libcxx/include/experimental/__simd/utility.h

   1 // -*- C++ -*-
   2 //===----------------------------------------------------------------------===//
   3 //
   4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   5 // See https://llvm.org/LICENSE.txt for license information.
   6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #ifndef _LIBCPP_EXPERIMENTAL___SIMD_UTILITY_H
  11 #define _LIBCPP_EXPERIMENTAL___SIMD_UTILITY_H
  12
  13 #include <__type_traits/is_arithmetic.h>
  14 #include <__type_traits/is_const.h>
  15 #include <__type_traits/is_constant_evaluated.h>
  16 #include <__type_traits/is_convertible.h>
  17 #include <__type_traits/is_same.h>
  18 #include <__type_traits/is_unsigned.h>
  19 #include <__type_traits/is_volatile.h>
  20 #include <__type_traits/void_t.h>
  21 #include <__utility/declval.h>
  22 #include <__utility/integer_sequence.h>
  23 #include <cstdint>
  24 #include <limits>
  25
  26 _LIBCPP_PUSH_MACROS
  27 #include <__undef_macros>
  28
  29 #if _LIBCPP_STD_VER >= 17 && defined(_LIBCPP_ENABLE_EXPERIMENTAL)
  30
  31 _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL
  32 inline namespace parallelism_v2 {
  33 template <class _Tp>
  34 inline constexpr bool __is_vectorizable_v =
  35     is_arithmetic_v<_Tp> && !is_const_v<_Tp> && !is_volatile_v<_Tp> && !is_same_v<_Tp, bool>;
  36
  37 template <class _Tp>
  38 _LIBCPP_HIDE_FROM_ABI auto __choose_mask_type() {
  39   if constexpr (sizeof(_Tp) == 1) {
  40     return uint8_t{};
  41   } else if constexpr (sizeof(_Tp) == 2) {
  42     return uint16_t{};
  43   } else if constexpr (sizeof(_Tp) == 4) {
  44     return uint32_t{};
  45   } else if constexpr (sizeof(_Tp) == 8) {
  46     return uint64_t{};
  47   }
  48 #  ifndef _LIBCPP_HAS_NO_INT128
  49   else if constexpr (sizeof(_Tp) == 16) {
  50     return __uint128_t{};
  51   }
  52 #  endif
  53   else
  54     static_assert(sizeof(_Tp) == 0, "Unexpected size");
  55 }
  56
  57 template <class _Tp>
  58 _LIBCPP_HIDE_FROM_ABI auto constexpr __set_all_bits(bool __v) {
  59   return __v ? (numeric_limits<decltype(__choose_mask_type<_Tp>())>::max()) : 0;
  60 }
  61
  62 template <class _From, class _To, class = void>
  63 inline constexpr bool __is_non_narrowing_convertible_v = false;
  64
  65 template <class _From, class _To>
  66 inline constexpr bool __is_non_narrowing_convertible_v<_From, _To, std::void_t<decltype(_To{std::declval<_From>()})>> =
  67     true;
  68
  69 template <class _Tp, class _Up>
  70 inline constexpr bool __can_broadcast_v =
  71     (__is_vectorizable_v<_Up> && __is_non_narrowing_convertible_v<_Up, _Tp>) ||
  72     (!__is_vectorizable_v<_Up> && is_convertible_v<_Up, _Tp>) || is_same_v<_Up, int> ||
  73     (is_same_v<_Up, unsigned int> && is_unsigned_v<_Tp>);
  74
  75 template <class _Tp, class _Generator, std::size_t _Idx, class = void>
  76 inline constexpr bool __is_well_formed = false;
  77
  78 template <class _Tp, class _Generator, std::size_t _Idx>
  79 inline constexpr bool
  80     __is_well_formed<_Tp,
  81                      _Generator,
  82                      _Idx,
  83                      std::void_t<decltype(std::declval<_Generator>()(integral_constant<size_t, _Idx>()))>> =
  84         __can_broadcast_v<_Tp, decltype(std::declval<_Generator>()(integral_constant<size_t, _Idx>()))>;
  85
  86 template <class _Tp, class _Generator, std::size_t... _Idxes>
  87 _LIBCPP_HIDE_FROM_ABI constexpr bool __can_generate(index_sequence<_Idxes...>) {
  88   return (true && ... && __is_well_formed<_Tp, _Generator, _Idxes>);
  89 }
  90
  91 template <class _Tp, class _Generator, std::size_t _Size>
  92 inline constexpr bool __can_generate_v = experimental::__can_generate<_Tp, _Generator>(make_index_sequence<_Size>());
  93
  94 } // namespace parallelism_v2
  95 _LIBCPP_END_NAMESPACE_EXPERIMENTAL
  96
  97 #endif // _LIBCPP_STD_VER >= 17 && defined(_LIBCPP_ENABLE_EXPERIMENTAL)
  98
  99 _LIBCPP_POP_MACROS
 100
 101 #endif // _LIBCPP_EXPERIMENTAL___SIMD_UTILITY_H