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 37259385C6E9 for ; Wed, 26 Jul 2023 16:03:51 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 37259385C6E9 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1690387430; 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=wWA0LS707glfYa6NLJ5DqdIKbIHQNn+SpaTgJZwAjNQ=; b=NoJ2EdxTSARZR2sBhETp1BSm8pmO0DUurR5h18/EW0+YrKIzce7EvCTK5txT8x6n/Lj835 xUPa3tgYQ+ruweuz5cFM/IKOtvPAkeM+iQE649kvbjI/sVdMFHPzbamBVvebkboR0ly4UW aJ1Tj0IaONskNoCYOv9FmYJMDj6Dqls= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-659-FRv8BBxKOcyMFVZenMEoUg-1; Wed, 26 Jul 2023 12:03:45 -0400 X-MC-Unique: FRv8BBxKOcyMFVZenMEoUg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 619A385A58A; Wed, 26 Jul 2023 16:03:45 +0000 (UTC) Received: from localhost (unknown [10.42.28.198]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2701B40C206F; Wed, 26 Jul 2023 16:03:45 +0000 (UTC) From: Jonathan Wakely To: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org Subject: [committed] libstdc++: Avoid bogus overflow warnings in std::vector [PR110807] Date: Wed, 26 Jul 2023 17:03:21 +0100 Message-ID: <20230726160344.220228-1-jwakely@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-13.2 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_H4,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE,TXREP,T_SCC_BODY_TEXT_LINE,URI_HEX autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: Tested x86_64-linux. Pushed to trunk. Backport to gcc-13 will come after the 13.2 release. -- >8 -- GCC thinks the allocation can alter the object being copied if it's globally reachable, so doesn't realize that [x.begin(), x.end()) after the allocation is the same as x.size() before it. This causes a testsuite failure when testing with -D_GLIBCXX_DEBUG: FAIL: 23_containers/vector/bool/swap.cc (test for excess errors) A fix is to move the calls to x.begin() and x.end() to before the allocation. A similar problem exists in vector::_M_insert_range where *this is globally reachable, as reported in PR libstdc++/110807. That can also be fixed by moving calls to begin() and end() before the allocation. libstdc++-v3/ChangeLog: PR libstdc++/110807 * include/bits/stl_bvector.h (vector(const vector&)): Access iterators before allocating. * include/bits/vector.tcc (vector::_M_insert_range): Likewise. * testsuite/23_containers/vector/bool/110807.cc: New test. --- libstdc++-v3/include/bits/stl_bvector.h | 3 ++- libstdc++-v3/include/bits/vector.tcc | 5 +++-- .../testsuite/23_containers/vector/bool/110807.cc | 14 ++++++++++++++ 3 files changed, 19 insertions(+), 3 deletions(-) create mode 100644 libstdc++-v3/testsuite/23_containers/vector/bool/110807.cc diff --git a/libstdc++-v3/include/bits/stl_bvector.h b/libstdc++-v3/include/bits/stl_bvector.h index ad462c5933c..8d18bcaffd4 100644 --- a/libstdc++-v3/include/bits/stl_bvector.h +++ b/libstdc++-v3/include/bits/stl_bvector.h @@ -773,8 +773,9 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER vector(const vector& __x) : _Base(_Bit_alloc_traits::_S_select_on_copy(__x._M_get_Bit_allocator())) { + const_iterator __xbegin = __x.begin(), __xend = __x.end(); _M_initialize(__x.size()); - _M_copy_aligned(__x.begin(), __x.end(), begin()); + _M_copy_aligned(__xbegin, __xend, begin()); } #if __cplusplus >= 201103L diff --git a/libstdc++-v3/include/bits/vector.tcc b/libstdc++-v3/include/bits/vector.tcc index f592c72dec2..ada396c9b30 100644 --- a/libstdc++-v3/include/bits/vector.tcc +++ b/libstdc++-v3/include/bits/vector.tcc @@ -980,11 +980,12 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER { const size_type __len = _M_check_len(__n, "vector::_M_insert_range"); + const iterator __begin = begin(), __end = end(); _Bit_pointer __q = this->_M_allocate(__len); iterator __start(std::__addressof(*__q), 0); - iterator __i = _M_copy_aligned(begin(), __position, __start); + iterator __i = _M_copy_aligned(__begin, __position, __start); __i = std::copy(__first, __last, __i); - iterator __finish = std::copy(__position, end(), __i); + iterator __finish = std::copy(__position, __end, __i); this->_M_deallocate(); this->_M_impl._M_end_of_storage = __q + _S_nword(__len); this->_M_impl._M_start = __start; diff --git a/libstdc++-v3/testsuite/23_containers/vector/bool/110807.cc b/libstdc++-v3/testsuite/23_containers/vector/bool/110807.cc new file mode 100644 index 00000000000..5c019bd9524 --- /dev/null +++ b/libstdc++-v3/testsuite/23_containers/vector/bool/110807.cc @@ -0,0 +1,14 @@ +// { dg-options "-O2" } +// { dg-do compile } + +// Bug 110807 +// Copy list initialisation of a vector raises a warning with -O2 + +#include + +std::vector byCallSpread; + +void f() +{ + byCallSpread = {true}; +} -- 2.41.0