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=-5.3 required=3.0 tests=BAYES_00, 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 21143C433ED for ; Wed, 5 May 2021 17:22:08 +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 8DBCA61059 for ; Wed, 5 May 2021 17:22:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8DBCA61059 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=vivier.eu Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:52778 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1leLDp-0000a6-Qc for qemu-devel@archiver.kernel.org; Wed, 05 May 2021 13:22:06 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:41402) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1leKcf-000847-4Q for qemu-devel@nongnu.org; Wed, 05 May 2021 12:43:41 -0400 Received: from mout.kundenserver.de ([217.72.192.74]:35837) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1leKcd-0003A4-3I for qemu-devel@nongnu.org; Wed, 05 May 2021 12:43:40 -0400 Received: from [192.168.100.1] ([82.142.20.222]) by mrelayeu.kundenserver.de (mreue108 [213.165.67.119]) with ESMTPSA (Nemesis) id 1MUXh8-1m4hBu2mmG-00QVWi; Wed, 05 May 2021 18:43:26 +0200 To: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= , qemu-devel@nongnu.org References: <20210505160344.1394843-1-f4bug@amsat.org> From: Laurent Vivier Subject: Re: [PATCH] target/m68k: Remove unused variable in ABCD/SBCD memory opcodes Message-ID: <4c67e219-8698-5855-909b-21fb1c45a385@vivier.eu> Date: Wed, 5 May 2021 18:43:25 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <20210505160344.1394843-1-f4bug@amsat.org> Content-Type: text/plain; charset=utf-8 Content-Language: fr Content-Transfer-Encoding: 8bit X-Provags-ID: V03:K1:/oqEoFhmbWMbNcZYDwPVkpAmG8nCs/1ScsMRS9f0/gTxx8wzBrz yRcAJlJ+92jmyO3RzxAjXeFQd1sJtXLFgywmwLdBF9TDost9imz0O4ZbBLVyALjUIFaOk+p Oxiol2nQX8WuKRomMzBqfhFcQarL7734rvfPZVM61rAkD3GZkVSy/UAL3Qzol7njXai8Trl uaIijJRkDBm/KiYZuePig== X-UI-Out-Filterresults: notjunk:1;V03:K0:47w0lN4I0YI=:HoMBm1uY7EWiLkQrOLvcMh fRsaKP6gPxAic7TKuIc5xJ6lx2UG9dmpsothkpqj0veKE2saFwcCmfzd42rmAnQhSSmID6t/x cdUosjNtFDpqoAW68Fmn90qEWd9J9+pKuZjEgZ5m4AyfmGd6Q2O2ajb7aFGdTIgrXrWJx347e JV0vbXRiDrBSxhXfY3bVtpcvRlBFHCKwuzEvVJxbg1ZHWKP3W4vD/e8C8kvX6eq08GQm+eYNk 86TsogOh8cH+FWpTc9tlJyGHNAJueXIjLD9upC4bxWtAiSOM3zvNPNGYtnUbVwCcqf9dENsHG mjyNV2MtO1RcoENwSm6XYY1j3vveDIz9xsqqMgLDwqIndlFTLRHuxfL0XHE1Lf1YetQEHOPuR X33Lgyn+bwEtEaY7xwdnys6hZXKHkZpi1gVCFiHbqDySsrmzPoewnHBLaNVQMfXxYr3c8TQzL clr1ccLtKy2uxEabRcA4vXRoQZUXtgQPnzsrcxonN5f92bso4MgknuyqDaM5uzE3ay9tT4sEo dlIH2sAATuCGKyp61/yMbk= Received-SPF: none client-ip=217.72.192.74; envelope-from=laurent@vivier.eu; helo=mout.kundenserver.de X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=ham 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: , Cc: Richard Henderson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Le 05/05/2021 à 18:03, Philippe Mathieu-Daudé a écrit : > The ABCD / SBCD memory opcodes (introduced in commit fb5543d8200) > don't use their "addr" variable. > > Remove the unused variable and pass a NULL argument instead to > gen_ea_mode(). This fixes warnings generated when building with > CFLAGS=-O3 (using GCC 10.2.1 20201125): > > target/m68k/translate.c: In function ‘disas_sbcd_mem’: > target/m68k/translate.c:897:13: warning: ‘addr’ may be used uninitialized in this function [-Wmaybe-uninitialized] > 897 | delay_set_areg(s, reg0, tmp, false); > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > target/m68k/translate.c:1866:21: note: ‘addr’ was declared here > 1866 | TCGv src, dest, addr; > | ^~~~ > > target/m68k/translate.c: In function ‘disas_abcd_mem’: > target/m68k/translate.c:897:13: warning: ‘addr’ may be used uninitialized in this function [-Wmaybe-uninitialized] > 897 | delay_set_areg(s, reg0, tmp, false); > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > target/m68k/translate.c:1829:21: note: ‘addr’ was declared here > 1829 | TCGv src, dest, addr; > | ^~~~ > It's really strange because ABCD and SBCD support indirect predecrement (mode 4, "-(Ay),-(Ax)"), and if you look into gen_ea_mode() &addr (addrp) is used with mode 4, it is initialized on EA_LOADU to be reused on EA_STORE. The bug is somewhere else... Thanks, Laurent