From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-x530.google.com (mail-pg1-x530.google.com [IPv6:2607:f8b0:4864:20::530]) by sourceware.org (Postfix) with ESMTPS id B79E63858D35; Sun, 30 Apr 2023 16:37:31 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org B79E63858D35 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-pg1-x530.google.com with SMTP id 41be03b00d2f7-5191796a483so1096651a12.0; Sun, 30 Apr 2023 09:37:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1682872650; x=1685464650; 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=cVcPBEpcJ1co1P3hHfuReoDcNuJwGQfCP7VwI97MGgk=; b=VJEp0XNWHsfVGTqCx543lhv+ydtERFG7qXxq+6GsQRZt9c4rbiRX5vO6NKlSciNDbb 4IXMp9Ii9+i9umhQRGx3PBI+Metns3I1lire8RZI3/d98w77m0IIvokcZUEhWx6uJe9y xk7IPaXdAClxceEFX3924VA3Fd4/xprJFeMU5dOLUbAJnu66Eutv+Sv6BUg9fXy8PY8Q GAFFwi+xbUaf2eJt23kiLkhK/L38BzNA5N+8iJImmw6CNGjQ+IRQHG/gK/TRxFpN0jQt PVmacSEB8NeFqnm2Vb9ZWZINUVEufmP7/OpjxfbfEBJaeBWCJ0ZdNkR9BkLwiSnlRrnu bbdQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1682872650; x=1685464650; 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=cVcPBEpcJ1co1P3hHfuReoDcNuJwGQfCP7VwI97MGgk=; b=AXnzg7PWx76NFjTYK2DUmBoPAS2EKFaT+wl9CbcVOvn9fw8tVBVrnlGcFWZp2U7kT5 RynzQ2SAuKD4Et+MActcFxngIqXyKDeW4odo/hM0Csc+t6UL9dDRisjvRgxJWX4JW6z8 YZ2jLQFqLIruPC6dJHKNWGqTWrAgdeaRWFkCjVBd4JZam5GP1suwKM1HFH4PsIAsK6Bl YCJIJatm3fIqK7ZU92thFQNWxE/FwhojEcNMLF8cMf31sAsMxp5SABP45wC6kpvsiXNM haJeElSTRsuMze+T7dVzEkXXKqI4byJijqJ85tsKoC3Sb31lHiLGi734DCba7apuW+5N meFw== X-Gm-Message-State: AC+VfDyOCfjc2JO2ZVN6DRgPsMm8qCoGbrCiQAt7sJjVaCo0F7maTXZ6 cq3cz+NOIfL48kGp9nfNl2s= X-Google-Smtp-Source: ACHHUZ5IUBc5ONBkcdUN7Z2mtUj52JzZFhXN7bKncUuFv/oVCa6ynzmiEUNqNwuMAhUXsJgRXjFLPA== X-Received: by 2002:a17:902:7c85:b0:1a6:46f2:4365 with SMTP id y5-20020a1709027c8500b001a646f24365mr10904017pll.30.1682872650495; Sun, 30 Apr 2023 09:37:30 -0700 (PDT) Received: from ?IPV6:2601:681:8600:13d0::99f? ([2601:681:8600:13d0::99f]) by smtp.gmail.com with ESMTPSA id p18-20020a170902ead200b001aaf919c178sm152941pld.250.2023.04.30.09.37.29 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 30 Apr 2023 09:37:29 -0700 (PDT) Message-ID: <9eab1572-f1e5-c4a8-3460-259f71d77c96@gmail.com> Date: Sun, 30 Apr 2023 10:37:28 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.9.1 Subject: Re: [PATCH v5 00/11] RISC-V: Implement ISA Manual Table A.6 Mappings Content-Language: en-US To: Hans Boehm , Patrick O'Neill Cc: Palmer Dabbelt , gcc-patches@gcc.gnu.org, gnu-toolchain@rivosinc.com, Vineet Gupta , Andrew Waterman , kito.cheng@sifive.com, Daniel Lustig , cmuellner@gcc.gnu.org, Andrea Parri References: <20873714-5809-0be2-35f0-91b76b80d7e5@rivosinc.com> From: Jeff Law In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-3.3 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM,NICE_REPLY_A,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 4/28/23 12:45, Hans Boehm wrote: > We're certainly pushing for the same ABI (A.6 + trailing fence on store) > in LLVM as well. I'm about to upload a pull request for the psABI > document that describes this version of the ABI, and a bit of the > rationale for it. I'll attach the current draft here. > > I agree that compatibility is critical here, not just across llvm and > gcc, but also with other language implementations. That's part of the > reason to get this correct asap. > > I believe that standardizing on A.6 + trailing fence on store, though > initially suboptimal, is by far the best bet to get us to an efficient > ABI in the long term. I expect the A.7 ABI to perform well. A.6, even > without the trailing store fence, has annoyingly expensive seq_cst > loads, which I would really like to get away from. Thanks for the additional info. This stuff is well outside my area of expertise, so having someone with your background to give key insights is definitely appreciated. jeff