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 [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id 24E5E3858401 for ; Mon, 19 Jun 2023 11:20:35 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 24E5E3858401 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=1687173634; 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=xM0VccoCAE9TJGA2PSduo3+h+m1BGUIO6LSpkw/SHe4=; b=KTiZdMoCvcBqlreXWGCnESS4VdnXXNYFumo3/jAP/l6rgcW4PhxhhE8dF8n69x5mwu6ilG zGTNISJhhje5ZIrHGKL4beOBee1vbWw7SqHHvgS1PbbNWFsnGi+H3EKAxuOA7Yr4VDOnYf 9BHDoeqaogdldXa1cR42C05L0/rPVvI= 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-515-s-gbb1yBM-io1k_pfpLjZA-1; Mon, 19 Jun 2023 07:20:33 -0400 X-MC-Unique: s-gbb1yBM-io1k_pfpLjZA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id EEF4E85A58C; Mon, 19 Jun 2023 11:20:32 +0000 (UTC) Received: from tucnak.zalov.cz (unknown [10.39.194.30]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B1A1A2026D49; Mon, 19 Jun 2023 11:20:32 +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 35JBKUpn1675564 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Mon, 19 Jun 2023 13:20:30 +0200 Received: (from jakub@localhost) by tucnak.zalov.cz (8.17.1/8.17.1/Submit) id 35JBKTOW1675563; Mon, 19 Jun 2023 13:20:29 +0200 Date: Mon, 19 Jun 2023 13:20:29 +0200 From: Jakub Jelinek To: Jan Hubicka Cc: Jonathan Wakely , gcc-patches@gcc.gnu.org Subject: Re: [libstdc++] Improve M_check_len Message-ID: Reply-To: Jakub Jelinek References: MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 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=-3.4 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_NONE,TXREP,T_SCC_BODY_TEXT_LINE 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 Mon, Jun 19, 2023 at 01:05:36PM +0200, Jan Hubicka via Gcc-patches wrote: > - if (max_size() - size() < __n) > - __throw_length_error(__N(__s)); > + const size_type __max_size = max_size(); > + // On 64bit systems vectors can not reach overflow by growing > + // by small sizes; before this happens, we will run out of memory. > + if (__builtin_constant_p(__n) > + && __builtin_constant_p(__max_size) > + && sizeof(ptrdiff_t) >= 8 > + && __max_size * sizeof(_Tp) >= ((ptrdiff_t)1 << 60) Isn't there a risk of overlow in the __max_size * sizeof(_Tp) computation? Jakub