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 DE5CA3858D1E for ; Tue, 8 Feb 2022 14:25:40 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org DE5CA3858D1E Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-101-l8doXBN5PGiSK40uRbnK4A-1; Tue, 08 Feb 2022 09:25:34 -0500 X-MC-Unique: l8doXBN5PGiSK40uRbnK4A-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1060146860; Tue, 8 Feb 2022 14:25:33 +0000 (UTC) Received: from localhost (unknown [10.33.37.88]) by smtp.corp.redhat.com (Postfix) with ESMTP id B522C79529; Tue, 8 Feb 2022 14:25:32 +0000 (UTC) From: Jonathan Wakely To: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org Subject: [committed] libstdc++: Add comment to acinclude.m4 Date: Tue, 8 Feb 2022 14:25:31 +0000 Message-Id: <20220208142531.3075188-1-jwakely@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII" X-Spam-Status: No, score=-13.3 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, KAM_NUMSUBJECT, RCVD_IN_DNSWL_LOW, SPF_HELO_NONE, SPF_NONE, TXREP, T_SCC_BODY_TEXT_LINE 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: libstdc++@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libstdc++ mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 08 Feb 2022 14:25:42 -0000 Tested x86_64-linux, pushed to trunk. libstdc++-v3/ChangeLog: * acinclude.m4 (GLIBCXX_ENABLE_LOCK_POLICY): Add comment about checking for CAS on correct word size. --- libstdc++-v3/acinclude.m4 | 2 ++ 1 file changed, 2 insertions(+) diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4 index 7cc52f4db96..f53461c85a5 100644 --- a/libstdc++-v3/acinclude.m4 +++ b/libstdc++-v3/acinclude.m4 @@ -3609,6 +3609,8 @@ AC_DEFUN([GLIBCXX_ENABLE_LOCK_POLICY], [ ac_save_CXXFLAGS="$CXXFLAGS" dnl Why do we care about 2-byte CAS on targets with 4-byte _Atomic_word?! + dnl Why don't we check 8-byte CAS for sparc64, where _Atomic_word is long?! + dnl New targets should only check for CAS for the _Atomic_word type. AC_TRY_COMPILE([ #if ! defined __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 # error "No 2-byte compare-and-swap" -- 2.34.1