From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F2812C352AA for ; Wed, 2 Oct 2019 15:23:30 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id BE02421848 for ; Wed, 2 Oct 2019 15:23:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="q423oyDi" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BE02421848 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:56578 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iFgTR-0005qs-Uh for qemu-devel@archiver.kernel.org; Wed, 02 Oct 2019 11:23:29 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:47791) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iFgN6-0000K8-7d for qemu-devel@nongnu.org; Wed, 02 Oct 2019 11:16:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iFgN4-0007U1-H9 for qemu-devel@nongnu.org; Wed, 02 Oct 2019 11:16:55 -0400 Received: from mail-pl1-x643.google.com ([2607:f8b0:4864:20::643]:42130) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1iFgN3-0007Rj-JS for qemu-devel@nongnu.org; Wed, 02 Oct 2019 11:16:53 -0400 Received: by mail-pl1-x643.google.com with SMTP id e5so7169563pls.9 for ; Wed, 02 Oct 2019 08:16:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=subject:to:cc:references:from:openpgp:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=05tls94euaalL4DwohLqpfyv0VHo5flj8PcM2IO60Ik=; b=q423oyDiT1KR2aho2xzaMLiIjYNyGqCROKCvVRItQ7JOG4MqK3YU/jUoxyBJp70onE k2qvpCR4Kr5saIB4hratTKb26cl9ycVpxQiLpR3lFzSoR0M3hBjN87aev4+jMRtUX86z nDtPvAeugJd+7FsL81O+iFXObZHRtrTe3uWW/yXJZ25TQ1k4nWiXSeWs/o1zisoUqhcG fZWe18a+jZf+jePdWFaCDpnd0x99WxW59WDgUpWMry6vDbpsaeIflCMY+FeRNIYqPLzw 3uCvsPY7qiQtt4ygHCjCnzmer8Kx8SZkZQlm/zULkDbc2HNCsokgd+MsPjZZA0jFlYv+ GXqg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:openpgp:message-id :date:user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=05tls94euaalL4DwohLqpfyv0VHo5flj8PcM2IO60Ik=; b=pIaE6nglP/NYTVbQWuxPMHkKiqpakp/i+mQXa006yWeLhLG6NH1MRutFUBmyzpQ+88 pVaTV1eVLOeNGM3b5Qi39Ani1xDpK7eekdY8u+kX0zscGzB8W7yoFyZYyJRyA//EbtsU RYbIwLTUWOz0lyXKbGV6emRNhyZ+hOZ/JgpoXrYY8l3+U/Jovv/3f0TxAvgd5zuaIVtN bDpUtfiUaU0l7EAnNkMymJleZtVYGZ5IaFW6g9JtPRi+28xGTqCceF71DfsLltUpY5Bi SiQ71CMVUkHx+YlvDlWdZ11D2r/iG27uWcWkoQ5XJ2gZY59PVypHlLMD6/zbBz9Pyxlb HnSg== X-Gm-Message-State: APjAAAWspgc8OPCrZLH3qwvirH9YvqTOaq1gmrHoVNlMO7puEc3t+eif tHWQ64LJG3j3t8x7u31BK6cGTg== X-Google-Smtp-Source: APXvYqyzthjqsqkvxmm+IrtXCYCzcpPeP8xDiW+fZlh1RnHyiaYN8gIuom3PwnMnad2t8X20LSvxxw== X-Received: by 2002:a17:902:326:: with SMTP id 35mr4352618pld.128.1570029408349; Wed, 02 Oct 2019 08:16:48 -0700 (PDT) Received: from [192.168.1.11] (97-113-7-119.tukw.qwest.net. [97.113.7.119]) by smtp.gmail.com with ESMTPSA id s17sm30893669pgg.77.2019.10.02.08.16.46 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 02 Oct 2019 08:16:47 -0700 (PDT) Subject: Re: [RFC PATCH] configure: deprecate 32 bit build hosts To: =?UTF-8?Q?Daniel_P=2e_Berrang=c3=a9?= References: <20190925233013.6449-1-alex.bennee@linaro.org> <4512b61a-ed82-e628-88e5-f44ef87c2b50@linaro.org> <20190930092519.GB11996@redhat.com> <87impakrky.fsf@linaro.org> <58da7aa4-877b-2c85-71f5-e703a841e6d4@linaro.org> <20191002091037.GB607@redhat.com> From: Richard Henderson Openpgp: preference=signencrypt Message-ID: <02ab8cdf-1011-2bbb-c720-731c2b68537e@linaro.org> Date: Wed, 2 Oct 2019 08:16:45 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20191002091037.GB607@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2607:f8b0:4864:20::643 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , "open list:RISC-V" , Mark Cave-Ayland , QEMU Developers , "qemu-discuss@nongnu.org" , qemu-s390x , "qemu-arm@nongnu.org" , qemu-ppc , =?UTF-8?Q?Alex_Benn=c3=a9e?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 10/2/19 2:10 AM, Daniel P. Berrangé wrote: >> GCC only implements int128_t for 64-bit targets. > > QEMU probes for that during configure and sets CONFIG_INT128 > > If I'm reading correctly include/qemu/int128.h then provides a > fallback type based on a struct with two int64s. > > This has some inconvenience though as you have to use the the (inline) > function calls for all the basic operands and will be less efficient > when using the fallback. > > Presumably this is not viable for TCG ? A structure (for some ABIs) may be passed and returned by invisible reference. It's not impossible (nothing's impossible), but it adds previously unnecessary complexity to allocate that storage on the jit stack. Actually manipulating one 128-bit value consumes 4/6 of the i386 registers, which I can well imagine could wind up causing problems. Certainly manipulating two values at once is out of the question. That's less of a problem for arm and mips. Anyway, all of the pain points go away if we assume 64-bit. r~