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=-5.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, 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 C42F8C433EF for ; Wed, 22 Sep 2021 17:28:10 +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 7E34160F6E for ; Wed, 22 Sep 2021 17:28:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 7E34160F6E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=xen0n.name Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:58968 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mT62T-0003sE-Mp for qemu-devel@archiver.kernel.org; Wed, 22 Sep 2021 13:28:09 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:33530) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mT60t-0001b3-O7 for qemu-devel@nongnu.org; Wed, 22 Sep 2021 13:26:33 -0400 Received: from [115.28.160.31] (port=39790 helo=mailbox.box.xen0n.name) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mT60q-0003q5-BV for qemu-devel@nongnu.org; Wed, 22 Sep 2021 13:26:30 -0400 Received: from [192.168.9.172] (unknown [101.88.29.172]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits)) (No client certificate requested) by mailbox.box.xen0n.name (Postfix) with ESMTPSA id 32596633F2; Thu, 23 Sep 2021 01:26:23 +0800 (CST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=xen0n.name; s=mail; t=1632331583; bh=5uS/HBSfwscyyDwfYtQhSd4T4eugzKMcGMICb7mrcB0=; h=Date:Subject:To:References:From:In-Reply-To:From; b=dxcGJh7Ok7H7g0WKR/4hLlR3kTk2RjLzT/IjE7lXuB8iJT1LjoRrVhpaPwK1vhyql EYaQnR7EClg0j0TmgC34DP6tqVau2k7Cl2njnMR2zbPCl2GOvY8g+8S70I5iSbKN+s /5v7E47NDWNbCDqei7Z87XG3V8ASFnfDnyk3Gfa8= Message-ID: <22edcd8f-9299-2d7c-9cb9-973381b9c83c@xen0n.name> Date: Thu, 23 Sep 2021 01:26:22 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:94.0) Gecko/20100101 Thunderbird/94.0a1 Subject: Re: [PATCH v2 20/30] tcg/loongarch64: Implement setcond ops Content-Language: en-US To: Richard Henderson , qemu-devel@nongnu.org References: <20210921201915.601245-1-git@xen0n.name> <20210921201915.601245-21-git@xen0n.name> <596cef66-7b19-1ef8-92ec-1e916711b737@linaro.org> From: WANG Xuerui In-Reply-To: <596cef66-7b19-1ef8-92ec-1e916711b737@linaro.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Host-Lookup-Failed: Reverse DNS lookup failed for 115.28.160.31 (failed) Received-SPF: pass client-ip=115.28.160.31; envelope-from=i.qemu@xen0n.name; helo=mailbox.box.xen0n.name X-Spam_score_int: -12 X-Spam_score: -1.3 X-Spam_bar: - X-Spam_report: (-1.3 / 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, RDNS_NONE=0.793, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Hi Richard, On 9/22/21 23:13, Richard Henderson wrote: > On 9/21/21 1:19 PM, WANG Xuerui wrote: >> +static void tcg_out_setcond(TCGContext *s, TCGCond cond, TCGReg ret, >> +                            TCGReg arg1, TCGReg arg2, bool c1, bool c2) >> +{ >> +    TCGReg tmp; >> + >> +    if (c1) { >> +        tcg_debug_assert(arg1 == 0); >> +    } >> +    if (c2) { >> +        tcg_debug_assert(arg2 == 0); >> +    } > > You don't need to work quite this hard.  Only the second argument will > be constant.  If both are constant, we will have folded the operation > away.  If the first argument was constant, we will swap the condition. Thanks for the clarification; again something I didn't discover during my (often cursory) read of tcg middle-end code. I'll drop all the c1 thing in v3.