projects / thirdparty / gcc.git / blame
| Commit | Line | Data |
|---|---|---|
| a945c346 | 1 | // Copyright (C) 2020-2024 Free Software Foundation, Inc. |
| 02e32295 MK |
2 | // |
| 3 | // This file is part of the GNU ISO C++ Library. This library is free | |
| 4 | // software; you can redistribute it and/or modify it under the | |
| 5 | // terms of the GNU General Public License as published by the | |
| 6 | // Free Software Foundation; either version 3, or (at your option) | |
| 7 | // any later version. | |
| 8 | // | |
| 9 | // This library is distributed in the hope that it will be useful, | |
| 10 | // but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 11 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 12 | // GNU General Public License for more details. | |
| 13 | // | |
| 14 | // You should have received a copy of the GNU General Public License along | |
| 15 | // with this library; see the file COPYING3. If not see | |
| 16 | // <http://www.gnu.org/licenses/>. | |
| 17 | ||
| 18 | #ifndef ULP_H | |
| 19 | #define ULP_H | |
| 20 | ||
| 21 | #include <cmath> | |
| 22 | #include <experimental/simd> | |
| 23 | #include <type_traits> | |
| 24 | #include <cfenv> | |
| 25 | ||
| 26 | namespace vir { | |
| 27 | namespace test { | |
| 28 | template <typename T, typename R = typename T::value_type> | |
| 29 | R | |
| 30 | value_type_impl(int); | |
| 31 | ||
| 32 | template <typename T> | |
| 33 | T | |
| 34 | value_type_impl(float); | |
| 35 | ||
| 36 | template <typename T> | |
| 37 | using value_type_t = decltype(value_type_impl<T>(int())); | |
| 38 | ||
| 39 | template <typename T> | |
| 40 | inline T | |
| 41 | ulp_distance(const T& val_, const T& ref_) | |
| 42 | { | |
| 43 | if constexpr (std::is_floating_point_v<value_type_t<T>>) | |
| 44 | { | |
| 45 | const int fp_exceptions = std::fetestexcept(FE_ALL_EXCEPT); | |
| 46 | T val = val_; | |
| 47 | T ref = ref_; | |
| 48 | ||
| 49 | T diff = T(); | |
| 50 | ||
| 51 | using std::abs; | |
| 52 | using std::fpclassify; | |
| 53 | using std::frexp; | |
| 54 | using std::isnan; | |
| 55 | using std::isinf; | |
| 56 | using std::ldexp; | |
| 57 | using std::max; | |
| 58 | using std::experimental::where; | |
| 59 | using TT = value_type_t<T>; | |
| 60 | ||
| 61 | where(ref == 0, val) = abs(val); | |
| 62 | where(ref == 0, diff) = 1; | |
| 63 | where(ref == 0, ref) = std::__norm_min_v<TT>; | |
| 64 | where(isinf(ref) && ref == val, ref) | |
| 65 | = 0; // where(val_ == ref_) = 0 below will fix it up | |
| 66 | ||
| 67 | where(val == 0, ref) = abs(ref); | |
| 68 | where(val == 0, diff) += 1; | |
| 69 | where(val == 0, val) = std::__norm_min_v<TT>; | |
| 70 | ||
| 71 | using I = decltype(fpclassify(std::declval<T>())); | |
| 72 | I exp = {}; | |
| 73 | frexp(ref, &exp); | |
| 74 | // lower bound for exp must be min_exponent to scale the resulting | |
| 75 | // difference from a denormal correctly | |
| 76 | exp = max(exp, I(std::__min_exponent_v<TT>)); | |
| 77 | diff += ldexp(abs(ref - val), std::__digits_v<TT> - exp); | |
| 78 | where(val_ == ref_ || (isnan(val_) && isnan(ref_)), diff) = T(); | |
| 79 | std::feclearexcept(FE_ALL_EXCEPT ^ fp_exceptions); | |
| 80 | return diff; | |
| 81 | } | |
| 82 | else | |
| 83 | { | |
| 84 | if (val_ > ref_) | |
| 85 | return val_ - ref_; | |
| 86 | else | |
| 87 | return ref_ - val_; | |
| 88 | } | |
| 89 | } | |
| 90 | ||
| 91 | template <typename T> | |
| 92 | inline T | |
| 93 | ulp_distance_signed(const T& _val, const T& _ref) | |
| 94 | { | |
| 95 | using std::copysign; | |
| 96 | return copysign(ulp_distance(_val, _ref), _val - _ref); | |
| 97 | } | |
| 98 | } // namespace test | |
| 99 | } // namespace vir | |
| 100 | ||
| 101 | #endif // ULP_H |