From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from esa1.mentor.iphmx.com (esa1.mentor.iphmx.com [68.232.129.153]) by sourceware.org (Postfix) with ESMTPS id 07B28385841D for ; Wed, 1 Sep 2021 09:11:05 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 07B28385841D Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=codesourcery.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=mentor.com IronPort-SDR: iPKOI5z/RjQlJxSPgs4ZZdwdd7Ec3spRdBo28/DqMhfquBM9MMFb3qDog5hWAfYyoIqg0UdTWq /zUMqBpJ3Qif/8oSnseT2A8Biw56+Yv0/Bt7G2rgRJFW/Nu3HaNLavjA+Xu2vrZzySg4imvGCo TKtn/zoo2Ei4xP6KMvJSSTvevjHMlMi1Rv+T7qCkuPMLuUikTBjKmOCpUymqFQc0YjDqHFNMyG 6xQeTE1NkdXsDeljubs6YS2y9CIKp1cMVLYK4ufco62ieEeMIGfBXlmm3SduN4FF9obwSwlDn1 99frJXZkUNWF/uljrodUuN4H X-IronPort-AV: E=Sophos;i="5.84,368,1620720000"; d="scan'208";a="67850109" Received: from orw-gwy-02-in.mentorg.com ([192.94.38.167]) by esa1.mentor.iphmx.com with ESMTP; 01 Sep 2021 01:11:05 -0800 IronPort-SDR: PfDbHvhwjHAK0942A2GAQAhY9OhzJFKddgGzcvRjFM6kMfdYAlY5H64q+SvQcfZh+FITXh3Pxl 2ct3kL+hafL0E5vOG5mrVQZ5LiC8EsfF3zIb4cnvUkcYUeMYumStRNApNOBHyvWq4lNlEsSRPv f9g3vO8IWVU4QwWW3pIEorYSs2e+XTPLq4m0jCV2oXPqpnVj0fC5s1Cr800XIxZYDSUdUbtVW6 8F3Hrz31+wWx/ySDxo4gIIKWkxLilwb9XAE36gSIU3pJJs7OPHQK30oxCQ/c1HW6E+YaxrjGLh +6M= Subject: Re: Enable the vectorizer at -O2 for GCC 12 To: Jeff Law , Hongtao Liu , Kewen.Lin CC: Florian Weimer , Jakub Jelinek , , Segher Boessenkool , GCC Development , Richard Sandiford , , Hongtao Liu References: <87v93nozh7.fsf@oldenburg.str.redhat.com> <0e35169d-b9df-f665-dbc1-a3e76a3e7d8e@linux.ibm.com> <2ab5dd7f-3170-a0fc-e3e4-6376510f89ea@linux.ibm.com> From: Andrew Stubbs Message-ID: <5dc405f9-2f29-d3c6-c6ff-1dfba39caac5@codesourcery.com> Date: Wed, 1 Sep 2021 10:10:57 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 8bit X-Originating-IP: [137.202.0.90] X-ClientProxiedBy: svr-ies-mbx-09.mgc.mentorg.com (139.181.222.9) To svr-ies-mbx-01.mgc.mentorg.com (139.181.222.1) X-Spam-Status: No, score=-5.9 required=5.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, KAM_DMARC_STATUS, KAM_NUMSUBJECT, NICE_REPLY_A, SPF_HELO_PASS, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: gcc@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 01 Sep 2021 09:11:08 -0000 On 31/08/2021 05:13, Jeff Law wrote: > > > On 8/30/2021 9:30 PM, Hongtao Liu via Gcc wrote: >> On Tue, Aug 31, 2021 at 11:11 AM Kewen.Lin via Gcc >> wrote: >>> on 2021/8/30 下午10:11, Bill Schmidt wrote: >>>> On 8/30/21 8:04 AM, Florian Weimer wrote: >>>>> There has been a discussion, both off-list and on the gcc-help mailing >>>>> list (“Why vectorization didn't turn on by -O2”, spread across several >>>>> months), about enabling the auto-vectorizer at -O2, similar to what >>>>> Clang does. >>>>> >>>>> I think the review concluded that the very cheap cost model should be >>>>> used for that. >>>>> >>>>> Are there any remaining blockers? >>>> Hi Florian, >>>> >>>> I don't think I'd characterize it as having blockers, but we are >>>> continuing to investigate small performance issues that arise with >>>> very-cheap, including some things that regressed in GCC 12.  Kewen >>>> Lin is leading that effort.  Kewen, do you feel we have any major >>>> remaining concerns with this plan? >>>> >>> Hi Florian & Bill, >>> >>> There are some small performance issues like PR101944 and PR102054, and >>> still two degraded bmks (P9 520.omnetpp_r -2.41% and P8 526.blender_r >>> -1.31%) to be investigated/clarified, but since their performance >>> numbers >>> with separated loop and slp vectorization options look neutral, they are >>> very likely noises.  IMHO I don't think they are/will be blockers. >>> >>> So I think it's good to turn this on by default for Power. >> The intel side is also willing to enable O2 vectorization after >> measuring performance impact for SPEC2017 and eembc. >> Meanwhile we are investigating PR101908/PR101909/PR101910/PR92740 >> which are reported O2 vectorization regresses extra benchmarks on >> znver and kabylake. > We'd like to see it on for our processor as well.  Though I don't have > numbers I can share at this time. AMD GCN probably ought to have it on too, possibly set to maximum ... a GPU without vectors is pretty terrible. Andrew