From patchwork Fri Sep 12 11:06:34 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jonathan Wakely X-Patchwork-Id: 120129 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id C6B693857C7F for ; Fri, 12 Sep 2025 11:10:02 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org C6B693857C7F Authentication-Results: sourceware.org; dkim=pass (1024-bit key, unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=CqTFpc2E X-Original-To: gcc-patches@gcc.gnu.org Delivered-To: gcc-patches@gcc.gnu.org Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTP id A91873857C4F for ; Fri, 12 Sep 2025 11:07:25 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org A91873857C4F Authentication-Results: sourceware.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com ARC-Filter: OpenARC Filter v1.0.0 sourceware.org A91873857C4F Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1757675245; cv=none; b=PXTiUOMMSTx8sxHoWDgMRT5iLIEOmXlQXWGvtExdeimlnIcyoDi9Lan0CyHz4lyT7yNNRwX3MTJjqFx4ljhqXGYPx4C24LWcKMlsw/ZH4PgenJ+TlbCg7FQl+ehOL+HyFWIWXk/rUSuI/fdhtYBR3+WQQ9RFMzQdsvHVHhQbqBE= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1757675245; c=relaxed/simple; bh=jeymc8R9mWMz/1u/p+k2UyCRL5QwXgY0ijO6ghLWA/0=; h=DKIM-Signature:From:To:Subject:Date:Message-ID:MIME-Version; b=fmi3QKTDOEg7G7vdOgOeq5LcTYlbCobtWWTeJg6KFIDb7wf1r8ZGMVlMUnCWeCiPCCINa9TDuswLWsabz7WhjpWKMtTzit4nxaFCkhSp2gmTk2yby/xgY2hiIPgvDnppgWKQ43BzMG5oKil7G2JNoBScbmwoUPhcMwaqfs9QoZk= ARC-Authentication-Results: i=1; server2.sourceware.org DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org A91873857C4F DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1757675245; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=RW65uHEtG3/RUYwivicOKYToKysJmPRFmQQnPOGrCLQ=; b=CqTFpc2EXwCgYRxfAXxUH5Zivx4CmUVbAgJHIiS8s7P1/gyBPtSRxciiArLsQu/aC/iHRy KXRua18MKictL5Ll2h/UNPPuNtvwYNywmp7wvz1jLGLHatXpJmalNPhN8QeoCMsjfjuC8d cAcA+SutHpMnRZxA5CENyZo/ug8apzI= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-678-H5mWm0C_OJaVz7rTZ_JEFw-1; Fri, 12 Sep 2025 07:07:24 -0400 X-MC-Unique: H5mWm0C_OJaVz7rTZ_JEFw-1 X-Mimecast-MFC-AGG-ID: H5mWm0C_OJaVz7rTZ_JEFw_1757675243 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 114E71955D9D; Fri, 12 Sep 2025 11:07:23 +0000 (UTC) Received: from zen.kayari.org (unknown [10.42.28.196]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 190981800452; Fri, 12 Sep 2025 11:07:21 +0000 (UTC) From: Jonathan Wakely To: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org Subject: [committed] libstdc++: Fix bootstrap failure in atomicity.cc Date: Fri, 12 Sep 2025 12:06:34 +0100 Message-ID: <20250912110720.1942819-1-jwakely@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: CPKlohLvmGrs4YQdWcu4jG99ptRiBxHWdOyYRClwR1E_1757675243 X-Mimecast-Originator: redhat.com X-Spam-Status: No, score=-12.3 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H5, RCVD_IN_MSPIKE_WL, RCVD_IN_VALIDITY_RPBL_BLOCKED, RCVD_IN_VALIDITY_SAFE_BLOCKED, SPF_HELO_PASS, 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 X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: gcc-patches-bounces~patchwork=sourceware.org@gcc.gnu.org My r16-3810-g6456da6bab8a2c changes broke bootstrap for targets that use the mutex-based atomic helpers. This fixes it by casting away the unnecessary volatile-qualification on the _Atomic_word* before passing it to __exchange_and_add_single. libstdc++-v3/ChangeLog: * config/cpu/generic/atomicity_mutex/atomicity.h (__exchange_and_add): Use const_cast to remove volatile. --- Tested powerpc64le-linux, bootstrapped on msp430-elf and pru-unknown-elf. Pushed to trunk. libstdc++-v3/config/cpu/generic/atomicity_mutex/atomicity.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/libstdc++-v3/config/cpu/generic/atomicity_mutex/atomicity.h b/libstdc++-v3/config/cpu/generic/atomicity_mutex/atomicity.h index 7d5772d54840..d088f69fe9a4 100644 --- a/libstdc++-v3/config/cpu/generic/atomicity_mutex/atomicity.h +++ b/libstdc++-v3/config/cpu/generic/atomicity_mutex/atomicity.h @@ -44,7 +44,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION __exchange_and_add(volatile _Atomic_word* __mem, int __val) throw () { __gnu_cxx::__scoped_lock sentry(get_atomic_mutex()); - return __gnu_cxx::__exchange_and_add_single(__mem, __val); + // The volatile qualification is meaningless. All changes to the memory + // location happen while this mutex is locked so it's not volatile at all. + auto __mem2 = const_cast<_Atomic_word*>(__mem); + return __gnu_cxx::__exchange_and_add_single(__mem2, __val); } void