libcxx/test/std/numerics/numeric.ops/numeric.ops.sat/sub_sat.compile.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20, c++23
  10
  11 // <numeric>
  12
  13 // template<class T>
  14 // constexpr T sub_sat(T x, T y) noexcept;                     // freestanding
  15
  16 #include <concepts>
  17 #include <numeric>
  18
  19 #include "test_macros.h"
  20
  21 template <typename T, typename U>
  22 concept CanDo = requires(T x, U y) {
  23   { std::sub_sat(x, y) } -> std::same_as<T>;
  24 };
  25
  26 template <typename T, typename U>
  27 constexpr void test_constraint_success() {
  28   static_assert(CanDo<T, T>);
  29   static_assert(!CanDo<U, T>);
  30   static_assert(!CanDo<T, U>);
  31 }
  32
  33 template <typename T>
  34 constexpr void test_constraint_fail() {
  35   using I = int;
  36   static_assert(!CanDo<T, T>);
  37   static_assert(!CanDo<I, T>);
  38   static_assert(!CanDo<T, I>);
  39 }
  40
  41 constexpr void test() {
  42   // Contraint success - Signed
  43   using SI = long long int;
  44   test_constraint_success<signed char, SI>();
  45   test_constraint_success<short int, SI>();
  46   test_constraint_success<signed char, SI>();
  47   test_constraint_success<short int, SI>();
  48   test_constraint_success<int, SI>();
  49   test_constraint_success<long int, SI>();
  50   test_constraint_success<long long int, int>();
  51 #ifndef TEST_HAS_NO_INT128
  52   test_constraint_success<__int128_t, SI>();
  53 #endif
  54   // Contraint success - Unsigned
  55   using UI = unsigned long long int;
  56   test_constraint_success<unsigned char, UI>();
  57   test_constraint_success<unsigned short int, UI>();
  58   test_constraint_success<unsigned int, UI>();
  59   test_constraint_success<unsigned long int, UI>();
  60   test_constraint_success<unsigned long long int, unsigned int>();
  61 #ifndef TEST_HAS_NO_INT128
  62   test_constraint_success<__uint128_t, UI>();
  63 #endif
  64
  65   // Contraint failure
  66   test_constraint_fail<bool>();
  67   test_constraint_fail<char>();
  68 #ifndef TEST_HAS_NO_INT128
  69   test_constraint_fail<wchar_t>();
  70 #endif
  71   test_constraint_fail<char8_t>();
  72   test_constraint_fail<char16_t>();
  73   test_constraint_fail<char32_t>();
  74   test_constraint_fail<float>();
  75   test_constraint_fail<double>();
  76   test_constraint_fail<long double>();
  77 }