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From: Nathan Sidwell <nathan@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org, libstdc++-cvs@gcc.gnu.org Subject: [gcc/devel/c++-modules] libstdc++: Make __int128 meet integer-class requirements [PR 96042] Date: Fri, 28 Aug 2020 15:56:38 +0000 (GMT) [thread overview] Message-ID: <20200828155638.8FBE73947C3B@sourceware.org> (raw) https://gcc.gnu.org/g:386fd16c551188e20d5b1684b7139e4269f9a739 commit 386fd16c551188e20d5b1684b7139e4269f9a739 Author: Jonathan Wakely <jwakely@redhat.com> Date: Wed Aug 19 16:27:25 2020 +0100 libstdc++: Make __int128 meet integer-class requirements [PR 96042] Because __int128 can be used as the difference type for iota_view, we need to ensure that it meets the requirements of an integer-class type. The requirements in [iterator.concept.winc] p10 include numeric_limits being specialized and giving meaningful answers. Currently we only specialize numeric_limits for non-standard integer types in non-strict modes. However, nothing prevents us from defining an explicit specialization for any implementation-defined type, so it doesn't matter whether std::is_integral<__int128> is true or not. This patch ensures that the numeric_limits specializations for signed and unsigned __int128 are defined whenever __int128 is available. It also makes the __numeric_traits and __int_limits helpers work for __int128, via a new __gnu_cxx::__is_integer_nonstrict trait. libstdc++-v3/ChangeLog: PR libstdc++/96042 * include/ext/numeric_traits.h (__is_integer_nonstrict): New trait which is true for 128-bit integers even in strict modes. (__numeric_traits_integer, __numeric_traits): Use __is_integer_nonstrict instead of __is_integer. * include/std/limits [__STRICT_ANSI__ && __SIZEOF_INT128__] (numeric_limits<__int128>, (numeric_limits<unsigned __int128>): Define. * testsuite/std/ranges/iota/96042.cc: New test. Diff: --- libstdc++-v3/include/ext/numeric_traits.h | 18 ++++++++++-- libstdc++-v3/include/std/limits | 10 +++++-- libstdc++-v3/testsuite/std/ranges/iota/96042.cc | 39 +++++++++++++++++++++++++ 3 files changed, 62 insertions(+), 5 deletions(-) diff --git a/libstdc++-v3/include/ext/numeric_traits.h b/libstdc++-v3/include/ext/numeric_traits.h index 69f286d7be7..585ecc0ba9f 100644 --- a/libstdc++-v3/include/ext/numeric_traits.h +++ b/libstdc++-v3/include/ext/numeric_traits.h @@ -51,11 +51,25 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION (__glibcxx_signed(_Tp) ? \ (((((_Tp)1 << (__glibcxx_digits(_Tp) - 1)) - 1) << 1) + 1) : ~(_Tp)0) + template<typename _Tp> + struct __is_integer_nonstrict + : public std::__is_integer<_Tp> + { }; + +#if defined __STRICT_ANSI__ && defined __SIZEOF_INT128__ + // __is_integer<__int128> is false, but we still want to allow it here. + template<> struct __is_integer_nonstrict<__int128> + { enum { __value = 1 }; typedef std::__true_type __type; }; + + template<> struct __is_integer_nonstrict<unsigned __int128> + { enum { __value = 1 }; typedef std::__true_type __type; }; +#endif + template<typename _Value> struct __numeric_traits_integer { #if __cplusplus >= 201103L - static_assert(std::__is_integer<_Value>::__value, + static_assert(__is_integer_nonstrict<_Value>::__value, "invalid specialization"); #endif @@ -132,7 +146,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION template<typename _Value> struct __numeric_traits - : public __conditional_type<std::__is_integer<_Value>::__value, + : public __conditional_type<__is_integer_nonstrict<_Value>::__value, __numeric_traits_integer<_Value>, __numeric_traits_floating<_Value> >::__type { }; diff --git a/libstdc++-v3/include/std/limits b/libstdc++-v3/include/std/limits index f5e403be727..20883ba6403 100644 --- a/libstdc++-v3/include/std/limits +++ b/libstdc++-v3/include/std/limits @@ -1477,8 +1477,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION = round_toward_zero; }; -#if !defined(__STRICT_ANSI__) - #define __INT_N(TYPE, BITSIZE, EXT, UEXT) \ template<> \ struct numeric_limits<TYPE> \ @@ -1632,6 +1630,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION #define __INT_N_U201103(TYPE) #endif +#if !defined(__STRICT_ANSI__) #ifdef __GLIBCXX_TYPE_INT_N_0 __INT_N(__GLIBCXX_TYPE_INT_N_0, __GLIBCXX_BITSIZE_INT_N_0, __INT_N_201103 (__GLIBCXX_TYPE_INT_N_0), @@ -1653,11 +1652,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION __INT_N_U201103 (__GLIBCXX_TYPE_INT_N_3)) #endif +#elif defined __STRICT_ANSI__ && defined __SIZEOF_INT128__ + __INT_N(__int128, 128, + __INT_N_201103 (__int128), + __INT_N_U201103 (__int128)) +#endif + #undef __INT_N #undef __INT_N_201103 #undef __INT_N_U201103 -#endif /// numeric_limits<float> specialization. template<> diff --git a/libstdc++-v3/testsuite/std/ranges/iota/96042.cc b/libstdc++-v3/testsuite/std/ranges/iota/96042.cc new file mode 100644 index 00000000000..6f5c8f61fd2 --- /dev/null +++ b/libstdc++-v3/testsuite/std/ranges/iota/96042.cc @@ -0,0 +1,39 @@ +// 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 +// <http://www.gnu.org/licenses/>. + +// { dg-options "-std=c++2a" } +// { dg-do compile { target c++2a } } + +#include <ranges> + +void +test01() +{ + // PR libstdc++/96042 + using V = std::ranges::iota_view<long long, int>; + using D = std::ranges::range_difference_t<V>; + using L = std::numeric_limits<D>; + static_assert( L::is_specialized ); + static_assert( L::is_signed ); + static_assert( L::is_integer ); + static_assert( L::is_exact ); + static_assert( L::digits > std::numeric_limits<long long>::digits ); + static_assert( L::digits10 == static_cast<int>(L::digits * 0.30103) ); + static_assert( L::min() == (D(1) << L::digits) ); + static_assert( L::max() == ~L::min() ); + static_assert( L::lowest() == L::min() ); +}
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