From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id B45323858D28 for ; Tue, 22 Aug 2023 08:34:15 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org B45323858D28 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1692693255; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=dc6IzSwXbIrYGVGBUvyIWXvl3zRimCZu/DUwN55j3pY=; b=gxaxncHojBDhtZnJlVlp50v09Bn45YWgg7WyIxJwlwKvVAG9aHdo/93GHzZLq2nzbtw/wt 0Aa0+105qO5k6k4Bi9eSdR2TfF0NKM87GVjIPxkLHJ/MGeYDOY2UIiVxvE83VD/1ybE+Ix kuhrUOjlsw5xOtC5TRcnW1saz1Ra0FE= Received: from mimecast-mx02.redhat.com (66.187.233.73 [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-558-WgJvBoJINsCYJRy5pQ7wyg-1; Tue, 22 Aug 2023 04:34:11 -0400 X-MC-Unique: WgJvBoJINsCYJRy5pQ7wyg-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 575102A5956E; Tue, 22 Aug 2023 08:34:11 +0000 (UTC) Received: from tucnak.zalov.cz (unknown [10.45.225.165]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1C76164687; Tue, 22 Aug 2023 08:34:11 +0000 (UTC) Received: from tucnak.zalov.cz (localhost [127.0.0.1]) by tucnak.zalov.cz (8.17.1/8.17.1) with ESMTPS id 37M8Y9tJ2416315 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Tue, 22 Aug 2023 10:34:09 +0200 Received: (from jakub@localhost) by tucnak.zalov.cz (8.17.1/8.17.1/Submit) id 37M8Y8Vk2416314; Tue, 22 Aug 2023 10:34:08 +0200 Date: Tue, 22 Aug 2023 10:34:08 +0200 From: Jakub Jelinek To: Richard Biener Cc: "Jiang, Haochen" , ZiNgA BuRgA , Hongtao Liu , "gcc-patches@gcc.gnu.org" Subject: Re: Intel AVX10.1 Compiler Design and Support Message-ID: Reply-To: Jakub Jelinek References: <20230808071312.1569559-1-haochen.jiang@intel.com> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Spam-Status: No, score=-3.7 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H4,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On Tue, Aug 22, 2023 at 09:36:15AM +0200, Richard Biener via Gcc-patches wrote: > I think internally we should have conditional 512bit support work across > AVX512 and AVX10. > > I also think it makes sense to _internally_ have AVX10.1 (10.1!) just > enable the respective AVX512 features. AVX10.2 would then internally > cover the ISA extensions added in 10.2 only. Both would reduce the > redundancy and possibly make providing inter-operation between > AVX10.1 (10.1!) and AVX512 to the user easier. I see AVX 10.1 (10.1!) > just as "re-branding" latest AVX512, so we should treat it that way > (making it an alias to the AVX512 features). > > Whether we want allow -mavx10.1 -mno-avx512cd or whether > we only allow the "positive" -mavx512f -mavx512... (omitting avx512cd) > is an entirely separate > question. But I think to not wreck the core idea (more interoperability, > here between small/big cores) we absolutely have to > provide a subset of avx10.1 but with disabled 512bit vectors which > effectively means AVX512 with disabled 512bit support. Agreed. And I still think -mevex512 vs. -mno-evex512 is the best option name to represent whether the effective ISA set allows 512-bit vectors or not. I think -mavx10.1 -mno-avx512cd should be fine. And, -mavx10.1-256 option IMHO should be in the same spirit to all the others a positive enablement, not both positive (enable avx512{f,cd,bw,dq,...} and negative (disallow 512-bit vectors). So, if one uses -mavx512f -mavx10.1-256, because the former would allow 512-bit vectors, the latter shouldn't disable those again because it isn't a -mno-* option. Sure, instructions which are specific to AVX10.1 (aren't present in any currently existing AVX512* ISA set) might be enabled only in 128/256 bit variants if we differentiate that level. But, if one uses -mavx2 -mavx10.1-256, because no AVX512* has been enabled it can enable all the AVX10.1 implied AVX512* parts without EVEX.512. Jakub