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// Copyright (C) 2018-2022 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 UInt>
constexpr auto
test(UInt x)
-> decltype(std::countl_one(x))
{
static_assert( noexcept(std::countl_one(x)) );
constexpr unsigned digits = std::numeric_limits<UInt>::digits;
static_assert( std::countl_one((UInt)0) == 0 );
static_assert( std::countl_one((UInt)-1) == digits );
static_assert( std::countl_one((UInt)3) == 0 );
static_assert( std::countl_one((UInt)((UInt)1 << digits - 1)) == 1 );
static_assert( std::countl_one((UInt)((UInt)3 << digits - 2)) == 2 );
static_assert( std::countl_one((UInt)((UInt)7 << digits - 3)) == 3 );
static_assert( std::countl_one((UInt)((UInt)255 << digits - 8)) == 8 );
if constexpr (std::numeric_limits<UInt>::digits > 8)
{
static_assert( std::countl_one((UInt)((UInt)-1 ^ 0x100)) == digits - 9 );
static_assert( std::countl_one((UInt)((UInt)-1 ^ 0x101)) == digits - 9 );
static_assert( std::countl_one((UInt)((UInt)-1 ^ 0x201)) == digits - 10 );
}
if constexpr (std::numeric_limits<UInt>::digits > 64)
{
static_assert( std::countl_one((UInt)-1 ^ ((UInt)1 << 70)) == digits - 71 );
}
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::countl_one(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() );
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