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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 04880C43217 for ; Thu, 1 Dec 2022 20:34:41 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1p0qGC-0007tJ-Vv; Thu, 01 Dec 2022 15:34:21 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1p0qGB-0007sn-HT for qemu-devel@nongnu.org; Thu, 01 Dec 2022 15:34:19 -0500 Received: from mail-pf1-x432.google.com ([2607:f8b0:4864:20::432]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1p0qG9-0003cC-AX for qemu-devel@nongnu.org; Thu, 01 Dec 2022 15:34:19 -0500 Received: by mail-pf1-x432.google.com with SMTP id 124so3033908pfy.0 for ; Thu, 01 Dec 2022 12:34:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; 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=C41hdrvmJzWT4QWltLxdv6w04gTtATgDK19BXleL3nY=; b=jE2hX3TGvU4QMDzCz08R6SAJ/Wj8pWneVPoYXQuIpzHDRZCCgwGP00Q+qAZrp8R61s ELxm3AZhgq6KiyP0vZRSboiIer1frjVifE5pXBPGmnwN2R0mEesjwYczPUIUggcjnh0m 2bzfq/r+of56n87ooDQfyDj6StOiY0f76Q8j5xZ31GQzRHTSVZ7bMFi84yz2ydScNpLs knN5pxiNtGew1nx/pL7aN2ASJCeI2AOYwoUS1vwc7wOAe/5kDC4Bxxy3V51AXBy0drUt p10vV5DWYxpwQaHBppq38UqV/KGByGI/1Gsd13xRkS1jBDN4zdiHQ0qJ4b/wBmU95igm JWXw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; 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=C41hdrvmJzWT4QWltLxdv6w04gTtATgDK19BXleL3nY=; b=ImV3aFEPGtPaWgNhHSbgWTLGQDjrDLhxaa04fPlkyIOFIAh62eHERl2UFegyl+8Om1 8AtJ5RDVTICUAFkOwAvZHKPW7UkT2Rh0mDDR14ff085L0W8BXK8obPqw9DSOfXPL4RHn mM7JQW2P3VphW89ZplQi1xPLgsGrHO7l4VgrQNmDHQ2g1/GYhYCu8ZeFyiOceG/kOpkO eyo0gTbhx+13TJ2A0TvfL1pHA7yg0M3v5dr4ViHv4SyA82jawhu4tjS2Sf7aR1f3CZMz NaRnde3/JyUbfjpSfLRcqH8Q14u5BD4BbD5LQqeR4lOQTYsooRExcBCXMTAohjNmWGhf UTog== X-Gm-Message-State: ANoB5plA7ev7vrxuNKjGcpzAZnkNN4YU4ZEYr6STt8eoOdqRD3smLCIm 6SB2C43An5UznDTyiVus0WRO7w== X-Google-Smtp-Source: AA0mqf798EYaTJrE5IBz325b2hdN5zBrheEWiwGto9t404/wyBmI+s7sYIcfynVI5HBFLSUNvKqTng== X-Received: by 2002:a63:4605:0:b0:478:80f8:66a6 with SMTP id t5-20020a634605000000b0047880f866a6mr1411098pga.222.1669926855204; Thu, 01 Dec 2022 12:34:15 -0800 (PST) Received: from ?IPV6:2602:47:d48a:1201:e3cc:2e37:17d4:f1d5? ([2602:47:d48a:1201:e3cc:2e37:17d4:f1d5]) by smtp.gmail.com with ESMTPSA id nt15-20020a17090b248f00b00217090ece49sm3419938pjb.31.2022.12.01.12.34.14 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 01 Dec 2022 12:34:14 -0800 (PST) Message-ID: Date: Thu, 1 Dec 2022 12:34:12 -0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.2 Subject: Re: [PATCH 24/26] tcg: Introduce tcg_temp_ebb_new_* Content-Language: en-US To: =?UTF-8?Q?Alex_Benn=c3=a9e?= Cc: Ilya Leoshkevich , qemu-s390x@nongnu.org, qemu-devel@nongnu.org References: <20221006034421.1179141-1-richard.henderson@linaro.org> <20221006034421.1179141-25-richard.henderson@linaro.org> <20221130180703.dprt7lzmppgfihtp@heavy> <5f8d64c4-3ad0-2340-6fe0-86707b41980b@linaro.org> <87mt87aqc5.fsf@linaro.org> From: Richard Henderson In-Reply-To: <87mt87aqc5.fsf@linaro.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2607:f8b0:4864:20::432; envelope-from=richard.henderson@linaro.org; helo=mail-pf1-x432.google.com X-Spam_score_int: -23 X-Spam_score: -2.4 X-Spam_bar: -- X-Spam_report: (-2.4 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.257, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 12/1/22 11:13, Alex Bennée wrote: >> I'm not sure I want to take this anymore. It's confusing to use. I >> really think what I should do instead is improve the TCG register >> allocator. > > Whats the ultimate aim for the rewrite? Hold values in target registers > over the extended block? What about avoid spills between potential fault > points? Primary goal is to handle register allocation across basic blocks without front end translators needing to consider "local" vs "temporary". Which would also allow any use of branches in the middle-end, where we currently have to worry about accidentally killing temporaries held by the front end. That's where this patch fails, in that it makes the current situation even more complicated. Secondary goal would be proper register allocation across basic blocks. Tertiary goal would be single-assignment form, to allow better optimizations. I'll have to do some research before committing to do anything in this area. r~