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 B00A8C433FE for ; Thu, 20 Oct 2022 13:18:37 +0000 (UTC) Received: from localhost ([::1]:54368 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1olVRT-0007hH-SP for qemu-devel@archiver.kernel.org; Thu, 20 Oct 2022 09:18:36 -0400 Received: from [::1] (helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1olVGl-0002X5-29 for qemu-devel@archiver.kernel.org; Thu, 20 Oct 2022 09:07:31 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:35412) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1olTmN-0005Se-0H for qemu-devel@nongnu.org; Thu, 20 Oct 2022 07:32:11 -0400 Received: from mail-pj1-x1036.google.com ([2607:f8b0:4864:20::1036]:54955) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1olTmI-0001NK-0g for qemu-devel@nongnu.org; Thu, 20 Oct 2022 07:32:02 -0400 Received: by mail-pj1-x1036.google.com with SMTP id h14so2953459pjv.4 for ; Thu, 20 Oct 2022 04:31:55 -0700 (PDT) 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=u9Qe7Jx8nw6RSUQ5K5ELFTWQN+HxVh9NKWZmwGQCIis=; b=QeLBtBR2/ss/GK+RiBp/EMlOzBDtuYg9pz5o/6EUMqdOCTRPPVyKjXFgBCtKsILAR7 sVV1WYHchIBYvHoCCiHjxakP22EG+bNNGCO7c3/hxFNEffE4bKOP5igdjI4cgbAeVZKF 5arxX5rZIdmlgGGeuW7TibKZysoSbDXwd5AsBO4cXCjkk6l9ynNkoG442OzsEEK+AKu2 k7LL97QeYd+Z9U6JPGchc+rzWwCfBQBfIYd7Raac1gIdT9uyetETO1RB8/sJurUFHnA5 AGYYUF+4pgdTrYsvOleAgVj/D3fzThYKz4QjSur7M91EhrWmIYD2YKfkDqN7jBaZ4N0y nddQ== 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=u9Qe7Jx8nw6RSUQ5K5ELFTWQN+HxVh9NKWZmwGQCIis=; b=XI3KjVL0Iv079WOfnaigI4GCpEM7c/cBC8ehyktjCIQkj3WqUT7l5HO6z1Vtl7S3cC wghelkLz13ZVbi1z7iVhrvxC0jW1kPbHz2/QdGxHSNFB/y1X9lwRpxbXi28hIfDPiFU+ 3pGXraTzC7DQLjP+k+4xMT6sMYnrJ3nGW+ZA1m/8zxKNCqaBlzsNPBOw7OZNnerIRY3v mR8AkKeXbhaeT2G65fxrixBmUEkf4gWA7AhNuvCEyU/vGB7qKZ6xsQSNupK0Uc4a3bTf zjHbKj78xjgRzAWk6Zano8SQCHCnHNfIzIrD2oe6lbyanuFa2unJ3s4hxtShLKb8eIOp OlNg== X-Gm-Message-State: ACrzQf3FqQKfsif4SDwamMdXISWXpRm+zyeIsKcOgCPIQIC+bu+ffshD nFybynqe0Ebp4XdJGhbnaK19ZA== X-Google-Smtp-Source: AMsMyM7+SbLeLHrlgFsMSDnFVhjOcDtwPmDSMv18jTemBQLJleO0Kb2ZAUNg8xI0mjt47Da+2/WU2g== X-Received: by 2002:a17:902:db05:b0:185:537a:7440 with SMTP id m5-20020a170902db0500b00185537a7440mr13394151plx.13.1666265514297; Thu, 20 Oct 2022 04:31:54 -0700 (PDT) Received: from [192.168.1.107] ([149.135.10.35]) by smtp.gmail.com with ESMTPSA id n21-20020a63ee55000000b00439d071c110sm11510476pgk.43.2022.10.20.04.31.49 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 20 Oct 2022 04:31:53 -0700 (PDT) Message-ID: <3390d4b8-ce83-ef7a-5384-302109915eb8@linaro.org> Date: Thu, 20 Oct 2022 21:31:45 +1000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.2.2 Subject: Re: [RFC PATCH 3/3] tcg/riscv: Remove a wrong optimization for addsub2 Content-Language: en-US To: LIU Zhiwei , qemu-devel@nongnu.org, qemu-riscv@nongnu.org Cc: Alistair.Francis@wdc.com, palmer@dabbelt.com, bin.meng@windriver.com, lzw194868@alibaba-inc.com References: <20221020104154.4276-1-zhiwei_liu@linux.alibaba.com> <20221020104154.4276-4-zhiwei_liu@linux.alibaba.com> From: Richard Henderson In-Reply-To: <20221020104154.4276-4-zhiwei_liu@linux.alibaba.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=2607:f8b0:4864:20::1036; envelope-from=richard.henderson@linaro.org; helo=mail-pj1-x1036.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 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=-0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable 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" On 10/20/22 20:41, LIU Zhiwei wrote: > It's not clear what it is doing here. And it's wrong because bl and > al are both register, so we can't add them by an ADDI instruction. > > Signed-off-by: LIU Zhiwei > --- > tcg/riscv/tcg-target.c.inc | 3 --- > 1 file changed, 3 deletions(-) > > diff --git a/tcg/riscv/tcg-target.c.inc b/tcg/riscv/tcg-target.c.inc > index bfdf2bea69..a07fd0864f 100644 > --- a/tcg/riscv/tcg-target.c.inc > +++ b/tcg/riscv/tcg-target.c.inc > @@ -705,9 +705,6 @@ static void tcg_out_addsub2(TCGContext *s, > tcg_out_opc_reg(s, OPC_SLTU, TCG_REG_TMP0, > rl, al); > } > - } else if (rl == al && rl == bl) { > - tcg_out_opc_imm(s, OPC_SLTI, TCG_REG_TMP0, al, 0); > - tcg_out_opc_reg(s, opc_addi, rl, al, bl); > } else { Removing this is incorrect; it's a simple typo for opc_add. The case being required for rl == al == bl, which the following else will treat incorrectly. r~