]>
git.ipfire.org Git - thirdparty/gcc.git/blob - libstdc++-v3/testsuite/26_numerics/bit/bit.count/countr_one.cc
1 // Copyright (C) 2018-2021 Free Software Foundation, Inc.
3 // This file is part of the GNU ISO C++ Library. This library is free
4 // software; you can redistribute it and/or modify it under the
5 // terms of the GNU General Public License as published by the
6 // Free Software Foundation; either version 3, or (at your option)
9 // This library is distributed in the hope that it will be useful,
10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 // GNU General Public License for more details.
14 // You should have received a copy of the GNU General Public License along
15 // with this library; see the file COPYING3. If not see
16 // <http://www.gnu.org/licenses/>.
18 // { dg-options "-std=gnu++2a" }
19 // { dg-do compile { target c++2a } }
24 template<typename UInt
>
27 -> decltype(std::countr_one(x
))
29 static_assert( noexcept(std::countr_one(x
)) );
31 constexpr unsigned digits
= std::numeric_limits
<UInt
>::digits
;
33 static_assert( std::countr_one((UInt
)0) == 0 );
34 static_assert( std::countr_one((UInt
)-1) == digits
);
35 static_assert( std::countr_one((UInt
)127) == 7 );
37 static_assert( std::countr_one((UInt
)1) == 1 );
38 static_assert( std::countr_one((UInt
)3) == 2 );
39 static_assert( std::countr_one((UInt
)0x1f) == 5 );
40 static_assert( std::countr_one((UInt
)((UInt
)-1 ^ 0x10)) == 4 );
42 if constexpr (std::numeric_limits
<UInt
>::digits
> 8)
44 static_assert( std::countr_one((UInt
)((UInt
)-1 ^ 0x100)) == 8 );
45 static_assert( std::countr_one((UInt
)((UInt
)-1 ^ 0x101)) == 0 );
48 if constexpr (std::numeric_limits
<UInt
>::digits
> 64)
50 static_assert( std::countr_one((UInt
)-1 ^ ((UInt
)1 << 70)) == 70 );
56 static_assert( test( (unsigned char)0 ) );
57 static_assert( test( (unsigned short)0 ) );
58 static_assert( test( (unsigned int)0 ) );
59 static_assert( test( (unsigned long)0 ) );
60 static_assert( test( (unsigned long long)0 ) );
62 // std::countr_one(T) shall not participate in overload resolution
63 // unless T is an unsigned integer type.
64 struct X
{ constexpr bool did_not_match() { return true; } };
65 constexpr X
test(...) { return X
{}; }
66 static_assert( test( (bool)0 ).did_not_match() );
67 static_assert( test( (char)0 ).did_not_match() );
68 static_assert( test( (int)0 ).did_not_match() );
69 static_assert( test( (char16_t
)0 ).did_not_match() );
70 static_assert( test( (float)0 ).did_not_match() );
71 static_assert( test( (void*)0 ).did_not_match() );
72 static_assert( test( X
{} ).did_not_match() );
73 enum E
: unsigned { e
};
74 static_assert( test( e
).did_not_match() );
76 #if !defined(__STRICT_ANSI__) && defined _GLIBCXX_USE_INT128
77 static_assert( test( (unsigned __int128
)0 ) );
78 static_assert( test( (__int128
)0 ).did_not_match() );
80 #if defined(__GLIBCXX_TYPE_INT_N_0)
81 static_assert( test( (unsigned __GLIBCXX_TYPE_INT_N_0
)0 ) );
82 static_assert( test( (__GLIBCXX_TYPE_INT_N_0
)0 ).did_not_match() );
84 #if defined(__GLIBCXX_TYPE_INT_N_1)
85 static_assert( test( (unsigned __GLIBCXX_TYPE_INT_N_1
)0 ) );
86 static_assert( test( (__GLIBCXX_TYPE_INT_N_1
)0 ).did_not_match() );
88 #if defined(__GLIBCXX_TYPE_INT_N_2)
89 static_assert( test( (unsigned __GLIBCXX_TYPE_INT_N_2
)0 ) );
90 static_assert( test( (__GLIBCXX_TYPE_INT_N_2
)0 ).did_not_match() );
94 static_assert( test( (std::byte
)0 ).did_not_match() );