From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pj1-x102c.google.com (mail-pj1-x102c.google.com [IPv6:2607:f8b0:4864:20::102c]) by sourceware.org (Postfix) with ESMTPS id C6EBE3858CDB for ; Thu, 25 Jan 2024 00:07:32 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org C6EBE3858CDB Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=rivosinc.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=rivosinc.com ARC-Filter: OpenARC Filter v1.0.0 sourceware.org C6EBE3858CDB Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=2607:f8b0:4864:20::102c ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1706141255; cv=none; b=s8UvtX77+opELqsw9sBLR9dl3RCDNY6lE+LVgWuLJuq8keSajuJzfo8aQfro9hi58moc2p2+pK/xlobOsnyZWmiX9khsxgtDHZitLxUMnFUqPL+aB+Bm/+Ws2M9vtGbms4h7jtuGq4SasmQmz23yIes477zAmjZgeqaKwym/8UQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1706141255; c=relaxed/simple; bh=0BzTFJ21+XwtnYzYY3QmwNiM4r2ct78hI+OK91RdTfw=; h=DKIM-Signature:Message-ID:Date:MIME-Version:Subject:To:From; b=WGG97Uu3jaCuiNw/nyCKcTLE42Iru0I3qzVi96qtWI3tAYddB4V0CaQABYrnjvdZNhooOCbzs8YdnoB6gD/cgRZM8kKPl/i7WdHBDLl6g8vtloqV7v2UsOqQ1mTuaD1NfA0Yx9TVkw8AzfjO38H7FGPIxQRryGhJVM5hlOy28Xg= ARC-Authentication-Results: i=1; server2.sourceware.org Received: by mail-pj1-x102c.google.com with SMTP id 98e67ed59e1d1-29065efa06fso3696934a91.1 for ; Wed, 24 Jan 2024 16:07:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rivosinc-com.20230601.gappssmtp.com; s=20230601; t=1706141252; x=1706746052; darn=gcc.gnu.org; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=D5Xvvtn1q3v63U10tNeNDK9az0I9/4pv4jtXqenyG0E=; b=m4I7tzgif1SCT1ynhVapkC/ZjrUq39fuwgx1TAZF435PPg/uBDaxFc5zi2a8c4vx3Y Q2rW8KEKFHkBpguE88g5Bf8e5ulcnVvsGcP9PPWUTt0lO6k8AjsdcttT4v60vjezx6Fa yArhj6bExBnW1qpomtiMuFGJDd9tl+oe4F0VR9WTyXoE8rldjVXI5dqOi4DW2KFEyLgs 7ccLp650EEHNT4qLYiHZqouWKTAkSQFLy05FcrzLLg4JGO15tvul7/41uovMfV4PAPed wi66EPx7Hls9o1cbcQxPznJBAwPOD5ivVGNsVd0Hgr+vD7krlFEwEoDPlhCW642ucoxR iBvQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1706141252; x=1706746052; h=content-transfer-encoding:in-reply-to:from:references:cc: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=D5Xvvtn1q3v63U10tNeNDK9az0I9/4pv4jtXqenyG0E=; b=oMG/LZqv1thQ9tSYYCLaiinnZLTbT/MvJZ/v6B2tuoarr+dQncWQGhKRSEv5VC0R8M nnOPeOJf60EyaDQJqa0iFeQj1k1na1ge0PgxiHVK+w8wL5V1c21SfK4at5oATHXxAF/m 4zST1Tx6tyMSMJYWqZAgyR5QhG57DrAT8s1QwYYu3RgEVjrwM3WVLys4FrJ/547AsL9A 3ny74/XtuV4Z5x695Dnf4BI/1HyTL3JVi7i5q07GHu5pnPM1yWd0SPywZApZrgC/laNq hpydwGWX+dA0rNd73oHQrNjMkIQB3qYdgJelK+Ax6peags0nwLJzaluIoq5Q8LPUwo8W 7A/Q== X-Gm-Message-State: AOJu0YwyoV7XbLxpgsXz7CYrr0q0PEZpeqckv6YYdLfzK58nGB9wkXiP FwILiSyute00UPJVspR1pt/uHULfJjTFg7KFyn//YsYPmXt6AWudkb1x0Ibxovw= X-Google-Smtp-Source: AGHT+IEIXAU3vofXTz5QJkTrypR9Ufzkikmj+n3Yg23Vme6FINgTaFcGqvfHhnBbkvcOmtXz0FVmiA== X-Received: by 2002:a17:90a:d486:b0:28e:7b57:d219 with SMTP id s6-20020a17090ad48600b0028e7b57d219mr128292pju.92.1706141251741; Wed, 24 Jan 2024 16:07:31 -0800 (PST) Received: from [10.0.17.156] ([12.44.203.122]) by smtp.gmail.com with ESMTPSA id kn4-20020a170903078400b001d4bb7cdc11sm2529043plb.88.2024.01.24.16.07.30 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 24 Jan 2024 16:07:31 -0800 (PST) Message-ID: <98548046-4e2a-4eaa-adab-1692445726cd@rivosinc.com> Date: Wed, 24 Jan 2024 16:07:30 -0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] RISC-V: Don't make Ztso imply A Content-Language: en-US To: Jeff Law Cc: Palmer Dabbelt , gcc-patches@gcc.gnu.org, Andrew Waterman References: <20231213035405.2118-1-palmer@rivosinc.com> From: Patrick O'Neill In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-4.1 required=5.0 tests=BAYES_00,BODY_8BITS,DKIM_SIGNED,DKIM_VALID,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 12/16/23 10:58, Jeff Law wrote: > > > On 12/15/23 17:14, Andrew Waterman wrote: >> On Fri, Dec 15, 2023 at 1:38 PM Jeff Law wrote: >>> >>> >>> >>> 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. >> >> Palmer is correct.  There is no coupling between Ztso and A. (And >> there are uncontrived examples of such systems: e.g. embedded >> processors without caches that don't support the LR/SC instructions, >> but happen to be TSO.) > Thanks for the confirmation.  Palmer, commit whenever is convenient > for you. > > jeff I was going to commit on behalf of Palmer and saw this was marked as Deferred in patchworks: https://patchwork.sourceware.org/project/gcc/patch/20231213035405.2118-1-palmer@rivosinc.com/ Is this an old marking from before Andrew confirmed that they are independent? Thanks, Patrick