| // Copyright (C) 2018-2023 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=gnu++2a" } |
| // { dg-do compile { target c++2a } } |
| |
| #include <bit> |
| #include <limits> |
| |
| template<typename T> |
| constexpr T max = std::numeric_limits<T>::max(); |
| // Largest representable power of two (i.e. has most significant bit set) |
| template<typename T> |
| constexpr T maxpow2 = T(1) << (std::numeric_limits<T>::digits - 1); |
| |
| // Detect whether std::bit_ceil(N) is a constant expression. |
| template<auto N, typename = void> |
| struct bit_ceil_valid |
| : std::false_type { }; |
| |
| template<auto N> |
| struct bit_ceil_valid<N, std::void_t<char[(std::bit_ceil(N), 1)]>> |
| : std::true_type { }; |
| |
| template<typename UInt> |
| constexpr auto |
| test(UInt x) |
| -> decltype(std::bit_ceil(x)) |
| { |
| static_assert( noexcept(std::bit_ceil(x)) ); |
| |
| static_assert( std::bit_ceil(UInt(0)) == 1 ); |
| static_assert( std::bit_ceil(UInt(1)) == 1 ); |
| static_assert( std::bit_ceil(UInt(2)) == 2 ); |
| static_assert( std::bit_ceil(UInt(3)) == 4 ); |
| static_assert( std::bit_ceil(UInt(4)) == 4 ); |
| static_assert( std::bit_ceil(UInt(0x11)) == 0x20 ); |
| static_assert( std::bit_ceil(UInt(0x20)) == 0x20 ); |
| |
| if constexpr (std::numeric_limits<UInt>::digits > 8) |
| { |
| static_assert( std::bit_ceil(UInt(0x201)) == 0x400 ); |
| static_assert( std::bit_ceil(UInt(0x8ff)) == 0x1000 ); |
| static_assert( std::bit_ceil(UInt(0x1000)) == 0x1000 ); |
| } |
| |
| if constexpr (std::numeric_limits<UInt>::digits > 32) |
| { |
| static_assert( std::bit_ceil(UInt(0xabcdef)) == 0x1000000 ); |
| static_assert( std::bit_ceil(UInt(0x1000000)) == 0x1000000 ); |
| static_assert( std::bit_ceil(UInt(0x1000001)) == 0x2000000 ); |
| } |
| |
| if constexpr (std::numeric_limits<UInt>::digits > 64) |
| { |
| static_assert( std::bit_ceil(UInt(1) << 64) == (UInt(1) << 64) ); |
| static_assert( std::bit_ceil(UInt(3) << 64) == (UInt(4) << 64) ); |
| } |
| |
| constexpr UInt msb = maxpow2<UInt>; |
| static_assert( bit_ceil_valid<msb>() ); |
| static_assert( std::bit_ceil( msb ) == msb ); |
| static_assert( std::bit_ceil( UInt(msb - 1) ) == msb ); |
| static_assert( std::bit_ceil( UInt(msb - 2) ) == msb ); |
| static_assert( std::bit_ceil( UInt(msb - 3) ) == msb ); |
| |
| // P1355R2: not a constant expression if the result is not representable |
| static_assert( !bit_ceil_valid<UInt(msb + 1)>() ); |
| static_assert( !bit_ceil_valid<max<UInt>>() ); |
| static_assert( !bit_ceil_valid<UInt(max<UInt> - 1)>() ); |
| static_assert( !bit_ceil_valid<UInt(max<UInt> - 2)>() ); |
| |
| return true; |
| } |
| |
| static_assert( test( (unsigned char)0 ) ); |
| static_assert( test( (unsigned short)0 ) ); |
| static_assert( test( (unsigned int)0 ) ); |
| static_assert( test( (unsigned long)0 ) ); |
| static_assert( test( (unsigned long long)0 ) ); |
| |
| // std::bit_ceil(T) shall not participate in overload resolution |
| // unless T is an unsigned integer type. |
| struct X { constexpr bool did_not_match() { return true; } }; |
| constexpr X test(...) { return X{}; } |
| static_assert( test( (bool)0 ).did_not_match() ); |
| static_assert( test( (char)0 ).did_not_match() ); |
| static_assert( test( (int)0 ).did_not_match() ); |
| static_assert( test( (char16_t)0 ).did_not_match() ); |
| static_assert( test( (float)0 ).did_not_match() ); |
| static_assert( test( (void*)0 ).did_not_match() ); |
| static_assert( test( X{} ).did_not_match() ); |
| enum E : unsigned { e }; |
| static_assert( test( e ).did_not_match() ); |
| |
| #if !defined(__STRICT_ANSI__) && defined __SIZEOF_INT128__ |
| static_assert( test( (unsigned __int128)0 ) ); |
| static_assert( test( (__int128)0 ).did_not_match() ); |
| #endif |
| #if defined(__GLIBCXX_TYPE_INT_N_0) |
| static_assert( test( (unsigned __GLIBCXX_TYPE_INT_N_0)0 ) ); |
| static_assert( test( (__GLIBCXX_TYPE_INT_N_0)0 ).did_not_match() ); |
| #endif |
| #if defined(__GLIBCXX_TYPE_INT_N_1) |
| static_assert( test( (unsigned __GLIBCXX_TYPE_INT_N_1)0 ) ); |
| static_assert( test( (__GLIBCXX_TYPE_INT_N_1)0 ).did_not_match() ); |
| #endif |
| #if defined(__GLIBCXX_TYPE_INT_N_2) |
| static_assert( test( (unsigned __GLIBCXX_TYPE_INT_N_2)0 ) ); |
| static_assert( test( (__GLIBCXX_TYPE_INT_N_2)0 ).did_not_match() ); |
| #endif |
| #if defined(__GLIBCXX_TYPE_INT_N_3) |
| static_assert( test( (unsigned __GLIBCXX_TYPE_INT_N_3)0 ) ); |
| static_assert( test( (__GLIBCXX_TYPE_INT_N_3)0 ).did_not_match() ); |
| #endif |
| |
| #include <cstddef> |
| static_assert( test( (std::byte)0 ).did_not_match() ); |