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8d9254fc | 1 | // Copyright (C) 2018-2020 Free Software Foundation, Inc. |
f3e91052 JW |
2 | // |
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) | |
7 | // any later version. | |
8 | ||
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. | |
13 | ||
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/>. | |
17 | ||
f3e91052 JW |
18 | // { dg-options "-std=gnu++2a" } |
19 | // { dg-do compile { target c++2a } } | |
20 | ||
21 | #include <bit> | |
22 | ||
23 | template<typename UInt> | |
24 | constexpr auto | |
25 | test(UInt x) | |
26 | -> decltype(std::countr_one(x)) | |
27 | { | |
28 | static_assert( noexcept(std::countr_one(x)) ); | |
29 | ||
30 | constexpr unsigned digits = std::numeric_limits<UInt>::digits; | |
31 | ||
32 | static_assert( std::countr_one((UInt)0) == 0 ); | |
33 | static_assert( std::countr_one((UInt)-1) == digits ); | |
34 | static_assert( std::countr_one((UInt)127) == 7 ); | |
35 | ||
36 | static_assert( std::countr_one((UInt)1) == 1 ); | |
37 | static_assert( std::countr_one((UInt)3) == 2 ); | |
38 | static_assert( std::countr_one((UInt)0x1f) == 5 ); | |
39 | static_assert( std::countr_one((UInt)((UInt)-1 ^ 0x10)) == 4 ); | |
40 | ||
41 | if constexpr (std::numeric_limits<UInt>::digits > 8) | |
42 | { | |
43 | static_assert( std::countr_one((UInt)((UInt)-1 ^ 0x100)) == 8 ); | |
44 | static_assert( std::countr_one((UInt)((UInt)-1 ^ 0x101)) == 0 ); | |
45 | } | |
46 | ||
47 | if constexpr (std::numeric_limits<UInt>::digits > 64) | |
48 | { | |
49 | static_assert( std::countr_one((UInt)-1 ^ ((UInt)1 << 70)) == 70 ); | |
50 | } | |
51 | ||
52 | return true; | |
53 | } | |
54 | ||
55 | static_assert( test( (unsigned char)0 ) ); | |
56 | static_assert( test( (unsigned short)0 ) ); | |
57 | static_assert( test( (unsigned int)0 ) ); | |
58 | static_assert( test( (unsigned long)0 ) ); | |
59 | static_assert( test( (unsigned long long)0 ) ); | |
60 | ||
61 | // std::countr_one(T) shall not participate in overload resolution | |
62 | // unless T is an unsigned integer type. | |
63 | struct X { constexpr bool did_not_match() { return true; } }; | |
64 | constexpr X test(...) { return X{}; } | |
65 | static_assert( test( (bool)0 ).did_not_match() ); | |
66 | static_assert( test( (char)0 ).did_not_match() ); | |
67 | static_assert( test( (int)0 ).did_not_match() ); | |
68 | static_assert( test( (char16_t)0 ).did_not_match() ); | |
69 | static_assert( test( (float)0 ).did_not_match() ); | |
70 | static_assert( test( (void*)0 ).did_not_match() ); | |
71 | static_assert( test( X{} ).did_not_match() ); | |
72 | enum E : unsigned { e }; | |
73 | static_assert( test( e ).did_not_match() ); | |
74 | ||
f3e91052 JW |
75 | #if !defined(__STRICT_ANSI__) && defined _GLIBCXX_USE_INT128 |
76 | static_assert( test( (unsigned __int128)0 ) ); | |
77 | static_assert( test( (__int128)0 ).did_not_match() ); | |
78 | #endif | |
79 | #if defined(__GLIBCXX_TYPE_INT_N_0) | |
80 | static_assert( test( (unsigned __GLIBCXX_TYPE_INT_N_0)0 ) ); | |
81 | static_assert( test( (__GLIBCXX_TYPE_INT_N_0)0 ).did_not_match() ); | |
82 | #endif | |
83 | #if defined(__GLIBCXX_TYPE_INT_N_1) | |
84 | static_assert( test( (unsigned __GLIBCXX_TYPE_INT_N_1)0 ) ); | |
85 | static_assert( test( (__GLIBCXX_TYPE_INT_N_1)0 ).did_not_match() ); | |
86 | #endif | |
87 | #if defined(__GLIBCXX_TYPE_INT_N_2) | |
88 | static_assert( test( (unsigned __GLIBCXX_TYPE_INT_N_2)0 ) ); | |
89 | static_assert( test( (__GLIBCXX_TYPE_INT_N_2)0 ).did_not_match() ); | |
90 | #endif | |
47f79054 JW |
91 | |
92 | #include <cstddef> | |
93 | static_assert( test( (std::byte)0 ).did_not_match() ); |