libcxx/test/std/numerics/bit/bitops.count/popcount.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is dual licensed under the MIT and the University of Illinois Open
   6 // Source Licenses. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 // UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
  10
  11 // template <class T>
  12 //   constexpr int popcount(T x) noexcept;
  13
  14 // Returns: The number of bits set to one in the value of x.
  15 //
  16 // Remarks: This function shall not participate in overload resolution unless
  17 //      T is an unsigned integer type
  18
  19 #include <bit>
  20 #include <cstdint>
  21 #include <type_traits>
  22 #include <cassert>
  23
  24 #include "test_macros.h"
  25
  26 class A{};
  27 enum       E1 : unsigned char { rEd };
  28 enum class E2 : unsigned char { red };
  29
  30 template <typename T>
  31 constexpr bool constexpr_test()
  32 {
  33         return std::popcount(T(0)) == 0
  34            &&  std::popcount(T(1)) == 1
  35            &&  std::popcount(T(2)) == 1
  36            &&  std::popcount(T(3)) == 2
  37            &&  std::popcount(T(4)) == 1
  38            &&  std::popcount(T(5)) == 2
  39            &&  std::popcount(T(6)) == 2
  40            &&  std::popcount(T(7)) == 3
  41            &&  std::popcount(T(8)) == 1
  42            &&  std::popcount(T(9)) == 2
  43            &&  std::popcount(std::numeric_limits<T>::max()) == std::numeric_limits<T>::digits
  44           ;
  45 }
  46
  47
  48 template <typename T>
  49 void runtime_test()
  50 {
  51         ASSERT_SAME_TYPE(int, decltype(std::popcount(T(0))));
  52         ASSERT_NOEXCEPT(               std::popcount(T(0)));
  53
  54         assert( std::popcount(T(121)) == 5);
  55         assert( std::popcount(T(122)) == 5);
  56         assert( std::popcount(T(123)) == 6);
  57         assert( std::popcount(T(124)) == 5);
  58         assert( std::popcount(T(125)) == 6);
  59         assert( std::popcount(T(126)) == 6);
  60         assert( std::popcount(T(127)) == 7);
  61         assert( std::popcount(T(128)) == 1);
  62         assert( std::popcount(T(129)) == 2);
  63         assert( std::popcount(T(130)) == 2);
  64 }
  65
  66 int main()
  67 {
  68
  69     {
  70     auto lambda = [](auto x) -> decltype(std::popcount(x)) {};
  71     using L = decltype(lambda);
  72
  73     static_assert( std::is_invocable_v<L, unsigned char>, "");
  74     static_assert( std::is_invocable_v<L, unsigned int>, "");
  75     static_assert( std::is_invocable_v<L, unsigned long>, "");
  76     static_assert( std::is_invocable_v<L, unsigned long long>, "");
  77
  78     static_assert( std::is_invocable_v<L, uint8_t>, "");
  79     static_assert( std::is_invocable_v<L, uint16_t>, "");
  80     static_assert( std::is_invocable_v<L, uint32_t>, "");
  81     static_assert( std::is_invocable_v<L, uint64_t>, "");
  82     static_assert( std::is_invocable_v<L, size_t>, "");
  83
  84     static_assert( std::is_invocable_v<L, uintmax_t>, "");
  85     static_assert( std::is_invocable_v<L, uintptr_t>, "");
  86
  87
  88     static_assert(!std::is_invocable_v<L, int>, "");
  89     static_assert(!std::is_invocable_v<L, signed int>, "");
  90     static_assert(!std::is_invocable_v<L, long>, "");
  91     static_assert(!std::is_invocable_v<L, long long>, "");
  92
  93     static_assert(!std::is_invocable_v<L, int8_t>, "");
  94     static_assert(!std::is_invocable_v<L, int16_t>, "");
  95     static_assert(!std::is_invocable_v<L, int32_t>, "");
  96     static_assert(!std::is_invocable_v<L, int64_t>, "");
  97     static_assert(!std::is_invocable_v<L, ptrdiff_t>, "");
  98
  99     static_assert(!std::is_invocable_v<L, bool>, "");
 100     static_assert(!std::is_invocable_v<L, signed char>, "");
 101     static_assert(!std::is_invocable_v<L, char16_t>, "");
 102     static_assert(!std::is_invocable_v<L, char32_t>, "");
 103
 104 #ifndef _LIBCPP_HAS_NO_INT128
 105     static_assert( std::is_invocable_v<L, __uint128_t>, "");
 106     static_assert(!std::is_invocable_v<L, __int128_t>, "");
 107 #endif
 108
 109     static_assert(!std::is_invocable_v<L, A>, "");
 110     static_assert(!std::is_invocable_v<L, E1>, "");
 111     static_assert(!std::is_invocable_v<L, E2>, "");
 112     }
 113
 114         static_assert(constexpr_test<unsigned char>(),      "");
 115         static_assert(constexpr_test<unsigned short>(),     "");
 116         static_assert(constexpr_test<unsigned>(),           "");
 117         static_assert(constexpr_test<unsigned long>(),      "");
 118         static_assert(constexpr_test<unsigned long long>(), "");
 119
 120         static_assert(constexpr_test<uint8_t>(),   "");
 121         static_assert(constexpr_test<uint16_t>(),  "");
 122         static_assert(constexpr_test<uint32_t>(),  "");
 123         static_assert(constexpr_test<uint64_t>(),  "");
 124         static_assert(constexpr_test<size_t>(),    "");
 125         static_assert(constexpr_test<uintmax_t>(), "");
 126         static_assert(constexpr_test<uintptr_t>(), "");
 127
 128 #ifndef _LIBCPP_HAS_NO_INT128
 129         static_assert(constexpr_test<__uint128_t>(),        "");
 130 #endif
 131
 132
 133         runtime_test<unsigned char>();
 134         runtime_test<unsigned>();
 135         runtime_test<unsigned short>();
 136         runtime_test<unsigned long>();
 137         runtime_test<unsigned long long>();
 138
 139         runtime_test<uint8_t>();
 140         runtime_test<uint16_t>();
 141         runtime_test<uint32_t>();
 142         runtime_test<uint64_t>();
 143         runtime_test<size_t>();
 144         runtime_test<uintmax_t>();
 145         runtime_test<uintptr_t>();
 146
 147 #ifndef _LIBCPP_HAS_NO_INT128
 148         runtime_test<__uint128_t>();
 149
 150         {
 151         __uint128_t val = 128;
 152
 153         val <<= 32;
 154         assert( std::popcount(val-1) == 39);
 155         assert( std::popcount(val)   ==  1);
 156         assert( std::popcount(val+1) ==  2);
 157         val <<= 2;
 158         assert( std::popcount(val-1) == 41);
 159         assert( std::popcount(val)   ==  1);
 160         assert( std::popcount(val+1) ==  2);
 161         val <<= 3;
 162         assert( std::popcount(val-1) == 44);
 163         assert( std::popcount(val)   ==  1);
 164         assert( std::popcount(val+1) ==  2);
 165         }
 166 #endif
 167 }