From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io1-xd33.google.com (mail-io1-xd33.google.com [IPv6:2607:f8b0:4864:20::d33]) by sourceware.org (Postfix) with ESMTPS id 8E01738582BD for ; Fri, 15 Dec 2023 21:37:47 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 8E01738582BD Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=gmail.com ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 8E01738582BD Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=2607:f8b0:4864:20::d33 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1702676268; cv=none; b=E2kPpiatiT7gHpaPyeTwy0PxvsoWwL+iATtKi53BC2+gdqRCpq0AolB8SS7lW6g4XMK7sbDKHilb9PLg9nj6ALKxQEF9yIP08Eh6XvqggrUkazsreH2rPVm5N/v7PIEBR9+4GLloUB3lTb7mbhGRJPGgCEcKAOEmTqqXBivrw48= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1702676268; c=relaxed/simple; bh=WwC80+OPjOQ5MS5iU8JOnSmh95J+UwgRXXvk37A5oQA=; h=DKIM-Signature:Message-ID:Date:MIME-Version:Subject:To:From; b=YvDSND0rsBrGeNRJZ6sVqHF0Hd7QQU2jAY+pKOeGPCCcC6aDedKzUxGP6NezqGRcYM7B+Xn7evjP0vMbM5zu/dB79p+Lt/C4Z2pXzdJEDPgIaZyjwI4Y+oT5Baet72KKba3rJx8BWXwJaeHv5TP/bhzfmyegci+/jIzZOe0KR3Q= ARC-Authentication-Results: i=1; server2.sourceware.org Received: by mail-io1-xd33.google.com with SMTP id ca18e2360f4ac-7b7020f03c9so45171639f.3 for ; Fri, 15 Dec 2023 13:37:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1702676267; x=1703281067; darn=gcc.gnu.org; h=content-transfer-encoding:in-reply-to:from:references:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=r2eQ4J5Q+1ymbG9tV6VjYqqFfrmXIMhoCB9qIZY3mQg=; b=BGyA6ZWvSiOqsyv2dTyZbHEUzMJE+oqx6u5vcvthUxcNKR5p+FBP0mCX+6lgy6B+uH t9cVatvPfeJAn0HK9V6If+6baqiG8VpdAHJIai88FHpyhf4OHdW8MLGvEhF/zP8YBqlc 5E4Kn7IDTw82ssz3dtMAFek3ybYqzDaqWA4bkkCyWemmOzXOJIZB6f3RJwLZiTrJoekw rIhg3ZOeSPGlEhg8peM3+k21U2PHzu+jUzcEBaMLfBNRXX3+CnMdsGX6LKmZZSlsdYy3 F26pcSdVOjV4VsADUcJExVLPztXCd84xx8Qr1Wqf7ySufxK6PDe1r4XFXuLIG5bS133t EhjQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702676267; x=1703281067; h=content-transfer-encoding:in-reply-to:from:references:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=r2eQ4J5Q+1ymbG9tV6VjYqqFfrmXIMhoCB9qIZY3mQg=; b=a++J4eOdmnI53lqnzM6LaV2jBc7T18Sp5BjuI6BeM5HWX4fIm6LR07HwoEAp5qiAZR qe+fOXca6FdMs5Qse7HEb648+tSQ18Bm/cwicFMDyGKTLtdmOvSHf9qZMvGM75AaziXG L41gbRgazE7ASkBR71usj4u+9YCXg7t2Gt8A6MgUV82umM4qV4mskHmcudLXRGNXGp3h aDITyIs8DhTWmwAZkQLQIEU6kQDvk0s3WE6kCffeGUXyRUr2nPfkOWPBWyuSaaMgE98G 5aH/CoQpIDSayIjwqyk5/iw0tvORLgNpWvDKbgzm9aJPXmLR7m9RUQPUqMu44J+TX3tN QecQ== X-Gm-Message-State: AOJu0YyiK2mYRw92QBe9yJWHwIovl4BqDOjZpYwAFGkmbya2Us7qFHII PFkCelL3l41Gd5nXVePwqgh52PALdwU= X-Google-Smtp-Source: AGHT+IGriyW/wVdDSZfOp4+jIgLCtfF83ktNrOc0poY5EaYHK2xFJlB8X3QXZ9s+bShneUgiB1r2yw== X-Received: by 2002:a05:6602:420f:b0:7b7:a9fa:55ec with SMTP id cb15-20020a056602420f00b007b7a9fa55ecmr1492491iob.10.1702676266667; Fri, 15 Dec 2023 13:37:46 -0800 (PST) Received: from [172.31.0.109] ([136.36.72.243]) by smtp.gmail.com with ESMTPSA id b23-20020a6b6717000000b007b6f3438062sm4796473ioc.46.2023.12.15.13.37.45 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 15 Dec 2023 13:37:46 -0800 (PST) Message-ID: Date: Fri, 15 Dec 2023 14:37:44 -0700 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] RISC-V: Don't make Ztso imply A Content-Language: en-US To: Palmer Dabbelt , gcc-patches@gcc.gnu.org References: <20231213035405.2118-1-palmer@rivosinc.com> From: Jeff Law In-Reply-To: <20231213035405.2118-1-palmer@rivosinc.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-2.4 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS,TXREP,T_SCC_BODY_TEXT_LINE 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 12/12/23 20:54, Palmer Dabbelt wrote: > I can't actually find anything in the ISA manual that makes Ztso imply > A. In theory the memory ordering is just a different thing that the set > of availiable instructions (ie, Ztso without A would still imply TSO for > loads and stores). It also seems like a configuration that could be > sane to build: without A it's all but impossible to write any meaningful > multi-core code, and TSO is really cheap for a single core. > > That said, I think it's kind of reasonable to provide A to users asking > for Ztso. So maybe even if this was a mistake it's the right thing to > do? > > gcc/ChangeLog: > > * common/config/riscv/riscv-common.cc (riscv_implied_info): > Remove {"ztso", "a"}. I'd tend to think step #1 is to determine what the ISA intent is, meaning engagement with RVI. We've got time for that engagement and to adjust based on the result. So I'd tend to defer until we know if Ztso should imply A or not. jeff