From 1031335f2ee1879737576fde3a3425ce0046e773 Mon Sep 17 00:00:00 2001 From: Mitch Phillips Date: Wed, 24 Jul 2024 12:58:24 +0200 Subject: [PATCH] Revert "[libc++][math] Fix undue overflowing of `std::hypot(x,y,z)` (#93350)" This reverts commit 9628777479a970db5d0c2d0b456dac6633864760. More details in https://github.com/llvm/llvm-project/pull/93350, but this broke the PowerPC sanitizer bots. --- libcxx/include/__math/hypot.h | 89 ------------------ libcxx/include/cmath | 25 ++++- .../test/libcxx/transitive_includes/cxx17.csv | 3 - .../test/libcxx/transitive_includes/cxx20.csv | 3 - .../test/libcxx/transitive_includes/cxx23.csv | 3 - .../test/libcxx/transitive_includes/cxx26.csv | 3 - .../test/std/numerics/c.math/cmath.pass.cpp | 91 ++++--------------- libcxx/test/support/fp_compare.h | 45 +++++---- 8 files changed, 65 insertions(+), 197 deletions(-) diff --git a/libcxx/include/__math/hypot.h b/libcxx/include/__math/hypot.h index 61fd260c594095..1bf193a9ab7ee9 100644 --- a/libcxx/include/__math/hypot.h +++ b/libcxx/include/__math/hypot.h @@ -15,21 +15,10 @@ #include <__type_traits/is_same.h> #include <__type_traits/promote.h> -#if _LIBCPP_STD_VER >= 17 -# include <__algorithm/max.h> -# include <__math/abs.h> -# include <__math/roots.h> -# include <__utility/pair.h> -# include -#endif - #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) # pragma GCC system_header #endif -_LIBCPP_PUSH_MACROS -#include <__undef_macros> - _LIBCPP_BEGIN_NAMESPACE_STD namespace __math { @@ -52,86 +41,8 @@ inline _LIBCPP_HIDE_FROM_ABI typename __promote<_A1, _A2>::type hypot(_A1 __x, _ return __math::hypot((__result_type)__x, (__result_type)__y); } -#if _LIBCPP_STD_VER >= 17 -// Factors needed to determine if over-/underflow might happen for `std::hypot(x,y,z)`. -// returns [overflow_threshold, overflow_scale] -template -_LIBCPP_HIDE_FROM_ABI std::pair<_Real, _Real> __hypot_factors() { - static_assert(std::numeric_limits<_Real>::is_iec559); - - if constexpr (std::is_same_v<_Real, float>) { - static_assert(-125 == std::numeric_limits<_Real>::min_exponent); - static_assert(+128 == std::numeric_limits<_Real>::max_exponent); - return {0x1.0p+62f, 0x1.0p-70f}; - } else if constexpr (std::is_same_v<_Real, double>) { - static_assert(-1021 == std::numeric_limits<_Real>::min_exponent); - static_assert(+1024 == std::numeric_limits<_Real>::max_exponent); - return {0x1.0p+510, 0x1.0p-600}; - } else { // long double - static_assert(std::is_same_v<_Real, long double>); - - // preprocessor guard necessary, otherwise literals (e.g. `0x1.0p+8'190l`) throw warnings even when shielded by `if - // constexpr` -# if __DBL_MAX_EXP__ == __LDBL_MAX_EXP__ - static_assert(sizeof(_Real) == sizeof(double)); - return static_cast>(__math::__hypot_factors()); -# else - static_assert(sizeof(_Real) > sizeof(double)); - static_assert(-16381 == std::numeric_limits<_Real>::min_exponent); - static_assert(+16384 == std::numeric_limits<_Real>::max_exponent); - return {0x1.0p+8190l, 0x1.0p-9000l}; -# endif - } -} - -// Computes the three-dimensional hypotenuse: `std::hypot(x,y,z)`. -// The naive implementation might over-/underflow which is why this implementation is more involved: -// If the square of an argument might run into issues, we scale the arguments appropriately. -// See https://github.com/llvm/llvm-project/issues/92782 for a detailed discussion and summary. -template -_LIBCPP_HIDE_FROM_ABI _Real __hypot(_Real __x, _Real __y, _Real __z) { - const _Real __max_abs = std::max(__math::fabs(__x), std::max(__math::fabs(__y), __math::fabs(__z))); - const auto [__overflow_threshold, __overflow_scale] = __math::__hypot_factors<_Real>(); - _Real __scale; - if (__max_abs > __overflow_threshold) { // x*x + y*y + z*z might overflow - __scale = __overflow_scale; - __x *= __scale; - __y *= __scale; - __z *= __scale; - } else if (__max_abs < 1 / __overflow_threshold) { // x*x + y*y + z*z might underflow - __scale = 1 / __overflow_scale; - __x *= __scale; - __y *= __scale; - __z *= __scale; - } else - __scale = 1; - return __math::sqrt(__x * __x + __y * __y + __z * __z) / __scale; -} - -inline _LIBCPP_HIDE_FROM_ABI float hypot(float __x, float __y, float __z) { return __math::__hypot(__x, __y, __z); } - -inline _LIBCPP_HIDE_FROM_ABI double hypot(double __x, double __y, double __z) { return __math::__hypot(__x, __y, __z); } - -inline _LIBCPP_HIDE_FROM_ABI long double hypot(long double __x, long double __y, long double __z) { - return __math::__hypot(__x, __y, __z); -} - -template && is_arithmetic_v<_A2> && is_arithmetic_v<_A3>, int> = 0 > -_LIBCPP_HIDE_FROM_ABI typename __promote<_A1, _A2, _A3>::type hypot(_A1 __x, _A2 __y, _A3 __z) _NOEXCEPT { - using __result_type = typename __promote<_A1, _A2, _A3>::type; - static_assert(!( - std::is_same_v<_A1, __result_type> && std::is_same_v<_A2, __result_type> && std::is_same_v<_A3, __result_type>)); - return __math::__hypot( - static_cast<__result_type>(__x), static_cast<__result_type>(__y), static_cast<__result_type>(__z)); -} -#endif - } // namespace __math _LIBCPP_END_NAMESPACE_STD -_LIBCPP_POP_MACROS #endif // _LIBCPP___MATH_HYPOT_H diff --git a/libcxx/include/cmath b/libcxx/include/cmath index 6480c4678ce33d..3c22604a683c33 100644 --- a/libcxx/include/cmath +++ b/libcxx/include/cmath @@ -313,7 +313,6 @@ constexpr long double lerp(long double a, long double b, long double t) noexcept */ #include <__config> -#include <__math/hypot.h> #include <__type_traits/enable_if.h> #include <__type_traits/is_arithmetic.h> #include <__type_traits/is_constant_evaluated.h> @@ -554,6 +553,30 @@ using ::scalbnl _LIBCPP_USING_IF_EXISTS; using ::tgammal _LIBCPP_USING_IF_EXISTS; using ::truncl _LIBCPP_USING_IF_EXISTS; +#if _LIBCPP_STD_VER >= 17 +inline _LIBCPP_HIDE_FROM_ABI float hypot(float __x, float __y, float __z) { + return sqrt(__x * __x + __y * __y + __z * __z); +} +inline _LIBCPP_HIDE_FROM_ABI double hypot(double __x, double __y, double __z) { + return sqrt(__x * __x + __y * __y + __z * __z); +} +inline _LIBCPP_HIDE_FROM_ABI long double hypot(long double __x, long double __y, long double __z) { + return sqrt(__x * __x + __y * __y + __z * __z); +} + +template +inline _LIBCPP_HIDE_FROM_ABI +typename enable_if_t< is_arithmetic<_A1>::value && is_arithmetic<_A2>::value && is_arithmetic<_A3>::value, + __promote<_A1, _A2, _A3> >::type +hypot(_A1 __lcpp_x, _A2 __lcpp_y, _A3 __lcpp_z) _NOEXCEPT { + typedef typename __promote<_A1, _A2, _A3>::type __result_type; + static_assert( + !(is_same<_A1, __result_type>::value && is_same<_A2, __result_type>::value && is_same<_A3, __result_type>::value), + ""); + return std::hypot((__result_type)__lcpp_x, (__result_type)__lcpp_y, (__result_type)__lcpp_z); +} +#endif + template ::value, int> = 0> _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool __constexpr_isnan(_A1 __lcpp_x) _NOEXCEPT { #if __has_builtin(__builtin_isnan) diff --git a/libcxx/test/libcxx/transitive_includes/cxx17.csv b/libcxx/test/libcxx/transitive_includes/cxx17.csv index 8099d2b79c4bee..2c028462144eee 100644 --- a/libcxx/test/libcxx/transitive_includes/cxx17.csv +++ b/libcxx/test/libcxx/transitive_includes/cxx17.csv @@ -130,9 +130,6 @@ chrono type_traits chrono vector chrono version cinttypes cstdint -cmath cstddef -cmath cstdint -cmath initializer_list cmath limits cmath type_traits cmath version diff --git a/libcxx/test/libcxx/transitive_includes/cxx20.csv b/libcxx/test/libcxx/transitive_includes/cxx20.csv index 384e51b101f311..982c2013e34170 100644 --- a/libcxx/test/libcxx/transitive_includes/cxx20.csv +++ b/libcxx/test/libcxx/transitive_includes/cxx20.csv @@ -135,9 +135,6 @@ chrono type_traits chrono vector chrono version cinttypes cstdint -cmath cstddef -cmath cstdint -cmath initializer_list cmath limits cmath type_traits cmath version diff --git a/libcxx/test/libcxx/transitive_includes/cxx23.csv b/libcxx/test/libcxx/transitive_includes/cxx23.csv index 46b833d143f39a..8ffb71d8b566b0 100644 --- a/libcxx/test/libcxx/transitive_includes/cxx23.csv +++ b/libcxx/test/libcxx/transitive_includes/cxx23.csv @@ -83,9 +83,6 @@ chrono string_view chrono vector chrono version cinttypes cstdint -cmath cstddef -cmath cstdint -cmath initializer_list cmath limits cmath version codecvt cctype diff --git a/libcxx/test/libcxx/transitive_includes/cxx26.csv b/libcxx/test/libcxx/transitive_includes/cxx26.csv index 46b833d143f39a..8ffb71d8b566b0 100644 --- a/libcxx/test/libcxx/transitive_includes/cxx26.csv +++ b/libcxx/test/libcxx/transitive_includes/cxx26.csv @@ -83,9 +83,6 @@ chrono string_view chrono vector chrono version cinttypes cstdint -cmath cstddef -cmath cstdint -cmath initializer_list cmath limits cmath version codecvt cctype diff --git a/libcxx/test/std/numerics/c.math/cmath.pass.cpp b/libcxx/test/std/numerics/c.math/cmath.pass.cpp index 6028aa5a211034..f53d8f259f47e2 100644 --- a/libcxx/test/std/numerics/c.math/cmath.pass.cpp +++ b/libcxx/test/std/numerics/c.math/cmath.pass.cpp @@ -12,17 +12,14 @@ // -#include #include #include #include #include -#include "fp_compare.h" #include "test_macros.h" #include "hexfloat.h" #include "truncate_fp.h" -#include "type_algorithms.h" // convertible to int/float/double/etc template @@ -1116,56 +1113,6 @@ void test_fmin() assert(std::fmin(1,0) == 0); } -#if TEST_STD_VER >= 17 -struct TestHypot3 { - template - void operator()() const { - const auto check = [](Real elem, Real abs_tol) { - assert(std::isfinite(std::hypot(elem, Real(0), Real(0)))); - assert(fptest_close(std::hypot(elem, Real(0), Real(0)), elem, abs_tol)); - assert(std::isfinite(std::hypot(elem, elem, Real(0)))); - assert(fptest_close(std::hypot(elem, elem, Real(0)), std::sqrt(Real(2)) * elem, abs_tol)); - assert(std::isfinite(std::hypot(elem, elem, elem))); - assert(fptest_close(std::hypot(elem, elem, elem), std::sqrt(Real(3)) * elem, abs_tol)); - }; - - { // check for overflow - const auto [elem, abs_tol] = []() -> std::array { - if constexpr (std::is_same_v) - return {1e20f, 1e16f}; - else if constexpr (std::is_same_v) - return {1e300, 1e287}; - else { // long double -# if __DBL_MAX_EXP__ == __LDBL_MAX_EXP__ - return {1e300l, 1e287l}; // 64-bit -# else - return {1e4000l, 1e3985l}; // 80- or 128-bit -# endif - } - }(); - check(elem, abs_tol); - } - - { // check for underflow - const auto [elem, abs_tol] = []() -> std::array { - if constexpr (std::is_same_v) - return {1e-20f, 1e-24f}; - else if constexpr (std::is_same_v) - return {1e-287, 1e-300}; - else { // long double -# if __DBL_MAX_EXP__ == __LDBL_MAX_EXP__ - return {1e-287l, 1e-300l}; // 64-bit -# else - return {1e-3985l, 1e-4000l}; // 80- or 128-bit -# endif - } - }(); - check(elem, abs_tol); - } - } -}; -#endif - void test_hypot() { static_assert((std::is_same::value), ""); @@ -1188,31 +1135,25 @@ void test_hypot() static_assert((std::is_same::value), ""); assert(std::hypot(3,4) == 5); -#if TEST_STD_VER >= 17 - // clang-format off - static_assert((std::is_same_v)); - static_assert((std::is_same_v)); - static_assert((std::is_same_v)); - static_assert((std::is_same_v)); - static_assert((std::is_same_v)); - static_assert((std::is_same_v)); - static_assert((std::is_same_v)); - static_assert((std::is_same_v)); - static_assert((std::is_same_v)); - static_assert((std::is_same_v)); - static_assert((std::is_same_v)); - static_assert((std::is_same_v)); - static_assert((std::is_same_v)); - static_assert((std::is_same_v)); - static_assert((std::is_same_v)); - // clang-format on +#if TEST_STD_VER > 14 + static_assert((std::is_same::value), ""); + static_assert((std::is_same::value), ""); + static_assert((std::is_same::value), ""); + static_assert((std::is_same::value), ""); + static_assert((std::is_same::value), ""); + static_assert((std::is_same::value), ""); + static_assert((std::is_same::value), ""); + static_assert((std::is_same::value), ""); + static_assert((std::is_same::value), ""); + static_assert((std::is_same::value), ""); + static_assert((std::is_same::value), ""); + static_assert((std::is_same::value), ""); + static_assert((std::is_same::value), ""); + static_assert((std::is_same::value), ""); + static_assert((std::is_same::value), ""); assert(std::hypot(2,3,6) == 7); assert(std::hypot(1,4,8) == 9); - - // Check for undue over-/underflows of intermediate results. - // See discussion at https://github.com/llvm/llvm-project/issues/92782. - types::for_each(types::floating_point_types(), TestHypot3()); #endif } diff --git a/libcxx/test/support/fp_compare.h b/libcxx/test/support/fp_compare.h index 3088a211dadc3b..1d1933b0bcd813 100644 --- a/libcxx/test/support/fp_compare.h +++ b/libcxx/test/support/fp_compare.h @@ -9,34 +9,39 @@ #ifndef SUPPORT_FP_COMPARE_H #define SUPPORT_FP_COMPARE_H -#include // for std::abs -#include // for std::max +#include // for std::abs +#include // for std::max #include -#include <__config> // See https://www.boost.org/doc/libs/1_70_0/libs/test/doc/html/boost_test/testing_tools/extended_comparison/floating_point/floating_points_comparison_theory.html -template -bool fptest_close(T val, T expected, T eps) { - _LIBCPP_CONSTEXPR T zero = T(0); - assert(eps >= zero); +template +bool fptest_close(T val, T expected, T eps) +{ + constexpr T zero = T(0); + assert(eps >= zero); - // Handle the zero cases - if (eps == zero) - return val == expected; - if (val == zero) - return std::abs(expected) <= eps; - if (expected == zero) - return std::abs(val) <= eps; + // Handle the zero cases + if (eps == zero) return val == expected; + if (val == zero) return std::abs(expected) <= eps; + if (expected == zero) return std::abs(val) <= eps; - return std::abs(val - expected) < eps && std::abs(val - expected) / std::abs(val) < eps; + return std::abs(val - expected) < eps + && std::abs(val - expected)/std::abs(val) < eps; } -template -bool fptest_close_pct(T val, T expected, T percent) { - assert(percent >= T(0)); - T eps = (percent / T(100)) * std::max(std::abs(val), std::abs(expected)); - return fptest_close(val, expected, eps); +template +bool fptest_close_pct(T val, T expected, T percent) +{ + constexpr T zero = T(0); + assert(percent >= zero); + + // Handle the zero cases + if (percent == zero) return val == expected; + T eps = (percent / T(100)) * std::max(std::abs(val), std::abs(expected)); + + return fptest_close(val, expected, eps); } + #endif // SUPPORT_FP_COMPARE_H