From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2181) id 303283858436; Wed, 22 Mar 2023 23:26:55 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 303283858436 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1679527615; bh=H9gBPYPS5cqmf+leg2JY0nf5t1R8cn2+qwpa2oMa3kw=; h=From:To:Subject:Date:From; b=eV+sGeMRVmXOJa9G2WJMWXtc4zEsxq96DDbbqwg2YoZDML5deMHvhCB3RauGDqxPF DOcTExUTCzcO1XIKBV+LuQ+29zjx69OWOUE7Lo2UNwamNF78sXYEZSkpU4OFO++JsU 0abocomEhumS7JbBu4PqNSIE7vCb6xVFRPG9+gOA= MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: Jonathan Wakely To: gcc-cvs@gcc.gnu.org, libstdc++-cvs@gcc.gnu.org Subject: [gcc r13-6816] libstdc++: Fix assigning nullptr to std::atomic> (LWG 3893) X-Act-Checkin: gcc X-Git-Author: Jonathan Wakely X-Git-Refname: refs/heads/master X-Git-Oldrev: 6b2740946d26ffde7e1318f24bae00443ece387d X-Git-Newrev: a495b738e4a89a8104798d005fd09474bbb916ff Message-Id: <20230322232655.303283858436@sourceware.org> Date: Wed, 22 Mar 2023 23:26:55 +0000 (GMT) List-Id: https://gcc.gnu.org/g:a495b738e4a89a8104798d005fd09474bbb916ff commit r13-6816-ga495b738e4a89a8104798d005fd09474bbb916ff Author: Jonathan Wakely Date: Wed Mar 22 21:54:24 2023 +0000 libstdc++: Fix assigning nullptr to std::atomic> (LWG 3893) LWG voted this to Tentatively Ready recently. libstdc++-v3/ChangeLog: * include/bits/shared_ptr_atomic.h (atomic::operator=(nullptr_t)): Add overload, as per LWG 3893. * testsuite/20_util/shared_ptr/atomic/atomic_shared_ptr.cc: Check assignment from nullptr. Diff: --- libstdc++-v3/include/bits/shared_ptr_atomic.h | 6 ++++++ .../testsuite/20_util/shared_ptr/atomic/atomic_shared_ptr.cc | 9 +++++++++ 2 files changed, 15 insertions(+) diff --git a/libstdc++-v3/include/bits/shared_ptr_atomic.h b/libstdc++-v3/include/bits/shared_ptr_atomic.h index d142616f485..2295b48e732 100644 --- a/libstdc++-v3/include/bits/shared_ptr_atomic.h +++ b/libstdc++-v3/include/bits/shared_ptr_atomic.h @@ -650,6 +650,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION operator=(shared_ptr<_Tp> __desired) noexcept { _M_impl.swap(__desired, memory_order_seq_cst); } + // _GLIBCXX_RESOLVE_LIB_DEFECTS + // 3893. LWG 3661 broke atomic> a; a = nullptr; + void + operator=(nullptr_t) noexcept + { store(nullptr); } + shared_ptr<_Tp> exchange(shared_ptr<_Tp> __desired, memory_order __o = memory_order_seq_cst) noexcept diff --git a/libstdc++-v3/testsuite/20_util/shared_ptr/atomic/atomic_shared_ptr.cc b/libstdc++-v3/testsuite/20_util/shared_ptr/atomic/atomic_shared_ptr.cc index a1902745a3e..54cf2621ea1 100644 --- a/libstdc++-v3/testsuite/20_util/shared_ptr/atomic/atomic_shared_ptr.cc +++ b/libstdc++-v3/testsuite/20_util/shared_ptr/atomic/atomic_shared_ptr.cc @@ -145,6 +145,14 @@ test_counting() VERIFY( counter == 2 ); } +void +test_lwg3893() +{ + // LWG 3893. LWG 3661 broke atomic> a; a = nullptr; + std::atomic> a; + a = nullptr; +} + int main() { @@ -152,4 +160,5 @@ main() test_atomic_shared_ptr(); test_wait_notify(); test_counting(); + test_lwg3893(); }