diff options
| -rw-r--r-- | libstdc++-v3/ChangeLog | 6 | ||||
| -rw-r--r-- | libstdc++-v3/include/std/bit | 10 | ||||
| -rw-r--r-- | libstdc++-v3/testsuite/26_numerics/bit/bitops.count/popcount.cc | 108 |
3 files changed, 117 insertions, 7 deletions
diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index f6c39b6..e3211bc 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,3 +1,9 @@ +2018-07-04 Jonathan Wakely <jwakely@redhat.com> + + * include/std/bit (__rotl, __rotr): Avoid branch. + (_If_is_unsigned_integer): Use remove_cv_t. + * testsuite/26_numerics/bit/bitops.count/popcount.cc: New. + 2018-07-03 Jonathan Wakely <jwakely@redhat.com> P0556R3 Integral power-of-2 operations, P0553R2 Bit operations diff --git a/libstdc++-v3/include/std/bit b/libstdc++-v3/include/std/bit index 76aa095..ace8895 100644 --- a/libstdc++-v3/include/std/bit +++ b/libstdc++-v3/include/std/bit @@ -46,9 +46,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION { constexpr auto _Nd = numeric_limits<_Tp>::digits; const unsigned __sN = __s % _Nd; - if (__sN) - return (__x << __sN) | (__x >> (_Nd - __sN)); - return __x; + return (__x << __sN) | (__x >> ((-__sN) % _Nd)); } template<typename _Tp> @@ -57,9 +55,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION { constexpr auto _Nd = numeric_limits<_Tp>::digits; const unsigned __sN = __s % _Nd; - if (__sN) - return (__x >> __sN) | (__x << (_Nd - __sN)); - return __x; + return (__x >> __sN) | (__x << ((-__sN) % _Nd)); } template<typename _Tp> @@ -237,7 +233,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION template<typename _Tp, typename _Up = _Tp> using _If_is_unsigned_integer - = typename _If_is_unsigned_integer_type<_Tp, _Up>::type; + = typename _If_is_unsigned_integer_type<remove_cv_t<_Tp>, _Up>::type; #if ! __STRICT_ANSI__ // [bitops.rot], rotating diff --git a/libstdc++-v3/testsuite/26_numerics/bit/bitops.count/popcount.cc b/libstdc++-v3/testsuite/26_numerics/bit/bitops.count/popcount.cc new file mode 100644 index 0000000..2982cb1 --- /dev/null +++ b/libstdc++-v3/testsuite/26_numerics/bit/bitops.count/popcount.cc @@ -0,0 +1,108 @@ +// Copyright (C) 2018 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-do run { target c++11 } } + +// { dg-options "-std=gnu++2a" } +// { dg-do compile { target c++2a } } + +#include <bit> + +template<typename UInt> +constexpr auto +test(UInt x) +-> decltype(std::popcount(x)) +{ + static_assert( noexcept(std::popcount(x)) ); + + constexpr unsigned digits = std::numeric_limits<UInt>::digits; + + static_assert( std::popcount((UInt)0) == 0 ); + static_assert( std::popcount((UInt)-1) == digits ); + static_assert( std::popcount((UInt)-2) == digits - 1 ); + static_assert( std::popcount((UInt)127) == 7 ); + + static_assert( std::popcount((UInt)1) == 1 ); + static_assert( std::popcount((UInt)2) == 1 ); + static_assert( std::popcount((UInt)0x70) == 3 ); + + if constexpr (std::numeric_limits<UInt>::digits > 8) + { + static_assert( std::popcount((UInt)(0x101)) == 2 ); + static_assert( std::popcount((UInt)(0xfff)) == 12 ); + } + + if constexpr (std::numeric_limits<UInt>::digits > 64) + { + static_assert( std::popcount((UInt)0xffffffffffffffff) == 64 ); + static_assert( std::popcount(0x5555555555555555 | ((UInt)1 << 64)) == 33 ); + static_assert( std::popcount(0x5555555555555555 | ((UInt)3 << 64)) == 34 ); + } + + 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::popcount(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() ); + +#ifndef __STRICT_ANSI__ +#include <cstddef> +static_assert( std::popcount(std::byte{0x00}) == 0 ); +static_assert( std::popcount(std::byte{0x01}) == 1 ); +static_assert( std::popcount(std::byte{0x02}) == 1 ); +static_assert( std::popcount(std::byte{0x03}) == 2 ); +static_assert( std::popcount(std::byte{0x30}) == 2 ); +static_assert( std::popcount(std::byte{0x40}) == 1 ); +static_assert( std::popcount(std::byte{0x41}) == 2 ); +static_assert( std::popcount(std::byte{0xff}) == 8 ); +#else +static_assert( test( (std::byte)0 ).did_not_match() ); +#endif + +#if !defined(__STRICT_ANSI__) && defined _GLIBCXX_USE_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 |