================ @@ -0,0 +1,119 @@ +// -*- C++ -*- +//===----------------------------------------------------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +#ifndef _LIBCPP___NUMERIC_SATURATION_ARITHMETIC_H +#define _LIBCPP___NUMERIC_SATURATION_ARITHMETIC_H + +#include <__concepts/arithmetic.h> +#include <__config> +#include <__type_traits/decay.h> +#include <__utility/cmp.h> +#include <limits> + +#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) +# pragma GCC system_header +#endif + +_LIBCPP_BEGIN_NAMESPACE_STD + +#if _LIBCPP_STD_VER >= 26 + +template <typename _Tp> +concept __libcpp_standard_integer = __libcpp_unsigned_integer<decay_t<_Tp>> || __libcpp_signed_integer<decay_t<_Tp>>; + +template <__libcpp_standard_integer _Tp> +_LIBCPP_HIDE_FROM_ABI constexpr _Tp add_sat(_Tp __x, _Tp __y) noexcept { + if (_Tp __sum; !__builtin_add_overflow(__x, __y, &__sum)) + return __sum; + // Handle overflow + if constexpr (__libcpp_unsigned_integer<_Tp>) { + return std::numeric_limits<_Tp>::max(); + } else { + // Signed addition overflow + if (__x > 0) + // Overflows if (x > 0 && y > 0) + return std::numeric_limits<_Tp>::max(); + else + // Overflows if (x < 0 && y < 0) + return std::numeric_limits<_Tp>::min(); + } +} + +template <__libcpp_standard_integer _Tp> +_LIBCPP_HIDE_FROM_ABI constexpr _Tp sub_sat(_Tp __x, _Tp __y) noexcept { + if (_Tp __sub; !__builtin_sub_overflow(__x, __y, &__sub)) + return __sub; + // Handle overflow + if constexpr (__libcpp_unsigned_integer<_Tp>) { + // Overflows if (x < y) + return std::numeric_limits<_Tp>::min(); + } else { + // Signed subtration overflow + if (__x > 0) + // Overflows if (x > 0 && y < 0) + return std::numeric_limits<_Tp>::max(); + else + // Overflows if (x < 0 && y > 0) + return std::numeric_limits<_Tp>::min(); + } +} + +template <__libcpp_standard_integer _Tp> +_LIBCPP_HIDE_FROM_ABI constexpr _Tp mul_sat(_Tp __x, _Tp __y) noexcept { + if (_Tp __mul; !__builtin_mul_overflow(__x, __y, &__mul)) + return __mul; + // Handle overflow + if constexpr (__libcpp_unsigned_integer<_Tp>) { + return std::numeric_limits<_Tp>::max(); + } else { + // Signed multiplication overflow + if (__x > 0) { + if (__y > 0) + // Overflows if (x > 0 && y > 0) + return std::numeric_limits<_Tp>::max(); + // Overflows if (x > 0 && y < 0) + return std::numeric_limits<_Tp>::min(); + } + if (__y > 0) + // Overflows if (x < 0 && y > 0) + return std::numeric_limits<_Tp>::min(); + // Overflows if (x < 0 && y < 0) + return std::numeric_limits<_Tp>::max(); + } +} + +template <__libcpp_standard_integer _Tp> +_LIBCPP_HIDE_FROM_ABI constexpr _Tp div_sat(_Tp __x, _Tp __y) noexcept { + _LIBCPP_ASSERT_UNCATEGORIZED(__y != 0, "Division by 0 is undefined"); + if constexpr (__libcpp_unsigned_integer<_Tp>) { + return __x / __y; + } else { + // Handle signed division overflow + if (__x == std::numeric_limits<_Tp>::min() && __y == _Tp{-1}) + return std::numeric_limits<_Tp>::max(); + return __x / __y; + } +} + +template <__libcpp_standard_integer _Rp, __libcpp_standard_integer _Tp> +_LIBCPP_HIDE_FROM_ABI constexpr _Rp saturate_cast(_Tp __x) noexcept { ---------------- H-G-Hristov wrote:
OK. I'll remove the optimization for now. On optimized builds the difference according to my quick, stupid benchmark is near zero and on unoptimized builds less than 10%. https://quick-bench.com/q/QFdMFKaw_5OnmeDqB_BMkh0BaSg Please comment if you disagree. https://github.com/llvm/llvm-project/pull/77967 _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
