From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from EUR03-AM7-obe.outbound.protection.outlook.com (mail-am7eur03on2053.outbound.protection.outlook.com [40.107.105.53]) by sourceware.org (Postfix) with ESMTPS id 40B4E3858D32 for ; Tue, 18 Oct 2022 05:33:26 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 40B4E3858D32 Authentication-Results: sourceware.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=suse.com ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=Jq/TFTtq7035RFdyW5UgmYbgnYNzfUYsGGpGvRNdDedhyseRN50F/SrF7IgULa4LU0AcAX++QTb8NUODSkq7QXua4ONjKJq2Il88V2dfusdcqeI2pqfrYfyC5szS6UxSP6bxk6sAwnoE9eMBEIznHZbOCwoc2dZ6fdonukSPc7GD9xArOt4ih4VZr7DeFKfSmnF8KlM09cNUiGLEl2cYtgLg+v2n9XbvhqAlDuP6wf3paPd4OElgPmMIiXCdY5jA9uvoNdxN2Wb0w9kIiIUhOoO19ZB5Eed+IubL6QbUmi9xpEJlxntSx6dYGIoBHgRB7aYDKLo1uNg4iipJp9KEZg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=u2kjZq8P0m7S/p1t5O+ndwnoTb/D5ibHuV1oMNNq0ec=; b=YiJ89ULrOVoHBVC7n+VYU6rOA04XgKZx9Nx3+8sEkEKRpBg+y/B2FrDDdnxQ4jo9xaEHZNqB3nFsIsszgXK14bcZFUBaFqwpxgYrfUzs6UNry0flGH9h3wUfLMYbFf8ugFtuMu0Cd4ja9EP2wIf+Q1CIPyEA6omfKeYfA8fAfH022FpvNHqxgFCQcmfwT9u1OuXQ5Btj93d7UJ6ip8+Reb5JqeaSPba6VlkX3dk02N8QeAbBJPqIsCXy+OwbUYX/3+tuExugAjl6oRL3t9g4JD/PJBE7m5fA28J3Ob4FJFqVxJu1zTJ2X0wh/A3rKK2mq/vRCaH9WH/CU229JpBSUA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=suse.com; dmarc=pass action=none header.from=suse.com; dkim=pass header.d=suse.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=u2kjZq8P0m7S/p1t5O+ndwnoTb/D5ibHuV1oMNNq0ec=; b=tN4kUu5T1cJRBjAeeHQdJoqO54pkZOgWNvz+RTxbHC2t+nbQYotplQrSM8SAgRraHd6FM3+hJuh+8blCpgptbOJwcfh7dJbYOBuK2VRmcE7x8SeQsjQVNmo+dd762+mupLCkdknyxWtiTkyNUE7Yw50txWDUzgzqtcBWPPgG5hLHr2VQ0N6FKpiXJSUf//+Vr1V8tBctK26e+qDLJ6sU7y7BAe4l9X6ExbLM3V4YL1Us5KFgvOv5MW08epcooX/9j7oZfh/URVhXvrJ3qTFdhrp3nci73c5AzmPTGUhrOeLON6U1jqn9jjjWjjUKkOGYShxkdo66t8OOoMGvImxmZw== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=suse.com; Received: from VE1PR04MB6560.eurprd04.prod.outlook.com (2603:10a6:803:122::25) by AS8PR04MB7750.eurprd04.prod.outlook.com (2603:10a6:20b:2aa::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5723.26; Tue, 18 Oct 2022 05:33:24 +0000 Received: from VE1PR04MB6560.eurprd04.prod.outlook.com ([fe80::2459:15ae:e6cb:218a]) by VE1PR04MB6560.eurprd04.prod.outlook.com ([fe80::2459:15ae:e6cb:218a%7]) with mapi id 15.20.5723.033; Tue, 18 Oct 2022 05:33:24 +0000 Message-ID: <6d3a01b1-2576-f329-0a36-486526c0b03b@suse.com> Date: Tue, 18 Oct 2022 07:33:21 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.3.3 Subject: Re: [PATCH 01/10] Support Intel AVX-IFMA Content-Language: en-US To: "H.J. Lu" Cc: Haochen Jiang , wwwhhhyyy , binutils@sourceware.org References: <20221014091248.4920-1-haochen.jiang@intel.com> <20221014091248.4920-2-haochen.jiang@intel.com> <863655db-f202-477f-c638-00773c25886c@suse.com> From: Jan Beulich In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ClientProxiedBy: AS8PR07CA0052.eurprd07.prod.outlook.com (2603:10a6:20b:459::13) To VE1PR04MB6560.eurprd04.prod.outlook.com (2603:10a6:803:122::25) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: VE1PR04MB6560:EE_|AS8PR04MB7750:EE_ X-MS-Office365-Filtering-Correlation-Id: 16608299-f5a1-4667-581d-08dab0ca469e X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:VE1PR04MB6560.eurprd04.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230022)(376002)(136003)(346002)(366004)(396003)(39860400002)(451199015)(6486002)(6916009)(2616005)(186003)(83380400001)(41300700001)(86362001)(31696002)(38100700002)(5660300002)(2906002)(4326008)(6666004)(8676002)(6512007)(478600001)(53546011)(6506007)(316002)(66556008)(66476007)(66946007)(8936002)(31686004)(36756003)(54906003)(43740500002)(45980500001);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?WmpCQW83VytNQmpHSnBaL2M2VUMwQXlwSUZBb0NxTHlxK2E5WTFaYm5mMVRY?= =?utf-8?B?dXk0RWtrTlNnWWZVZnhseUpKRGpkc3ZVdmNFUnl3UkpmQTBoejRQOWpXZGx1?= =?utf-8?B?U3M3VTBwNmp1N3VITGhNL3VHWDJHMFp1SE1tVm5IZHZwOGdCaktqRDk5ZUFv?= =?utf-8?B?MjRkNnE1L3pPODVrbHVrQ0dkNVMyTmZwQUt6NGkrQmhWc1MwZlpETHNnbkJ2?= =?utf-8?B?Nlg4SGIxZkJLRXBSVCs0dUlwZk1pSlBrK3JCb0QwSmZyR1ErVHJKWklWVGZk?= =?utf-8?B?Qk5ucU94VnhCNGVZRGlGWDNNYjZzaExlT3Jpb2VyTUliUnZZRE1EZ0FJZTA1?= =?utf-8?B?Zk5mUjNDUXZQdzFaMmY0ei9ZMDhIdTFRQUdRVWN6aEwwVCtmNlZzTHVOY0o1?= =?utf-8?B?Uzk4SlFkYzdVN1czREpHMTNJN0FUV0VSZzFUeE1CNWpkZkpxUmQ3VEFGVmsr?= =?utf-8?B?dmdiak5ZalhzR2k5UmNHTTF2UG92cnFiNFdzVVlqaWdxeG0vRGZLUkx2cURD?= =?utf-8?B?Y0VQMkZYRkVwamI1cHpuQTVkVVBEZytMUXRyK3ZxT0ZFZXJEZlNmLytkTW5W?= =?utf-8?B?eGsrNFEra0Z6NXQ4UjZKNjF3SndOZkh0VHNoMzJtYVR3K3RuT21KVmVrRnEr?= =?utf-8?B?d3FYdUxCdmpGbUdwa1dnY1B0aTJYMkZnVVpuM0tSWFZQRGY3bFd0OUY1Mkdr?= =?utf-8?B?NlVWVENnbXZFTVd1bS9hOGpmZlF4VHhKazZqUXFvTWNsdmFyaGJ2amtVUUxM?= =?utf-8?B?MXdPRWo3ZjJnVDUxSjRNN2VVQnNDdldFelhsNnU2elIrWmV2REhVdzJCTmNv?= =?utf-8?B?MmZiVXF5blNZS2VPOVRlWDBjU3gxTTg0YkJ5SElWQmtmOERCQVJrNFBhSmRZ?= =?utf-8?B?cy85OWlZaHYvVjYyMkFnK1FPMUhRRUlLaUgwTGJwUWRXb2M4bm1FdkVBd0ly?= =?utf-8?B?NFJQUFcrMnhNeTliQjUzQzcvcDBLZlI2OFh2aVJZVmc0RHFmTlVaaC9aQW9S?= =?utf-8?B?MHlyck11MTJRRnlqT3BsOXJTaG1IcGkwdjNZeGhRM0tDbHpoVVZtOG1NUWEz?= =?utf-8?B?SmV4WHREVkJ6M2xlM2gzMlRjWGVuTkhHZWlQOHZZa2F3K3B5aTM0Vm5KdTc1?= =?utf-8?B?ZTk3dFdUYlV4YXErTDZBY0R4NEkyWnI3T0dUN0xsRW8zRGIzOXZQalVxeGRm?= =?utf-8?B?dXAraUZNdDZPRlo4S2tnc2N5L3haL29YU2c3MXVnVk1HaEFubEVTM0pjcy9G?= =?utf-8?B?Q1prd1JFQWhjbEJNQldOYkFrUm5TTXNERmVhaHM2ci95MHRiWXI3UllqRmtu?= =?utf-8?B?WlJxMXgzc09HRTdzbS9ERGhlVUhrWXl2QVduN25laGd5TVJ3TSsrYnFuUVlE?= =?utf-8?B?L2kwRDlGWmR3aHZhSWVWYUxnMlREd0tzZUs3RTR0NXVoZFRYeER4RGNCV3Ft?= =?utf-8?B?L0o4dDg2RzA2bUlEbWdhSUN1bWF3eWVNSW02ZkV3c3FSZXVtbldDR3lvbDRQ?= =?utf-8?B?b0szam9SaVZianpqUzQ3THZQeTV4aml2SDdXOXlMckg4SnlMbzFXRkVuUUFJ?= =?utf-8?B?UHNQMklvSFp4bE0xdG51eGFtdGsxWlpVcTZwZTB2VFpNNSt3ejRHMU1KRko5?= =?utf-8?B?ZHV5VU1oOTRRaThSTnpFaERKVnJyYUxyL1dsUExOaWVnZ1p0dW5jSVZVbHV3?= =?utf-8?B?c1NjbGEwSTNoS21LQVlJejE1eGR4QlU2QnU3MmhIb2lyWE96MU1Tc0txQWc4?= =?utf-8?B?d2JFVmxVQ1gvYXRMRGZPSTZ3RFBJTDBodGVaeVFDWEhvd1A5T3lZUGtlT3V0?= =?utf-8?B?WlBwYnJzT3AwNExZeU41OEFyT3ZJR0xpRVExeE1ZTmR3ZEFWWTkzYzc0NDNl?= =?utf-8?B?YUtNWG9PTFhHMllZVS81S2hCT0ZaMzlGODBQVTRvWWlWRCthTFdnUW1sb2s0?= =?utf-8?B?UGhsajVLM2N0YVF3QWhBU0s0WFNpREJSa0d1NmsvS2VvbjRseXRacFVZYVZw?= =?utf-8?B?VWtFbkZzRWlhSGNjMnVldlR2TkVIQndUSG8yMGRwTWNIcVN0cWhyM0RjQnpE?= =?utf-8?B?M3NNb0NvNi9IbWRJcmlub1dZa3I1K0h6RHFjMU1LWUh0Ymk3V21hOW91Rm91?= =?utf-8?B?Y2Q0V3dLYWhBUVdBS040eXg0a3RXemNwZlBpY0szK2o0VzNhT3hITHAxNUNX?= =?utf-8?Q?4hlbZKIEUcHmCVkOXc7RWjneXGA9rGHX/H8D7wgb2Pzl?= X-OriginatorOrg: suse.com X-MS-Exchange-CrossTenant-Network-Message-Id: 16608299-f5a1-4667-581d-08dab0ca469e X-MS-Exchange-CrossTenant-AuthSource: VE1PR04MB6560.eurprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Oct 2022 05:33:24.2417 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: f7a17af6-1c5c-4a36-aa8b-f5be247aa4ba X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: myo4P+61lTpClkl2BVYFjrGO/gNcvIDp839o2+rcFd4yoXCvUv20vNpDaV53LpwV6350f0TuRgRA90AfSZUj5g== X-MS-Exchange-Transport-CrossTenantHeadersStamped: AS8PR04MB7750 X-Spam-Status: No, score=-3029.8 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,NICE_REPLY_A,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_PASS,SPF_PASS,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 18.10.2022 00:23, H.J. Lu wrote: > On Sat, Oct 15, 2022 at 11:39 PM Jan Beulich wrote: >> >> On 14.10.2022 20:10, H.J. Lu wrote: >>> On Fri, Oct 14, 2022 at 2:52 AM Jan Beulich wrote: >>>> >>>> On 14.10.2022 11:12, Haochen Jiang wrote: >>>>> From: wwwhhhyyy >>>>> >>>>> x86: Support Intel AVX-IFMA >>>>> >>>>> Intel AVX IFMA instructions are marked with CpuVEX_PREFIX, which is >>>>> cleared by default. Without {vex} pseudo prefix, Intel IFMA instructions >>>>> are encoded with EVEX prefix. {vex} pseudo prefix will turn on VEX >>>>> encoding for Intel IFMA instructions. >>>> >>>> I firmly object to the proliferation of this mis-feature. As expressed >>>> before for AVX-VNNI, as long as the user has disabled AVX512 (or >>>> respective sub-features thereof), there should be no need to use {vex} in >>>> the source code. There's also no reason at all to make the disassembler >>>> print {vex} prefixes - we don't do so for any other insns (apart from >>>> AVX-VNNI) where an ambiguity exists between their VEX and EVEX encodings >>>> (when none of the EVEX-specific features is used). >>> >>> The {vex} prefix is used with AVX-IFMA instructions so that IFMA instructions >>> without a prefix, which are generated by compilers or handwritten, will be >>> always encoded with EVEX. >> >> So again: Why is this necessary when a programmer disabled AVX512? I fully >> agree we need to pick the EVEX encoding by default if available, but I see >> no reason whatsoever to insist on a {vex} prefix when the EVEX variant is >> unavailable anyway. As you said back at the time for AVX-VNNI - this was a >> design decision taken at Intel. Which is fine for a draft implementation. >> But decisions for an open source project should be taken in the open, and >> opinions of others should not simply be put off. >> > > We can discuss how to initialize i.vec_encoding. But it is orthogonal to > this patch. One can view it as orthogonal, yes, but if we change the model then doing so before more code and testcases need changing is imo preferable. Jan