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[8.43.85.97]) by mx.google.com with ESMTPS id hv13-20020a17090760cd00b007c0b413a43dsi2573689ejc.562.2022.12.16.06.31.58 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 16 Dec 2022 06:31:59 -0800 (PST) Received-SPF: pass (google.com: domain of gcc-patches-bounces+ouuuleilei=gmail.com@gcc.gnu.org designates 8.43.85.97 as permitted sender) client-ip=8.43.85.97; Authentication-Results: mx.google.com; dkim=pass header.i=@gcc.gnu.org header.s=default header.b=marAOZLI; spf=pass (google.com: domain of gcc-patches-bounces+ouuuleilei=gmail.com@gcc.gnu.org designates 8.43.85.97 as permitted sender) smtp.mailfrom="gcc-patches-bounces+ouuuleilei=gmail.com@gcc.gnu.org"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=gnu.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 55D793832367 for ; Fri, 16 Dec 2022 14:31:57 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 55D793832367 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1671201117; bh=wRfRWl1Vw+fvH0bc9VRd9hNQYxJYNnFW665petq6EEM=; h=To:Subject:Date:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:From; b=marAOZLIYTOsvTyK6t/qHkwzJ0z7ZvhZjP3bMv3ql7cqsBs2yqYDKnLnp7NrZN7q0 OX9vFKaZK8f7H4+LgxKfIQkOzDyOVyYzK5hrbhr4pE91dTXyuoFf32L+AOLPpzpIgM JhKL6c7RgI05IKJ0FJj+wh652bGlFPHFPzqgrW04= 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 [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id E41A33832353 for ; Fri, 16 Dec 2022 14:31:08 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org E41A33832353 Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-497-t9uk7bZQOWCLttOMYVs-OA-1; Fri, 16 Dec 2022 09:31:06 -0500 X-MC-Unique: t9uk7bZQOWCLttOMYVs-OA-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 9EF752999B21; Fri, 16 Dec 2022 14:31:06 +0000 (UTC) Received: from localhost (unknown [10.33.36.175]) by smtp.corp.redhat.com (Postfix) with ESMTP id 65FFF49BB6A; Fri, 16 Dec 2022 14:31:06 +0000 (UTC) To: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org Subject: [committed] libstdc++: Fix self-move for std::weak_ptr [PR108118] Date: Fri, 16 Dec 2022 14:31:05 +0000 Message-Id: <20221216143105.118483-1-jwakely@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-Spam-Status: No, score=-12.2 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_H2, SPF_HELO_NONE, 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: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Jonathan Wakely via Gcc-patches From: Jonathan Wakely Reply-To: Jonathan Wakely Errors-To: gcc-patches-bounces+ouuuleilei=gmail.com@gcc.gnu.org Sender: "Gcc-patches" X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1752381384606188361?= X-GMAIL-MSGID: =?utf-8?q?1752381384606188361?= Tested x86_64-lixnu. Pushed to trunk. I'll backport this too. -- >8 -- I think an alternative fix would be something like: _M_ptr = std::exchange(rhs._M_ptr, nullptr); _M_refcount = std::move(rhs._M_refcount); The standard's move-and-swap implementation generates smaller code at all levels except -O0 and -Og, so it seems simplest to just do what the standard says. libstdc++-v3/ChangeLog: PR libstdc++/108118 * include/bits/shared_ptr_base.h (weak_ptr::operator=): Implement as move-and-swap exactly as specified in the standard. * testsuite/20_util/weak_ptr/cons/self_move.cc: New test. --- libstdc++-v3/include/bits/shared_ptr_base.h | 4 +--- .../20_util/weak_ptr/cons/self_move.cc | 19 +++++++++++++++++++ 2 files changed, 20 insertions(+), 3 deletions(-) create mode 100644 libstdc++-v3/testsuite/20_util/weak_ptr/cons/self_move.cc diff --git a/libstdc++-v3/include/bits/shared_ptr_base.h b/libstdc++-v3/include/bits/shared_ptr_base.h index d9230b72203..c22b397a194 100644 --- a/libstdc++-v3/include/bits/shared_ptr_base.h +++ b/libstdc++-v3/include/bits/shared_ptr_base.h @@ -2049,9 +2049,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION __weak_ptr& operator=(__weak_ptr&& __r) noexcept { - _M_ptr = __r._M_ptr; - _M_refcount = std::move(__r._M_refcount); - __r._M_ptr = nullptr; + __weak_ptr(std::move(__r)).swap(*this); return *this; } diff --git a/libstdc++-v3/testsuite/20_util/weak_ptr/cons/self_move.cc b/libstdc++-v3/testsuite/20_util/weak_ptr/cons/self_move.cc new file mode 100644 index 00000000000..c890d2ba94d --- /dev/null +++ b/libstdc++-v3/testsuite/20_util/weak_ptr/cons/self_move.cc @@ -0,0 +1,19 @@ +// { dg-do run { target c++11 } } + +#include +#include + +void +test_self_move() +{ + std::shared_ptr sp(new int(66)); + std::weak_ptr wp(sp); + wp = std::move(wp); // PR libstdc++/108118 + std::shared_ptr sp2(wp); + VERIFY(sp2 == sp); +} + +int main() +{ + test_self_move(); +}