99 lines
3.5 KiB
C++
99 lines
3.5 KiB
C++
// -*- C++ -*-
|
|
// -*-===----------------------------------------------------------------------===//
|
|
//
|
|
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
//
|
|
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
|
// See https://llvm.org/LICENSE.txt for license information.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef _PSTL_INTERNAL_OMP_PARALLEL_MERGE_H
|
|
#define _PSTL_INTERNAL_OMP_PARALLEL_MERGE_H
|
|
|
|
#include "util.h"
|
|
|
|
namespace __pstl
|
|
{
|
|
namespace __omp_backend
|
|
{
|
|
|
|
template <typename _RandomAccessIterator1, typename _RandomAccessIterator2, typename _RandomAccessIterator3,
|
|
typename _Compare, typename _LeafMerge>
|
|
void
|
|
__parallel_merge_body(std::size_t __size_x, std::size_t __size_y, _RandomAccessIterator1 __xs,
|
|
_RandomAccessIterator1 __xe, _RandomAccessIterator2 __ys, _RandomAccessIterator2 __ye,
|
|
_RandomAccessIterator3 __zs, _Compare __comp, _LeafMerge __leaf_merge)
|
|
{
|
|
|
|
if (__size_x + __size_y <= __omp_backend::__default_chunk_size)
|
|
{
|
|
__leaf_merge(__xs, __xe, __ys, __ye, __zs, __comp);
|
|
return;
|
|
}
|
|
|
|
_RandomAccessIterator1 __xm;
|
|
_RandomAccessIterator2 __ym;
|
|
|
|
if (__size_x < __size_y)
|
|
{
|
|
__ym = __ys + (__size_y / 2);
|
|
__xm = std::upper_bound(__xs, __xe, *__ym, __comp);
|
|
}
|
|
else
|
|
{
|
|
__xm = __xs + (__size_x / 2);
|
|
__ym = std::lower_bound(__ys, __ye, *__xm, __comp);
|
|
}
|
|
|
|
auto __zm = __zs + (__xm - __xs) + (__ym - __ys);
|
|
|
|
_PSTL_PRAGMA(omp task untied mergeable default(none)
|
|
firstprivate(__xs, __xm, __ys, __ym, __zs, __comp, __leaf_merge))
|
|
__pstl::__omp_backend::__parallel_merge_body(__xm - __xs, __ym - __ys, __xs, __xm, __ys, __ym, __zs, __comp,
|
|
__leaf_merge);
|
|
|
|
_PSTL_PRAGMA(omp task untied mergeable default(none)
|
|
firstprivate(__xm, __xe, __ym, __ye, __zm, __comp, __leaf_merge))
|
|
__pstl::__omp_backend::__parallel_merge_body(__xe - __xm, __ye - __ym, __xm, __xe, __ym, __ye, __zm, __comp,
|
|
__leaf_merge);
|
|
|
|
_PSTL_PRAGMA(omp taskwait)
|
|
}
|
|
|
|
template <class _ExecutionPolicy, typename _RandomAccessIterator1, typename _RandomAccessIterator2,
|
|
typename _RandomAccessIterator3, typename _Compare, typename _LeafMerge>
|
|
void
|
|
__parallel_merge(__pstl::__internal::__openmp_backend_tag, _ExecutionPolicy&& /*__exec*/, _RandomAccessIterator1 __xs,
|
|
_RandomAccessIterator1 __xe, _RandomAccessIterator2 __ys, _RandomAccessIterator2 __ye,
|
|
_RandomAccessIterator3 __zs, _Compare __comp, _LeafMerge __leaf_merge)
|
|
|
|
{
|
|
std::size_t __size_x = __xe - __xs;
|
|
std::size_t __size_y = __ye - __ys;
|
|
|
|
/*
|
|
* Run the merge in parallel by chunking it up. Use the smaller range (if any) as the iteration range, and the
|
|
* larger range as the search range.
|
|
*/
|
|
|
|
if (omp_in_parallel())
|
|
{
|
|
__pstl::__omp_backend::__parallel_merge_body(__size_x, __size_y, __xs, __xe, __ys, __ye, __zs, __comp,
|
|
__leaf_merge);
|
|
}
|
|
else
|
|
{
|
|
_PSTL_PRAGMA(omp parallel)
|
|
{
|
|
_PSTL_PRAGMA(omp single nowait)
|
|
__pstl::__omp_backend::__parallel_merge_body(__size_x, __size_y, __xs, __xe, __ys, __ye, __zs, __comp,
|
|
__leaf_merge);
|
|
}
|
|
}
|
|
}
|
|
|
|
} // namespace __omp_backend
|
|
} // namespace __pstl
|
|
#endif // _PSTL_INTERNAL_OMP_PARALLEL_MERGE_H
|