From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id 331FB385840F for ; Fri, 24 Feb 2023 12:26:36 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 331FB385840F Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1677241595; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=7NrGpHE3tAMXquB9kuTjvdaVe4EW9GiOwqrgvhznY2Q=; b=TXwpKHsQbLxnHB31m0dn2ZZJBD4m6H9PjA5IjI/vYkPrDXYRx9JM+u/w+VOVOgtxtdLn03 3LVNr/0LPqpUTdSz6l/LdunKjiek+mJMwFNDJcRMBw2QE29ciJHpEfY6xU1hWgc1QiD/Jp QMq6rPot0+LLIHt7bSxzTrhdhBP5VT8= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-562-WrEccJRsOLeCGc-uK7ZKpA-1; Fri, 24 Feb 2023 07:26:32 -0500 X-MC-Unique: WrEccJRsOLeCGc-uK7ZKpA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 1DE1F811E6E; Fri, 24 Feb 2023 12:26:32 +0000 (UTC) Received: from tucnak.zalov.cz (unknown [10.39.192.62]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D63FEC15BA0; Fri, 24 Feb 2023 12:26:31 +0000 (UTC) Received: from tucnak.zalov.cz (localhost [127.0.0.1]) by tucnak.zalov.cz (8.17.1/8.17.1) with ESMTPS id 31OCQTRe864518 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Fri, 24 Feb 2023 13:26:29 +0100 Received: (from jakub@localhost) by tucnak.zalov.cz (8.17.1/8.17.1/Submit) id 31OCQSfL864517; Fri, 24 Feb 2023 13:26:28 +0100 Date: Fri, 24 Feb 2023 13:26:28 +0100 From: Jakub Jelinek To: Richard Biener Cc: Jonathan Wakely , gcc-patches@gcc.gnu.org Subject: Re: [PATCH 2/2] Avoid default-initializing auto_vec storage, fix vec Message-ID: Reply-To: Jakub Jelinek References: <20230224114444.7E2CE13246@imap2.suse-dmz.suse.de> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 3.1 on 10.11.54.8 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Spam-Status: No, score=-3.3 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=ham 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 Fri, Feb 24, 2023 at 12:15:04PM +0000, Richard Biener wrote: > > > Also, I think it needs to be MAX (N, 2) instead of N, because auto_vec > > > ctors use MAX (N, 2). We could also change all those to MAX (N, 1) > > > now, but it can't be N because m_data[sizeof (T) * 0] is invalid in > > > standard C. > > I've removed the MAX (N, 2) now, I think that N == 0 cannot happen > because we have a specialization covering that. So we know N is > at least 1. I think you're right. > > > Anyway, I wonder if you get the -Werror=stringop-overflow= errors during > > > bootstrap that I got with my version or not. > > Yes, I get this as well, not sure how to suppress it. I guess there's > no standard way to get at the address after some object without going > through uintptr obfuscation - and obviously we do not want to have > that (and if we optimize it away that doesn't help the diagnostic ...) I think we need to look at the exact IL on which it warns and see what our options are. Jakub