From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from esa1.mentor.iphmx.com (esa1.mentor.iphmx.com [68.232.129.153]) by sourceware.org (Postfix) with ESMTPS id 0C9543858D28 for ; Fri, 29 Dec 2023 00:53:08 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 0C9543858D28 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=codesourcery.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=mentor.com ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 0C9543858D28 Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=68.232.129.153 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1703811190; cv=none; b=ujYa8rEFnBFyhSb6zEPsC0KFTvbTNUa5rZ+J/oPbWyBjzMgcD5VBp6dIaxN4vNHDWl88ih3R4X6AoTUr9A54fPoqOIs3mzdxp+OSpCr4PyDr5oJIIklsHOMuJoFIiLgbFepRd/WegVASbZ53hFiSUxkP9JlNR1m3/3SBH+YjZZ0= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1703811190; c=relaxed/simple; bh=Q0rIxB/cMEHU+h1lF4L9AdNgbHLAMKM3fGr+6bKxqhs=; h=Date:From:To:Subject:Message-ID:MIME-Version; b=UyITzdpMb2q7k9HbQUQCzS51FpZQA1kBN4Wf8JNrN9hyUrvMdau6108g9LWsLo6M7ZH9Vbc8KLJam7GKjjMvjA8yKMLt6VhEjSl7NrXSnHGUhPPleDHrPjpPpVrXK2Ued6KJ4+b6XBNSUzgMYUNGY5OfC/wxrJUO8Mm8zhOrGrg= ARC-Authentication-Results: i=1; server2.sourceware.org X-CSE-ConnectionGUID: ic+PrtYoTa6RKS62G7r7BQ== X-CSE-MsgGUID: G44rdFHGT9mQ+uRfRZl7OQ== X-IronPort-AV: E=Sophos;i="6.04,313,1695715200"; d="scan'208";a="29915822" Received: from orw-gwy-02-in.mentorg.com ([192.94.38.167]) by esa1.mentor.iphmx.com with ESMTP; 28 Dec 2023 16:53:07 -0800 IronPort-SDR: uuZp8EAYRg6CS06vbNAMQ+bn4EXBRdhF6y1grG+MFRZsRVv/PmmfdW/DDZqcMEuk3ZG3sMNfv+ EtxjCyJ/R1XckeC+rz/TbujIf8gkj6mHKPzX02nth+wW5vhKLiMamqfHcCGTaYF/WIWcTDeVGu aVxNVXX0JmO7dh1HH7bgq/FGO6gxB/zkiZrkyk7Lu+MfGjnDWh4E4jsHYmoLKwR2u0ucQfp3zw nz5430wWhZelS0nQBqZOi2zpA4JIo9vzmzQZwZXTuqHENcWqCaFOj5VZG1GPkWaUzUaFRnH5gZ BJc= Date: Fri, 29 Dec 2023 00:52:58 +0000 From: Joseph Myers To: Mike Frysinger CC: Subject: Re: [PATCH] sim: warnings: disable -Wshift-negative-value In-Reply-To: <20231224082639.18038-1-vapier@gentoo.org> Message-ID: <9b592c16-dc57-1bb7-5438-26c794d61d1c@codesourcery.com> References: <20231224082639.18038-1-vapier@gentoo.org> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" X-Originating-IP: [137.202.0.90] X-ClientProxiedBy: svr-ies-mbx-14.mgc.mentorg.com (139.181.222.14) To svr-ies-mbx-10.mgc.mentorg.com (139.181.222.10) X-Spam-Status: No, score=-3102.5 required=5.0 tests=BAYES_00,HEADER_FROM_DIFFERENT_DOMAINS,KAM_DMARC_STATUS,SPF_HELO_PASS,SPF_PASS,TXREP,T_SCC_BODY_TEXT_LINE autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On Sun, 24 Dec 2023, Mike Frysinger wrote: > The sim expects left shift operations on negative values to have two's > compliment behavior, and right shift operations to sign extend. In C89, > this was not explicitly mentioned. In C90, this was changed to undefined > behavior. In C23, this was settled as the behavior we want in N2412 [1]. No, there has been no change in C23 to the rules for which shifts are undefined. The change made was to make *representations* of integer types defined as two's complement; there were no changes to semantics of *operations* on such types. -- Joseph S. Myers joseph@codesourcery.com