From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ej1-x636.google.com (mail-ej1-x636.google.com [IPv6:2a00:1450:4864:20::636]) by sourceware.org (Postfix) with ESMTPS id 1771D3858009 for ; Sat, 13 Feb 2021 14:25:52 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 1771D3858009 Received: by mail-ej1-x636.google.com with SMTP id b9so4056835ejy.12 for ; Sat, 13 Feb 2021 06:25:52 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:user-agent:in-reply-to:references :mime-version:content-transfer-encoding:subject:to:from:message-id; bh=64eUqdf3RPDVQcjAB1wq6lVcFwldAR+lHc2bZ3HQoA0=; b=JvXfRCkYt8DLliol6cIjPGaKO3oJXUTqA2z+QHSyWsXklSCg88H00KCOQg9boag7VA M9wvDCFvixSOeodAgKd9NSuc4R8pMOM1RqUZ4FkhiKShQMFTO6SlJeWd9AXbdseV1qIX ZxJeqOOStuaA4QpOAWecoA4grnHa4xdudJsMudNE1nZJ7+17l+znPZ2v0mop9QjjSKGh qmjqI7wLLar6B75TqCaHOQ5S9ZYZl5u7Y6Rzf0r+uoZ2mj5RxPSlcHdyVabDVLChY+Pn jifAMcwEMXOZBBS5MYNyWTIJmXi9YGhxkPigz05Z59tr+ms3AYiTr8Ad8337ksjA6aN7 +rHg== X-Gm-Message-State: AOAM530VRERvJE5p9bRCvdtbmTGocO9W3ZwlMwSScuxQR0a7gK5rFwX/ DAGH/PLi2HnyuUcW2ndu7tymzwI8f4k= X-Google-Smtp-Source: ABdhPJzB2PkKPDB3HsJhu2ghwxHDUTRggXM6+OnGv3L8upnuY/Zk5g/C8AVkmhXz1NKZzxF64bI6rw== X-Received: by 2002:a17:906:fb91:: with SMTP id lr17mr7771886ejb.186.1613226350961; Sat, 13 Feb 2021 06:25:50 -0800 (PST) Received: from [192.168.178.32] (dynamic-077-007-074-046.77.7.pool.telefonica.de. [77.7.74.46]) by smtp.gmail.com with ESMTPSA id u16sm7296160eds.71.2021.02.13.06.25.50 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sat, 13 Feb 2021 06:25:50 -0800 (PST) Date: Sat, 13 Feb 2021 15:25:48 +0100 User-Agent: K-9 Mail for Android In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: bug in DSE? To: GCC , Marc Glisse , Andrew MacLeod From: Richard Biener Message-ID: <37E68E93-64E3-4690-A65C-B4FBDEB4B2EA@gmail.com> X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, RCVD_IN_BARRACUDACENTRAL, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=no autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: gcc@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 13 Feb 2021 14:25:54 -0000 On February 13, 2021 12:20:48 AM GMT+01:00, Marc Glisse wrote: >On Fri, 12 Feb 2021, Andrew MacLeod via Gcc wrote: > >> I dont't want to immediately open a PR,=C2=A0 so I'll just ask about=20 >> testsuite/gcc=2Edg/pr83609=2Ec=2E >> >> the compilation string=C2=A0 is >> =C2=A0 -O2 -fno-tree-forwprop -fno-tree-ccp -fno-tree-fre -fno-tree-pre= =20 >> -fno-code-hoisting >> >> Which passes as is=2E >> >> if I however add=C2=A0=C2=A0 -fno-tree-vrp=C2=A0=C2=A0 as well, then it= looks like dead >store=20 >> maybe does something wong=2E=2E=2E >> >> with EVRP running, we translate function foo() from >> >> >> complex float foo () >> { >> =C2=A0 complex float c; >> =C2=A0 complex float * c=2E0_1; >> =C2=A0 complex float _4; >> >> =C2=A0 : >> =C2=A0 c=2E0_1 =3D &c; >> =C2=A0 MEM[(long long unsigned int *)c=2E0_1] =3D 1311768467463790320; >> =C2=A0 _4 =3D c; > >Isn't that a clear violation of strict aliasing? Yes=2E We try DWIM if we see the must-alias though=2E Please see what the = testcase was added for and eventually consider adding -fno-strict-aliasing= =2E=20