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 900F03858416 for ; Thu, 21 Oct 2021 21:18:17 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 900F03858416 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-48-A_iOzsbQM5mN6o488bR-mw-1; Thu, 21 Oct 2021 17:18:13 -0400 X-MC-Unique: A_iOzsbQM5mN6o488bR-mw-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id F38BA10A8E00; Thu, 21 Oct 2021 21:18:12 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.39.194.104]) by smtp.corp.redhat.com (Postfix) with ESMTPS id CECAE641A7; Thu, 21 Oct 2021 21:18:11 +0000 (UTC) From: Florian Weimer To: Adhemerval Zanella via Libc-alpha Subject: Re: [PATCH v7] String: Add support for __memcmpeq() ABI on all targets References: <20210927203827.2852935-1-goldstein.w.n@gmail.com> <20210929151743.3351092-1-goldstein.w.n@gmail.com> <8ee11473-cdfd-3dbe-47a1-dffddc996b34@linaro.org> <759a52ae-1cca-6b1b-919f-fea7744594fc@linaro.org> Date: Thu, 21 Oct 2021 23:18:09 +0200 In-Reply-To: <759a52ae-1cca-6b1b-919f-fea7744594fc@linaro.org> (Adhemerval Zanella via Libc-alpha's message of "Thu, 21 Oct 2021 17:06:34 -0300") Message-ID: <87wnm6m60e.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-6.4 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 21 Oct 2021 21:18:18 -0000 * Adhemerval Zanella via Libc-alpha: > On 21/10/2021 17:01, Noah Goldstein wrote: >> My understanding is that since we are only exporting this symbol for >> compiler use (to optimize boolean use of 'memcmp()') we weren't >> planning to add a manual entry. > > But you are exporting the double underscore symbol on an installed > header, so it would be visible to users as well. The advantage of exporting it is that GCC can perform the memcmp =E2=86=92 __memcmpeq if and only if a suitable declaration of __memcmpeq is in scope. Maybe we could add #pragma GCC poison for __memcmpeq. Or add a new pragma to enable the transformation. Thanks, Florian