From e6e01618e83bcd9eb3a2b27df30ed87106a748b4 Mon Sep 17 00:00:00 2001 From: Jonathan Wakely Date: Wed, 19 Aug 2020 20:36:10 +0100 Subject: [PATCH] libstdc++: Make make-unsigned-like-t<__int128> work [PR 96042] As well as ensuring that numeric_limits<__int128> is defined, we need to ensure that make-unsigned-like-t and to-unsigned-like work correctly for 128-bit integers in strict mode. This ensures that a subrange created from an iota_view's iterator and sentinel can represent its size. Co-authored-by: Patrick Palka libstdc++-v3/ChangeLog: 2020-08-19 Jonathan Wakely Patrick Palka PR libstdc++/96042 * include/bits/range_access.h (__detail::__to_unsigned_like): Do not use make_unsigned_t in the return type, as it can result in an error before the integral constraint is checked. [__STRICT_ANSI__]: Add overloads for 128-bit integer types. (__detail::__make_unsigned_like_t): Define as the return type of __to_unsigned_like. * testsuite/std/ranges/subrange/96042.cc: New test. --- libstdc++-v3/include/bits/range_access.h | 18 +++++++--- .../testsuite/std/ranges/subrange/96042.cc | 34 +++++++++++++++++++ 2 files changed, 48 insertions(+), 4 deletions(-) create mode 100644 libstdc++-v3/testsuite/std/ranges/subrange/96042.cc diff --git a/libstdc++-v3/include/bits/range_access.h b/libstdc++-v3/include/bits/range_access.h index 3eb1f2fd272..bafced31ea8 100644 --- a/libstdc++-v3/include/bits/range_access.h +++ b/libstdc++-v3/include/bits/range_access.h @@ -364,13 +364,23 @@ namespace ranges { return __max_size_type(__t); } template - constexpr make_unsigned_t<_Tp> + constexpr auto __to_unsigned_like(_Tp __t) noexcept - { return __t; } + { return static_cast>(__t); } - template> +#if defined __STRICT_ANSI__ && defined __SIZEOF_INT128__ + constexpr unsigned __int128 + __to_unsigned_like(__int128 __t) noexcept + { return __t; } + + constexpr unsigned __int128 + __to_unsigned_like(unsigned __int128 __t) noexcept + { return __t; } +#endif + + template using __make_unsigned_like_t - = conditional_t<_MaxDiff, __max_size_type, make_unsigned_t<_Tp>>; + = decltype(__detail::__to_unsigned_like(std::declval<_Tp>())); // Part of the constraints of ranges::borrowed_range template diff --git a/libstdc++-v3/testsuite/std/ranges/subrange/96042.cc b/libstdc++-v3/testsuite/std/ranges/subrange/96042.cc new file mode 100644 index 00000000000..5826203f03c --- /dev/null +++ b/libstdc++-v3/testsuite/std/ranges/subrange/96042.cc @@ -0,0 +1,34 @@ +// Copyright (C) 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 +// . + +// { dg-options "-std=c++20" } +// { dg-do compile { target c++2a } } + +#include + +constexpr bool +test01() +{ + using I = unsigned long long; + // view with a difference type that doesn't fit in long long: + std::ranges::iota_view v(0, std::numeric_limits::max()); + // view with a size type that doesn't fit in unsigned long long: + std::ranges::subrange sr{v.begin(), v.end()}; + auto sz = std::ranges::size(sr); + return sz == std::numeric_limits::max(); +} +static_assert( test01() ); -- 2.30.2