From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2181) id 60B653858D33; Tue, 6 Jun 2023 15:59:15 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 60B653858D33 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1686067155; bh=df6BW4PuRma5EDo7f7s5CzkBlPZeOQaZx6Qxvj4WD4Y=; h=From:To:Subject:Date:From; b=C0ee4wzC4h6vLBhM3jEUeDN5CxpzfUpQGndHGc4WpbJInImqxUxUoo8+poOtibwnT +tbj10we4aS7dTVi52r+uUbJCvNLOhbKRJNhIcfiCbwwwamivIWMiTvhZdE8zxz1Id sK+lYHDnbGbh+8o6nr+/Dpt3c/cLk9q750vr/rW4= MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: Jonathan Wakely To: gcc-cvs@gcc.gnu.org, libstdc++-cvs@gcc.gnu.org Subject: [gcc r14-1582] libstdc++: Make std::numeric_limits<__float128> more portable [PR104772] X-Act-Checkin: gcc X-Git-Author: Jonathan Wakely X-Git-Refname: refs/heads/master X-Git-Oldrev: 97a5e8a2a48d162744a5bd60a012ce6fca13cbbe X-Git-Newrev: 6261d10521f9fdc2a43d54b4dc365025288aa8e9 Message-Id: <20230606155915.60B653858D33@sourceware.org> Date: Tue, 6 Jun 2023 15:59:15 +0000 (GMT) List-Id: https://gcc.gnu.org/g:6261d10521f9fdc2a43d54b4dc365025288aa8e9 commit r14-1582-g6261d10521f9fdc2a43d54b4dc365025288aa8e9 Author: Jonathan Wakely Date: Mon Jun 5 16:14:29 2023 +0100 libstdc++: Make std::numeric_limits<__float128> more portable [PR104772] This redefines std::numeric_limits<__float128> so that it works with non-GCC compilers. The previous definition didn't work with Clang, due to it not supporting __builtin_high_valq, __builtin_nanq, and __builtin_nansq. It also didn't work in strict modes, due to using Q literal suffixes. The new definition uses the Q suffixes when supported, or calculates the correct values using __float128 arithmetic from double values. Ideally the values would be defined as hexadecimal-floating-point-literals, but that won't work for C++14 and older. The only member that can't be defined this way is signaling_NaN() which still requires a built-in. If __builtin_nansq is not supported, try to use __builtin_nansf128 (with a possibly-redundant bit_cast) and if that isn't supported, return a quiet NaN and define has_signaling_NaN and is_iec754 to be false. libstdc++-v3/ChangeLog: PR libstdc++/104772 * include/std/limits: (numeric_limits<__float128>): Define for __STRICT_ANSI__ as well. * testsuite/18_support/numeric_limits/128bit.cc: Remove check for __STRICT_ANSI__. Co-authored-by: Jakub Jelinek Diff: --- libstdc++-v3/include/std/limits | 95 ++++++++++++++++++---- .../testsuite/18_support/numeric_limits/128bit.cc | 2 +- 2 files changed, 80 insertions(+), 17 deletions(-) diff --git a/libstdc++-v3/include/std/limits b/libstdc++-v3/include/std/limits index 5f341e63b93..52b19ef8264 100644 --- a/libstdc++-v3/include/std/limits +++ b/libstdc++-v3/include/std/limits @@ -2071,9 +2071,11 @@ __glibcxx_float_n(128) }; #endif -#endif +#endif // C++23 -#if defined(_GLIBCXX_USE_FLOAT128) && !defined(__STRICT_ANSI__) +#if defined(_GLIBCXX_USE_FLOAT128) +// We either need Q literal suffixes, or IEEE double. +#if ! defined(__STRICT_ANSI__) || defined(_GLIBCXX_DOUBLE_IS_IEEE_BINARY64) __extension__ template<> struct numeric_limits<__float128> @@ -2082,11 +2084,28 @@ __glibcxx_float_n(128) static _GLIBCXX_CONSTEXPR __float128 min() _GLIBCXX_USE_NOEXCEPT - { return __extension__ 3.36210314311209350626267781732175260e-4932Q; } + { +#ifdef __STRICT_ANSI__ + // 0x1.0p-30 * 0x1.0p-16352 + return double(9.3132257461547852e-10) * _S_1pm16352(); +#else + return __extension__ 0x1.0p-16382Q; +#endif + } static _GLIBCXX_CONSTEXPR __float128 max() _GLIBCXX_USE_NOEXCEPT - { return __extension__ 1.18973149535723176508575932662800702e+4932Q; } + { +#ifdef __STRICT_ANSI__ + // (0x1.fffffffffffffp+127 + 0x0.fffffffffffffp+75 + 0x0.ffp+23) + // * 0x1.0p16256 + return (__float128(double(3.4028236692093843e+38)) + + double(3.7778931862957153e+22) + double(8.35584e+6)) + * _S_1p16256(); +#else + return __extension__ 0x1.ffffffffffffffffffffffffffffp+16383Q; +#endif + } static _GLIBCXX_CONSTEXPR __float128 lowest() _GLIBCXX_USE_NOEXCEPT @@ -2094,8 +2113,9 @@ __glibcxx_float_n(128) static _GLIBCXX_USE_CONSTEXPR int digits = 113; static _GLIBCXX_USE_CONSTEXPR int digits10 = 33; - static _GLIBCXX_USE_CONSTEXPR int max_digits10 - = __glibcxx_max_digits10 (112); +#if __cplusplus >= 201103L + static constexpr int max_digits10 = 35; +#endif static _GLIBCXX_USE_CONSTEXPR bool is_signed = true; static _GLIBCXX_USE_CONSTEXPR bool is_integer = false; static _GLIBCXX_USE_CONSTEXPR bool is_exact = false; @@ -2103,10 +2123,10 @@ __glibcxx_float_n(128) static _GLIBCXX_CONSTEXPR __float128 epsilon() _GLIBCXX_USE_NOEXCEPT - { return __extension__ 1.92592994438723585305597794258492732e-34Q; } + { return double(1.9259299443872359e-34); } static _GLIBCXX_CONSTEXPR __float128 - round_error() _GLIBCXX_USE_NOEXCEPT { return __extension__ 0.5Q; } + round_error() _GLIBCXX_USE_NOEXCEPT { return 0.5; } static _GLIBCXX_USE_CONSTEXPR int min_exponent = -16381; static _GLIBCXX_USE_CONSTEXPR int min_exponent10 = -4931; @@ -2115,29 +2135,48 @@ __glibcxx_float_n(128) static _GLIBCXX_USE_CONSTEXPR bool has_infinity = 1; static _GLIBCXX_USE_CONSTEXPR bool has_quiet_NaN = 1; - static _GLIBCXX_USE_CONSTEXPR bool has_signaling_NaN = has_quiet_NaN; +#if __has_builtin(__builtin_nansq) \ + || (__has_builtin(__builtin_bit_cast) && __has_builtin(__builtin_nansf128)) + static _GLIBCXX_USE_CONSTEXPR bool has_signaling_NaN = true; +#else + static _GLIBCXX_USE_CONSTEXPR bool has_signaling_NaN = false; +#endif static _GLIBCXX_USE_CONSTEXPR float_denorm_style has_denorm = denorm_present; static _GLIBCXX_USE_CONSTEXPR bool has_denorm_loss = false; static _GLIBCXX_CONSTEXPR __float128 infinity() _GLIBCXX_USE_NOEXCEPT - { return __builtin_huge_valq(); } + { return __builtin_huge_val(); } static _GLIBCXX_CONSTEXPR __float128 quiet_NaN() _GLIBCXX_USE_NOEXCEPT - { return __builtin_nanq(""); } + { return __builtin_nan(""); } static _GLIBCXX_CONSTEXPR __float128 signaling_NaN() _GLIBCXX_USE_NOEXCEPT - { return __builtin_nansq(""); } + { +#if __has_builtin(__builtin_nansq) + return __builtin_nansq(""); +#elif __has_builtin(__builtin_bit_cast) && __has_builtin(__builtin_nansf128) + return __builtin_bit_cast(__float128, __builtin_nansf128("")); +#else + return quiet_NaN(); +#endif + } static _GLIBCXX_CONSTEXPR __float128 denorm_min() _GLIBCXX_USE_NOEXCEPT - { return __extension__ 6.47517511943802511092443895822764655e-4966Q; } + { +#if defined(__STRICT_ANSI__) || defined(__INTEL_COMPILER) + // 0x1.0p-142 * 0x1.0p-16352 + return double(1.7936620343357659e-43) * _S_1pm16352(); +#else + return __extension__ 0x1.0p-16494Q; +#endif + } - static _GLIBCXX_USE_CONSTEXPR bool is_iec559 - = has_infinity && has_quiet_NaN && has_denorm == denorm_present; + static _GLIBCXX_USE_CONSTEXPR bool is_iec559 = has_signaling_NaN; static _GLIBCXX_USE_CONSTEXPR bool is_bounded = true; static _GLIBCXX_USE_CONSTEXPR bool is_modulo = false; @@ -2145,8 +2184,32 @@ __glibcxx_float_n(128) static _GLIBCXX_USE_CONSTEXPR bool tinyness_before = false; static _GLIBCXX_USE_CONSTEXPR float_round_style round_style = round_to_nearest; + +#if defined(__STRICT_ANSI__) || defined(__INTEL_COMPILER) + private: + static _GLIBCXX_CONSTEXPR __float128 + _S_4p(__float128 __v) _GLIBCXX_USE_NOEXCEPT + { return __v * __v * __v * __v; } + + static _GLIBCXX_CONSTEXPR __float128 + _S_1pm4088() _GLIBCXX_USE_NOEXCEPT + { return _S_4p(/* 0x1.0p-1022 */ double(2.2250738585072014e-308)); } + + static _GLIBCXX_CONSTEXPR __float128 + _S_1pm16352() _GLIBCXX_USE_NOEXCEPT + { return _S_4p(_S_1pm4088()); } + + static _GLIBCXX_CONSTEXPR __float128 + _S_1p4064() _GLIBCXX_USE_NOEXCEPT + { return _S_4p(/* 0x1.0p+1016 */ double(7.0222388080559215e+305)); } + + static _GLIBCXX_CONSTEXPR __float128 + _S_1p16256() _GLIBCXX_USE_NOEXCEPT + { return _S_4p(_S_1p4064()); } +#endif }; -#endif // _GLIBCXX_USE_FLOAT128 && ! __STRICT_ANSI__ +#endif // !__STRICT_ANSI__ || DOUBLE_IS_IEEE_BINARY64 +#endif // _GLIBCXX_USE_FLOAT128 _GLIBCXX_END_NAMESPACE_VERSION } // namespace diff --git a/libstdc++-v3/testsuite/18_support/numeric_limits/128bit.cc b/libstdc++-v3/testsuite/18_support/numeric_limits/128bit.cc index e8ea568df94..b13d83776ba 100644 --- a/libstdc++-v3/testsuite/18_support/numeric_limits/128bit.cc +++ b/libstdc++-v3/testsuite/18_support/numeric_limits/128bit.cc @@ -2,7 +2,7 @@ #include -#if __SIZEOF_FLOAT128__ && !defined __STRICT_ANSI__ +#if __SIZEOF_FLOAT128__ __extension__ template class std::numeric_limits<__float128>; #endif