From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 2435 invoked by alias); 10 Apr 2017 16:35:11 -0000 Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org Received: (qmail 1691 invoked by uid 89); 10 Apr 2017 16:35:11 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-3.2 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE,RCVD_IN_SORBS_SPAM autolearn=no version=3.3.2 spammy=Hx-languages-length:952 X-HELO: mail-io0-f172.google.com Received: from mail-io0-f172.google.com (HELO mail-io0-f172.google.com) (209.85.223.172) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Mon, 10 Apr 2017 16:35:10 +0000 Received: by mail-io0-f172.google.com with SMTP id t68so70621976iof.0 for ; Mon, 10 Apr 2017 09:35:11 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=CK0xiidTBhqJVWFQWp7bSxviwjwK8BCiv/9Y4qL0EcI=; b=JTRPgVggJS1Cn9hUQFWs3BIt+jDjBVcKlURL63O7MuOcqJ6/QHahZXarSwq8msaEII xGilRwZYbgCEqlucD7jDnt5qdTPNoeOJUZQ0WUUqgnyMJeCLZ1Gra0wizHw11K1lfGPS PLWg9jj9zFEte/V12QrTvDxvWz82CArvSQ4EWAYhnzuAigx9zJngSegWLU79pKZ82Dqz FdPOSJcfxanoxSIVidPmw5eIdf3JdpVyh6AvkkyDnep+naLzA2lzMUKno7cTwTv3ZCJN aGivTpmvlAJzQVP9M0VwDITHXDxjpmadBHCzujlrxbXBHuvqCXG32TjPicaI1+ZP5Dt9 P4JQ== X-Gm-Message-State: AN3rC/64LrLf208Nc8afdIarnDHNtR+2ZDQqQcztuILry6xIoKkKuFp5hPTrP5sAxjiazPIITw1dYr8WmfHrpqqp X-Received: by 10.36.210.198 with SMTP id z189mr12434514itf.80.1491842108768; Mon, 10 Apr 2017 09:35:08 -0700 (PDT) MIME-Version: 1.0 Received: by 10.107.59.23 with HTTP; Mon, 10 Apr 2017 09:34:48 -0700 (PDT) In-Reply-To: References: <20170405160333.GR4425@redhat.com> <20170405160849.GV17461@tucnak> From: Jason Merrill Date: Mon, 10 Apr 2017 16:35:00 -0000 Message-ID: Subject: Re: [PATCH] Add a new type attribute always_alias (PR79671) To: Richard Biener Cc: Bernd Edlinger , Jakub Jelinek , Jonathan Wakely , Florian Weimer , GCC Patches , Jeff Law Content-Type: text/plain; charset=UTF-8 X-IsSubscribed: yes X-SW-Source: 2017-04/txt/msg00466.txt.bz2 On Mon, Apr 10, 2017 at 11:30 AM, Richard Biener wrote: > On Mon, 10 Apr 2017, Jason Merrill wrote: >> On Mon, Apr 10, 2017 at 8:50 AM, Richard Biener wrote: >> > * tree.c (build_cplus_array_type): Set TYPE_TYPELESS_STORAGE >> > for arrays of unsigned char or std::byte. >> >> I think it would be good to have a flag to select whether these >> semantics apply to any char variant and std::byte, only unsigned char >> and std::byte, or only std::byte. > > Any suggestion? Not sure we really need it (I'm hesitant to write > all the testcases to verify it actually works). Well, there's existing code that uses plain char (e.g. boost) that I want to support. If there's a significant optimization penalty for allowing that, we probably also want to be able to limit the impact. If there isn't much penalty, let's just support all char variants. Jason