debate about back-porting gfortran to the 3.4 architecture; again, others are more qualified to define the technical challenges. What I do know is that the gfortran developers seem very focused on tree-ssa. If we do *not* move SSA into mainline, then we need to discuss how (and if) these important features (Fortran 95 and OpenMP) can be implemented in a timely fashion under the existing architecture. OpenMP will become a major issue within 18 months; regardless of what happens to Fortran, the increasing parallelism in hardware, Intel's strong support of OpenMP, and existing practice in high-performance computing all suggest that this issue is important to GCC. > Whether or not (and to what extent) the tree-ssa infrastructure is > "significant" can't be made by arguments over possibilities it might open > up, but by demonstrating those possibilities. Someone needs to step up and explain why certain new features are only being developed under tree-ssa. Is it due to technical concerns (as I understand it), or not? -- Scott Robert Ladd Coyote Gulch Productions (http://www.coyotegulch.com) Software Invention for High-Performance Computing