libstdc++-v3/include/bits/simd_reductions.h

// Implementation of <simd> -*- C++ -*-

// Copyright The GNU Toolchain Authors.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

#ifndef _GLIBCXX_SIMD_REDUCTIONS_H
#define _GLIBCXX_SIMD_REDUCTIONS_H 1

#ifdef _GLIBCXX_SYSHDR
#pragma GCC system_header
#endif

#if __cplusplus >= 202400L

#include "simd_vec.h"

// psabi warnings are bogus because the ABI of the internal types never leaks into user code
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wpsabi"

// [simd.reductions] ----------------------------------------------------------
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
namespace simd
{
  template <typename _Tp, typename _Ap, __reduction_binary_operation<_Tp> _BinaryOperation = plus<>>
    [[__gnu__::__always_inline__]]
    constexpr _Tp
    reduce(const basic_vec<_Tp, _Ap>& __x, _BinaryOperation __binary_op = {})
    { return __x._M_reduce(__binary_op); }

  template <typename _Tp, typename _Ap, __reduction_binary_operation<_Tp> _BinaryOperation = plus<>>
    [[__gnu__::__always_inline__]]
    constexpr _Tp
    reduce(const basic_vec<_Tp, _Ap>& __x, const typename basic_vec<_Tp, _Ap>::mask_type& __mask,
	   _BinaryOperation __binary_op = {}, type_identity_t<_Tp> __identity_element
	     = __default_identity_element<_Tp, _BinaryOperation>())
    { return reduce(__select_impl(__mask, __x, __identity_element), __binary_op); }

  template <totally_ordered _Tp, typename _Ap>
    [[__gnu__::__always_inline__]]
    constexpr _Tp
    reduce_min(const basic_vec<_Tp, _Ap>& __x) noexcept
    {
      return reduce(__x, []<typename _UV>(const _UV& __a, const _UV& __b) {
	       return __select_impl(__a < __b, __a, __b);
	     });
    }

  template <totally_ordered _Tp, typename _Ap>
    [[__gnu__::__always_inline__]]
    constexpr _Tp
    reduce_min(const basic_vec<_Tp, _Ap>& __x,
	       const typename basic_vec<_Tp, _Ap>::mask_type& __mask) noexcept
    {
      return reduce(__select_impl(__mask, __x, numeric_limits<_Tp>::max()),
		    []<typename _UV>(const _UV& __a, const _UV& __b) {
		      return __select_impl(__a < __b, __a, __b);
		    });
    }

  template <totally_ordered _Tp, typename _Ap>
    [[__gnu__::__always_inline__]]
    constexpr _Tp
    reduce_max(const basic_vec<_Tp, _Ap>& __x) noexcept
    {
      return reduce(__x, []<typename _UV>(const _UV& __a, const _UV& __b) {
	       return __select_impl(__a < __b, __b, __a);
	     });
    }

  template <totally_ordered _Tp, typename _Ap>
    [[__gnu__::__always_inline__]]
    constexpr _Tp
    reduce_max(const basic_vec<_Tp, _Ap>& __x,
	       const typename basic_vec<_Tp, _Ap>::mask_type& __mask) noexcept
    {
      return reduce(__select_impl(__mask, __x, numeric_limits<_Tp>::lowest()),
		    []<typename _UV>(const _UV& __a, const _UV& __b) {
		      return __select_impl(__a < __b, __b, __a);
		    });
    }
} // namespace simd
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std

#pragma GCC diagnostic pop
#endif // C++26
#endif // _GLIBCXX_SIMD_REDUCTIONS_H