568eb2d25c
This was approved for C++26 last week at the WG21 meeting in Kona. libstdc++-v3/ChangeLog: * include/Makefile.am: Add new header. * include/Makefile.in: Regenerate. * include/bits/version.def (saturation_arithmetic): Define. * include/bits/version.h: Regenerate. * include/std/numeric: Include new header. * include/bits/sat_arith.h: New file. * testsuite/26_numerics/saturation/add.cc: New test. * testsuite/26_numerics/saturation/cast.cc: New test. * testsuite/26_numerics/saturation/div.cc: New test. * testsuite/26_numerics/saturation/mul.cc: New test. * testsuite/26_numerics/saturation/sub.cc: New test. * testsuite/26_numerics/saturation/version.cc: New test.
73 lines
2.8 KiB
C++
73 lines
2.8 KiB
C++
// { dg-do compile { target c++26 } }
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// C++26 Saturation arithmetic [numerics.sat]
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#include <numeric>
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#include <limits>
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template<typename T, typename U>
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concept can_add_sat
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= requires(T t, U u) { { std::add_sat(t, u) } -> std::same_as<T>; };
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static_assert( can_add_sat<int, int> );
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static_assert( not can_add_sat<int, short> );
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static_assert( not can_add_sat<unsigned, int> );
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static_assert( noexcept(std::add_sat(0, 0)) );
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using std::add_sat;
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// Signed type
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static_assert(add_sat(0, 0) == 0);
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static_assert(add_sat(1, 1) == 2);
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static_assert(add_sat(-1, -1) == -2);
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static_assert(add_sat(-1, 1) == 0);
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constexpr auto max = std::numeric_limits<int>::max();
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constexpr auto min = std::numeric_limits<int>::min();
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static_assert(add_sat(max, 1) == max);
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static_assert(add_sat(1, max) == max);
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static_assert(add_sat(max, max) == max);
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static_assert(add_sat(min, -1) == min);
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static_assert(add_sat(-1, min) == min);
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static_assert(add_sat(min, min) == min);
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static_assert(add_sat(max, min) == -1);
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static_assert(add_sat(min, max) == -1);
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// Wider signed type than the args
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static_assert(add_sat<long long>(max, max) == (long long)max * 2);
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static_assert(add_sat<long long>(min, min) == (long long)min * 2);
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// Signed type that undergoes integer promotion
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constexpr auto shrt_max = std::numeric_limits<short>::max();
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constexpr auto shrt_min = std::numeric_limits<short>::min();
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static_assert(add_sat<short>(0, 0) == 0);
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static_assert(add_sat<short>(1, 1) == 2);
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static_assert(add_sat<short>(shrt_max, shrt_max) == shrt_max);
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static_assert(add_sat<short>(shrt_max, 1) == shrt_max);
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static_assert(add_sat<short>(1, shrt_max) == shrt_max);
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static_assert(add_sat<short>(shrt_min, (short)-1) == shrt_min);
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static_assert(add_sat<short>((short)-1, shrt_min) == shrt_min);
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static_assert(add_sat<short>(shrt_min, (short)1) == -shrt_max);
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static_assert(add_sat<short>((short)1, shrt_min) == -shrt_max);
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// Unsigned type
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static_assert(add_sat(0u, 0u) == 0u);
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static_assert(add_sat(1u, 1u) == 2u);
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constexpr auto umax = std::numeric_limits<unsigned>::max();
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static_assert(add_sat(umax, 1u) == umax);
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static_assert(add_sat(1u, umax) == umax);
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static_assert(add_sat(umax, umax) == umax);
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static_assert(add_sat(0u, umax) == umax);
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static_assert(add_sat(umax, 0u) == umax);
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static_assert(add_sat(0u, 1u) == 1u);
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static_assert(add_sat(1u, 0u) == 1u);
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// Wider unsigned type than the args
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static_assert(add_sat<unsigned long long>(umax, umax) == (long long)umax * 2);
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// Unsigned type that undergoes integer promotion
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constexpr auto ushrt_max = std::numeric_limits<unsigned short>::max();
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static_assert(add_sat<unsigned short>(0, 0) == 0);
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static_assert(add_sat<unsigned short>(1, 1) == 2);
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static_assert(add_sat<unsigned short>(ushrt_max, ushrt_max) == ushrt_max);
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static_assert(add_sat<unsigned short>(ushrt_max, 1) == ushrt_max);
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static_assert(add_sat<unsigned short>(1, ushrt_max) == ushrt_max);
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