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[CUDA] added cmath wrappers to unbreak CUDA compilation after D79555
libc++ introduced a handful of internal functions that may or may not be constexpr, depending on C++ version. For pre-constexpr variants we must declare __device__ counterparts. Otherwise the code fails to compile on the GPU side. See https://reviews.llvm.org/D79555 Differential Revision: https://reviews.llvm.org/D141555
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/*===---- cmath - CUDA wrapper for <cmath> ---------------------------------=== | ||
* | ||
* Permission is hereby granted, free of charge, to any person obtaining a copy | ||
* of this software and associated documentation files (the "Software"), to deal | ||
* in the Software without restriction, including without limitation the rights | ||
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | ||
* copies of the Software, and to permit persons to whom the Software is | ||
* furnished to do so, subject to the following conditions: | ||
* | ||
* The above copyright notice and this permission notice shall be included in | ||
* all copies or substantial portions of the Software. | ||
* | ||
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | ||
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | ||
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | ||
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | ||
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | ||
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN | ||
* THE SOFTWARE. | ||
* | ||
*===-----------------------------------------------------------------------=== | ||
*/ | ||
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#ifndef __CLANG_CUDA_WRAPPERS_CMATH | ||
#define __CLANG_CUDA_WRAPPERS_CMATH | ||
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#include_next <cmath> | ||
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#if defined(_LIBCPP_STD_VER) | ||
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// libc++ will need long double variants of these functions, but CUDA does not | ||
// provide them. We'll provide their declarations, which should allow the | ||
// headers to parse, but would not allow accidental use of them on a GPU. | ||
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__attribute__((device)) long double logb(long double); | ||
__attribute__((device)) long double scalbn(long double, int); | ||
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namespace std { | ||
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// For __constexpr_fmin/fmax we only need device-side overloads before c++14 | ||
// where they are not constexpr. | ||
#if _LIBCPP_STD_VER < 14 | ||
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__attribute__((device)) | ||
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 float __constexpr_fmax(float __x, float __y) _NOEXCEPT { | ||
return __builtin_fmaxf(__x, __y); | ||
} | ||
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__attribute__((device)) | ||
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 double __constexpr_fmax(double __x, double __y) _NOEXCEPT { | ||
return __builtin_fmax(__x, __y); | ||
} | ||
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__attribute__((device)) | ||
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 long double | ||
__constexpr_fmax(long double __x, long double __y) _NOEXCEPT { | ||
return __builtin_fmaxl(__x, __y); | ||
} | ||
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template <class _Tp, class _Up, __enable_if_t<is_arithmetic<_Tp>::value && is_arithmetic<_Up>::value, int> = 0> | ||
__attribute__((device)) | ||
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 typename __promote<_Tp, _Up>::type | ||
__constexpr_fmax(_Tp __x, _Up __y) _NOEXCEPT { | ||
using __result_type = typename __promote<_Tp, _Up>::type; | ||
return std::__constexpr_fmax(static_cast<__result_type>(__x), static_cast<__result_type>(__y)); | ||
} | ||
#endif // _LIBCPP_STD_VER < 14 | ||
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// For logb/scalbn templates we must always provide device overloads because | ||
// libc++ implementation uses __builtin_XXX which gets translated into a libcall | ||
// which we can't handle on GPU. We need to forward those to CUDA-provided | ||
// implementations. | ||
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template <class _Tp> | ||
__attribute__((device)) | ||
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp __constexpr_logb(_Tp __x) { | ||
return ::logb(__x); | ||
} | ||
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template <class _Tp> | ||
__attribute__((device)) | ||
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp __constexpr_scalbn(_Tp __x, int __exp) { | ||
return ::scalbn(__x, __exp); | ||
} | ||
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} // namespace std// | ||
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#endif // _LIBCPP_STD_VER | ||
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#endif // include guard |