public inbox for libstdc++-cvs@sourceware.org help / color / mirror / Atom feed
From: Iain D Sandoe <iains@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org, libstdc++-cvs@gcc.gnu.org Subject: [gcc/devel/c++-coroutines] libstdc++: Fix char_traits move with overlap Date: Mon, 15 Jun 2020 20:16:29 +0000 (GMT) [thread overview] Message-ID: <20200615201629.EB5D0388C02E@sourceware.org> (raw) https://gcc.gnu.org/g:eb11134d0c4e4db623aefe433c9613632ef8618e commit eb11134d0c4e4db623aefe433c9613632ef8618e Author: Paul Keir <paul.keir@uws.ac.uk> Date: Mon Jun 15 14:31:26 2020 +0100 libstdc++: Fix char_traits move with overlap Upon constexpr evaluation, char_traits move uses copy_backward, but its last argument should be to the range end rather than its beginning. 2020-06-12 Paul Keir <paul.keir@uws.ac.uk> * include/bits/char_traits.h (char_traits::move): constexpr move with overlap was using copy_backward incorrectly. * testsuite/21_strings/char_traits/requirements/constexpr_functions_c++20.cc: New test. Diff: --- libstdc++-v3/include/bits/char_traits.h | 2 +- .../requirements/constexpr_functions_c++20.cc | 52 ++++++++++++++++++++++ 2 files changed, 53 insertions(+), 1 deletion(-) diff --git a/libstdc++-v3/include/bits/char_traits.h b/libstdc++-v3/include/bits/char_traits.h index c6da184e4bd..c623a6713f6 100644 --- a/libstdc++-v3/include/bits/char_traits.h +++ b/libstdc++-v3/include/bits/char_traits.h @@ -196,7 +196,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION if (std::is_constant_evaluated()) { if (__s1 > __s2 && __s1 < __s2 + __n) - std::copy_backward(__s2, __s2 + __n, __s1); + std::copy_backward(__s2, __s2 + __n, __s1 + __n); else std::copy(__s2, __s2 + __n, __s1); return __s1; diff --git a/libstdc++-v3/testsuite/21_strings/char_traits/requirements/constexpr_functions_c++20.cc b/libstdc++-v3/testsuite/21_strings/char_traits/requirements/constexpr_functions_c++20.cc new file mode 100644 index 00000000000..6358640c1cb --- /dev/null +++ b/libstdc++-v3/testsuite/21_strings/char_traits/requirements/constexpr_functions_c++20.cc @@ -0,0 +1,52 @@ +// { dg-options "-std=gnu++2a" } +// { dg-do compile { target c++2a } } + +// Copyright (C) 2017-2020 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 3, or (at your option) +// any later version. + +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. + +// You should have received a copy of the GNU General Public License along +// with this library; see the file COPYING3. If not see +// <http://www.gnu.org/licenses/>. + +#include <string> + +template<typename CT> + constexpr bool + test_move() + { + using char_type = typename CT::char_type; + char_type s1[3] = {1, 2, 3}; + CT::move(s1+1, s1, 2); + return s1[0]==char_type{1} && s1[1]==char_type{1} && s1[2]==char_type{2}; + } + +#ifndef __cpp_lib_constexpr_char_traits +# error Feature-test macro for constexpr char_traits is missing +#elif __cpp_lib_constexpr_char_traits != 201611 +# error Feature-test macro for constexpr char_traits has the wrong value +#endif + +static_assert( test_move<std::char_traits<char>>() ); +#ifdef _GLIBCXX_USE_WCHAR_T +static_assert( test_move<std::char_traits<wchar_t>>() ); +#endif +#ifdef _GLIBCXX_USE_CHAR8_T +static_assert( test_move<std::char_traits<char8_t>>() ); +#endif +static_assert( test_move<std::char_traits<char16_t>>() ); +static_assert( test_move<std::char_traits<char32_t>>() ); + +struct C { unsigned char c; }; +constexpr bool operator==(const C& c1, const C& c2) { return c1.c == c2.c; } +constexpr bool operator<(const C& c1, const C& c2) { return c1.c < c2.c; } +static_assert( test_move<std::char_traits<C>>() );
reply other threads:[~2020-06-15 20:16 UTC|newest] Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20200615201629.EB5D0388C02E@sourceware.org \ --to=iains@gcc.gnu.org \ --cc=gcc-cvs@gcc.gnu.org \ --cc=libstdc++-cvs@gcc.gnu.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).