From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org [79.124.17.100]) by master.gitmailbox.com (Postfix) with ESMTP id B4A6E43C79 for ; Wed, 27 Jul 2022 20:42:15 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id A989868B935; Wed, 27 Jul 2022 23:42:12 +0300 (EEST) Received: from mail-lj1-f175.google.com (mail-lj1-f175.google.com [209.85.208.175]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id C647468B6EA for ; Wed, 27 Jul 2022 23:42:06 +0300 (EEST) Received: by mail-lj1-f175.google.com with SMTP id b21so14046814ljk.8 for ; Wed, 27 Jul 2022 13:42:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :content-transfer-encoding; bh=McnkF0X7R1Ae60LND+8VDY72P5Eq4LgbKHGM2XXVwXc=; b=ixiAN7e/sUyTQ95hcbOqot76pxov1VcNJ0LnX38Ed2Dr5Y+7+YEKpTrN/CRIGGRlSh yZsC6vxoEv+6N4GTzDLXyHx8m+JsLDCtMQiOgzLpbXaZuDbuuRMNtizkCX4JjdwOCfoA o0AnE98JoNmWAa0oRjHgjPABbguOSAHml1pVWNFf/k7ZwzTIiW2kO0ZhK05lUCSPrh7a wyl+FiIszDCZiprnKPaEs9vQJGKxjuILLqa32x4aBHldBKvU8hHsDJfscAiC4qjMZd5O qN2LIIyTlvmp3IxtIGD+WV9tY9DEXQG+ugE+rNFrtIl5iYne8Hg2Dq41KzvkoXMulGah RWpQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:content-transfer-encoding; bh=McnkF0X7R1Ae60LND+8VDY72P5Eq4LgbKHGM2XXVwXc=; b=ELV2MWJJIz+RROFyekyQuiyvsTEpcRRK84i1BCtRIoJthxkj+4JdzkxJ7KQhpYPXnu E4JwCJ5PMyrqz77ylj0v+6WxR9t57bNZljYczdh8ATMcwGkYtaAFqf8UscyLnvQXNNsx KJeuf4ofSezxhKtNn5XV3bLAa+Oldt8b+80HmlArrjAiNN5KxaItKfR6Ljbov/VorLH8 ZNlWFnGhlmsa7tiZrwej5J0xeJF8Uk0jLgpVY6Io412KJ9pbGPhHj261Ee6Iymg+czz4 AKAnSMquUmJ74MiE8iGqVPRH2lPFIUxic9P6vSD9ETyQCHHxkaFdrB/5Z1O+bRbtVqH8 Cmlw== X-Gm-Message-State: AJIora82eU4rKJ2B4n2SSy4nkXPIGQa4WWUytBINj1G1wiRbUacOva7N spUnJOMuc6ZEf8KlBYlEwZoF+u2nxgtIaLNJUJ3HrxljLFI= X-Google-Smtp-Source: AGRyM1vLXOSa7/4QiElPWcOf3bA/3mXvtDP5/IJBZE0YKdsccAwchl2YR+x7ZebV9JKyiODHV/1VdwD/vlHM8TMRMUE= X-Received: by 2002:a2e:a78c:0:b0:25e:8a8:6d39 with SMTP id c12-20020a2ea78c000000b0025e08a86d39mr5797288ljf.44.1658954524875; Wed, 27 Jul 2022 13:42:04 -0700 (PDT) MIME-Version: 1.0 References: <05a46152f1b2458ea326edd9cfb6d817@amazon.com> In-Reply-To: From: Hendrik Leppkes Date: Wed, 27 Jul 2022 22:41:51 +0200 Message-ID: To: FFmpeg development discussions and patches Subject: Re: [FFmpeg-devel] [PATCH] enable auto vectorization for gcc 7 and higher X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: FFmpeg development discussions and patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: FFmpeg development discussions and patches Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: On Wed, Jul 27, 2022 at 7:39 PM James Almer wrote: > > On 7/27/2022 2:34 PM, Swinney, Jonathan wrote: > > I recognize that this patch is going to be somewhat controversial. I'm submitting it mostly to see what the opinions are and evaluate options. I am working on improving performance for aarch64. On that architecture, there are fewer hand written assembly implementations of hot functions than there are for x86_64 and allowing gcc to auto-vectorize yields noticeable improvements. > > > > Gcc vectorization has improved recently and it hasn't been evaluated on the mailing list for a few years. This is the latest discussion I found in my searches: http://ffmpeg.org/pipermail/ffmpeg-devel/2016-May/193977.html > > Every time this was done, it was inevitably reverted after complains and > crash reports started piling up because gcc can't really handle all the > inline code our codebase has, among other things. > No need to wait for issues, I just tested, and the same issues still persist that have existed for years with GCC now. They don't seem to care to make it compatible with inline asm, which might be fair enough, but it means it just can't work here. In file included from libavcodec/cabac_functions.h:49, from libavcodec/h264_cabac.c:36: libavcodec/h264_cabac.c: In function 'ff_h264_decode_mb_cabac': libavcodec/x86/cabac.h:199:5: error: 'asm' operand has impossible constraints GCC 11.3, configure --cpu=haswell, mingw32 So this is a NACK. It just flat out breaks builds. - Hendrik _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".