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 <__config>
  14 #include <__cstddef/size_t.h>
  15 #include <__type_traits/is_arithmetic.h>
  16 #include <__type_traits/is_const.h>
  17 #include <__type_traits/is_constant_evaluated.h>
  18 #include <__type_traits/is_convertible.h>
  19 #include <__type_traits/is_same.h>
  20 #include <__type_traits/is_unsigned.h>
  21 #include <__type_traits/is_volatile.h>
  22 #include <__type_traits/void_t.h>
  23 #include <__utility/declval.h>
  24 #include <__utility/integer_sequence.h>
  25 #include <cstdint>
  26 #include <limits>
  27
  28 _LIBCPP_PUSH_MACROS
  29 #include <__undef_macros>
  30
  31 #if _LIBCPP_STD_VER >= 17 && defined(_LIBCPP_ENABLE_EXPERIMENTAL)
  32
  33 _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL
  34 inline namespace parallelism_v2 {
  35 template <class _Tp>
  36 inline constexpr bool __is_vectorizable_v =
  37     is_arithmetic_v<_Tp> && !is_const_v<_Tp> && !is_volatile_v<_Tp> && !is_same_v<_Tp, bool>;
  38
  39 template <class _Tp>
  40 _LIBCPP_HIDE_FROM_ABI auto __choose_mask_type() {
  41   if constexpr (sizeof(_Tp) == 1) {
  42     return uint8_t{};
  43   } else if constexpr (sizeof(_Tp) == 2) {
  44     return uint16_t{};
  45   } else if constexpr (sizeof(_Tp) == 4) {
  46     return uint32_t{};
  47   } else if constexpr (sizeof(_Tp) == 8) {
  48     return uint64_t{};
  49   }
  50 #  if _LIBCPP_HAS_INT128
  51   else if constexpr (sizeof(_Tp) == 16) {
  52     return __uint128_t{};
  53   }
  54 #  endif
  55   else
  56     static_assert(sizeof(_Tp) == 0, "Unexpected size");
  57 }
  58
  59 template <class _Tp>
  60 _LIBCPP_HIDE_FROM_ABI auto constexpr __set_all_bits(bool __v) {
  61   return __v ? (numeric_limits<decltype(__choose_mask_type<_Tp>())>::max()) : 0;
  62 }
  63
  64 template <class _From, class _To, class = void>
  65 inline constexpr bool __is_non_narrowing_convertible_v = false;
  66
  67 template <class _From, class _To>
  68 inline constexpr bool __is_non_narrowing_convertible_v<_From, _To, std::void_t<decltype(_To{std::declval<_From>()})>> =
  69     true;
  70
  71 template <class _Tp, class _Up>
  72 inline constexpr bool __can_broadcast_v =
  73     (__is_vectorizable_v<_Up> && __is_non_narrowing_convertible_v<_Up, _Tp>) ||
  74     (!__is_vectorizable_v<_Up> && is_convertible_v<_Up, _Tp>) || is_same_v<_Up, int> ||
  75     (is_same_v<_Up, unsigned int> && is_unsigned_v<_Tp>);
  76
  77 template <class _Tp, class _Generator, std::size_t _Idx, class = void>
  78 inline constexpr bool __is_well_formed = false;
  79
  80 template <class _Tp, class _Generator, std::size_t _Idx>
  81 inline constexpr bool
  82     __is_well_formed<_Tp,
  83                      _Generator,
  84                      _Idx,
  85                      std::void_t<decltype(std::declval<_Generator>()(integral_constant<size_t, _Idx>()))>> =
  86         __can_broadcast_v<_Tp, decltype(std::declval<_Generator>()(integral_constant<size_t, _Idx>()))>;
  87
  88 template <class _Tp, class _Generator, std::size_t... _Idxes>
  89 _LIBCPP_HIDE_FROM_ABI constexpr bool __can_generate(index_sequence<_Idxes...>) {
  90   return (true && ... && __is_well_formed<_Tp, _Generator, _Idxes>);
  91 }
  92
  93 template <class _Tp, class _Generator, std::size_t _Size>
  94 inline constexpr bool __can_generate_v = experimental::__can_generate<_Tp, _Generator>(make_index_sequence<_Size>());
  95
  96 } // namespace parallelism_v2
  97 _LIBCPP_END_NAMESPACE_EXPERIMENTAL
  98
  99 #endif // _LIBCPP_STD_VER >= 17 && defined(_LIBCPP_ENABLE_EXPERIMENTAL)
 100
 101 _LIBCPP_POP_MACROS
 102
 103 #endif // _LIBCPP_EXPERIMENTAL___SIMD_UTILITY_H