From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-3.1 required=3.0 tests=AWL,BAYES_00,BODY_8BITS, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, T_DKIM_INVALID shortcircuit=no autolearn=ham autolearn_force=no version=3.4.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id 519BD1F954 for ; Wed, 22 Aug 2018 17:03:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727238AbeHVU2o (ORCPT ); Wed, 22 Aug 2018 16:28:44 -0400 Received: from mail-wm0-f47.google.com ([74.125.82.47]:52376 "EHLO mail-wm0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727095AbeHVU2o (ORCPT ); Wed, 22 Aug 2018 16:28:44 -0400 Received: by mail-wm0-f47.google.com with SMTP id y139-v6so2643933wmc.2 for ; Wed, 22 Aug 2018 10:03:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:references:date:in-reply-to:message-id :user-agent:mime-version:content-transfer-encoding; bh=B0p3eEqRmi2bL4q9l3vJ94DCZm0wT83AyxbWt+RnXjw=; b=lMrBOUkvO9KzKvgWVaGdy+mTsQ37i9+440ww0Oebmhre9Bu4F3Bg+lJtj9PnP6AAEz JXQI0yaCBVW6X4ZYJ6j1uGmZMWy/CMNP5zPXMxk5uqAcxjCehPyIiGzCgfnEw6aZPXsG tYsDccwzL8ItgR8kRbPiqSq6AbDraaS2AT8tUr8dmyiih8Dt2mpN0EDOgHwQJ1tDNt8x 5pn62qsx1n6MMfkJIokkz1Qya5jK2ytsmYv1qJuqpZRG/VG6vnhSBTVGsBCr3B7/DwsJ R/w9g/l04h/0nP+ujhVKaZ3B+2Dk516Cvyk6FxpyzLYEUk/LWXqP2ALE9xyHq5StZ6tp CmhQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:references:date :in-reply-to:message-id:user-agent:mime-version :content-transfer-encoding; bh=B0p3eEqRmi2bL4q9l3vJ94DCZm0wT83AyxbWt+RnXjw=; b=FybEycMBOGjSTWlEfjTHpFK5jkJeL8hQOS+xYhNnusKsw8CjMXOCMIqAwW/pu0JVWU ae1GaMem5iFfYhRiPyyS0DOkb+hk8LNFj+StUBVeFoS2mNgpSZSwXWeOZoXKKBXhx+q0 Hv/ccgMoCn7WYrgOu+QEhxMezBbmpV+UAX2vt3EjIio0t2RNjnvaYew71qP2R8zW3Jkh +eampWlfmmbJJqKewuWcOBp9WQRBVD0jfXcjGOfkuugxyL/qFT4ehbi3w6isCi2gzGKW cWlcKdps2wVtd5px1QQjrsb97A64ssSk0Bsi8FlvzGf5DYIVZNuGSWaPBWfs6cI3gVEC pSPA== X-Gm-Message-State: APzg51BU+OkHpbd6Tr6JLagnaQ4BWkliNl+/Mrm8VaX+4gS4b8MgN2t3 RzE9uCa87zwSVoj2wDLEeS4= X-Google-Smtp-Source: ANB0VdYwgB3fMkeS/Q23VnILPRoLoa0g+BNaWTPxqzF9mJxIvqhGEd/ljlJnkAibkK9VhSbRo9vsgg== X-Received: by 2002:a1c:4489:: with SMTP id r131-v6mr2756019wma.128.1534957381520; Wed, 22 Aug 2018 10:03:01 -0700 (PDT) Received: from localhost (168.50.187.35.bc.googleusercontent.com. [35.187.50.168]) by smtp.gmail.com with ESMTPSA id r140-v6sm2932431wmd.7.2018.08.22.10.03.00 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 22 Aug 2018 10:03:00 -0700 (PDT) From: Junio C Hamano To: Jeff King Cc: Derrick Stolee , Duy Nguyen , =?utf-8?B?w4Z2YXIgQXJuZmrDtnLDsA==?= Bjarmason , "brian m. carlson" , Git Mailing List Subject: Re: [ANNOUNCE] Git v2.19.0-rc0 References: <20180822030344.GA14684@sigill.intra.peff.net> <20180822053626.GB535143@genre.crustytoothpaste.net> <20180822060735.GA13195@sigill.intra.peff.net> <20180822151703.GB32630@sigill.intra.peff.net> <20180822162609.GA11904@sigill.intra.peff.net> <7ea416cf-b043-1274-e161-85a8780b8e1c@gmail.com> <20180822165923.GA14878@sigill.intra.peff.net> Date: Wed, 22 Aug 2018 10:02:59 -0700 In-Reply-To: <20180822165923.GA14878@sigill.intra.peff.net> (Jeff King's message of "Wed, 22 Aug 2018 12:59:23 -0400") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Jeff King writes: > On Wed, Aug 22, 2018 at 12:49:34PM -0400, Derrick Stolee wrote: > >> > Yes, that was what I meant. We actually did switch to that hand-rolled >> > loop, but later we went back to memcmp in 0b006014c8 (hashcmp: use >> > memcmp instead of open-coded loop, 2017-08-09). >> >> Looking at that commit, I'm surprised the old logic was just a for >> loop, instead of a word-based approach, such as the following: >> [...] >> +struct object_id_20 { >> +       uint64_t data0; >> +       uint64_t data1; >> +       uint32_t data2; >> +}; >> + >>  static inline int hashcmp(const unsigned char *sha1, const unsigned char >> *sha2) >>  { >> -       return memcmp(sha1, sha2, the_hash_algo->rawsz); >> +       if (the_hash_algo->rawsz == 20) { >> +               struct object_id_20 *obj1 = (struct object_id_20 *)sha1; >> +               struct object_id_20 *obj2 = (struct object_id_20 *)sha2; > > I wonder if you're potentially running afoul of alignment requirements > here. Yup, and I think that all was discussed in that old thread ;-)