libstdc++-v3/testsuite/26_numerics/saturation/mul.cc

   1 // { dg-do compile { target c++26 } }
   2
   3 // C++26 Saturation arithmetic [numerics.sat]
   4
   5 #include <numeric>
   6 #include <climits>
   7
   8 template<typename T, typename U>
   9 concept can_mul_sat
  10   = requires(T t, U u) { { std::mul_sat(t, u) } -> std::same_as<T>; };
  11
  12 static_assert( can_mul_sat<int, int> );
  13 static_assert( not can_mul_sat<int, short> );
  14 static_assert( not can_mul_sat<unsigned, int> );
  15 static_assert( noexcept(std::mul_sat(0, 0)) );
  16
  17 using std::mul_sat;
  18
  19 static_assert(mul_sat(1, 1) == 1);
  20 static_assert(mul_sat(10, 11) == 110);
  21 static_assert(mul_sat(INT_MAX / 2, 3) == INT_MAX);
  22 static_assert(mul_sat(INT_MAX / 2, -3) == INT_MIN);
  23 static_assert(mul_sat(INT_MAX / -2, 3) == INT_MIN);
  24 static_assert(mul_sat(INT_MIN / 2, -3) == INT_MAX);
  25 static_assert(mul_sat(INT_MIN, -1) == INT_MAX);
  26 static_assert(mul_sat(INT_MAX, -1) == INT_MIN + 1);
  27 static_assert(mul_sat(INT_MAX, INT_MAX) == INT_MAX);
  28 static_assert(mul_sat(INT_MAX, -INT_MAX) == INT_MIN);
  29 static_assert(mul_sat(UINT_MAX, UINT_MAX) == UINT_MAX);
  30 static_assert(mul_sat(UINT_MAX, 0u) == 0);
  31 static_assert(mul_sat(0u, UINT_MAX) == 0);
  32 static_assert(mul_sat((short)SHRT_MAX, (short)2) == SHRT_MAX);
  33 static_assert(mul_sat((short)SHRT_MAX, (short)SHRT_MIN) == SHRT_MIN);
  34 static_assert(mul_sat<long long>(SHRT_MAX, 2) == 2L * SHRT_MAX);