mirror of
https://github.com/llvm/llvm-project.git
synced 2025-04-18 19:36:38 +00:00
4baf1c03fa
This PR optimizes the performance of `std::ranges::rotate` for `vector<bool>::iterator`. The optimization yields a performance improvement of up to 2096x. Closes #64038.
244 lines
9.3 KiB
C++
244 lines
9.3 KiB
C++
//===----------------------------------------------------------------------===//
|
|
//
|
|
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
|
// See https://llvm.org/LICENSE.txt for license information.
|
|
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef _LIBCPP___ALGORITHM_ROTATE_H
|
|
#define _LIBCPP___ALGORITHM_ROTATE_H
|
|
|
|
#include <__algorithm/copy.h>
|
|
#include <__algorithm/copy_backward.h>
|
|
#include <__algorithm/iterator_operations.h>
|
|
#include <__algorithm/move.h>
|
|
#include <__algorithm/move_backward.h>
|
|
#include <__algorithm/swap_ranges.h>
|
|
#include <__config>
|
|
#include <__cstddef/size_t.h>
|
|
#include <__fwd/bit_reference.h>
|
|
#include <__iterator/iterator_traits.h>
|
|
#include <__memory/construct_at.h>
|
|
#include <__memory/pointer_traits.h>
|
|
#include <__type_traits/is_constant_evaluated.h>
|
|
#include <__type_traits/is_trivially_assignable.h>
|
|
#include <__utility/move.h>
|
|
#include <__utility/pair.h>
|
|
|
|
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
|
|
# pragma GCC system_header
|
|
#endif
|
|
|
|
_LIBCPP_PUSH_MACROS
|
|
#include <__undef_macros>
|
|
|
|
_LIBCPP_BEGIN_NAMESPACE_STD
|
|
|
|
template <class _AlgPolicy, class _ForwardIterator>
|
|
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator
|
|
__rotate_left(_ForwardIterator __first, _ForwardIterator __last) {
|
|
typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
|
|
using _Ops = _IterOps<_AlgPolicy>;
|
|
|
|
value_type __tmp = _Ops::__iter_move(__first);
|
|
_ForwardIterator __lm1 = std::__move<_AlgPolicy>(_Ops::next(__first), __last, __first).second;
|
|
*__lm1 = std::move(__tmp);
|
|
return __lm1;
|
|
}
|
|
|
|
template <class _AlgPolicy, class _BidirectionalIterator>
|
|
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _BidirectionalIterator
|
|
__rotate_right(_BidirectionalIterator __first, _BidirectionalIterator __last) {
|
|
typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
|
|
using _Ops = _IterOps<_AlgPolicy>;
|
|
|
|
_BidirectionalIterator __lm1 = _Ops::prev(__last);
|
|
value_type __tmp = _Ops::__iter_move(__lm1);
|
|
_BidirectionalIterator __fp1 = std::__move_backward<_AlgPolicy>(__first, __lm1, std::move(__last)).second;
|
|
*__first = std::move(__tmp);
|
|
return __fp1;
|
|
}
|
|
|
|
template <class _AlgPolicy, class _ForwardIterator>
|
|
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 _ForwardIterator
|
|
__rotate_forward(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last) {
|
|
_ForwardIterator __i = __middle;
|
|
while (true) {
|
|
_IterOps<_AlgPolicy>::iter_swap(__first, __i);
|
|
++__first;
|
|
if (++__i == __last)
|
|
break;
|
|
if (__first == __middle)
|
|
__middle = __i;
|
|
}
|
|
_ForwardIterator __r = __first;
|
|
if (__first != __middle) {
|
|
__i = __middle;
|
|
while (true) {
|
|
_IterOps<_AlgPolicy>::iter_swap(__first, __i);
|
|
++__first;
|
|
if (++__i == __last) {
|
|
if (__first == __middle)
|
|
break;
|
|
__i = __middle;
|
|
} else if (__first == __middle)
|
|
__middle = __i;
|
|
}
|
|
}
|
|
return __r;
|
|
}
|
|
|
|
template <typename _Integral>
|
|
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 _Integral __algo_gcd(_Integral __x, _Integral __y) {
|
|
do {
|
|
_Integral __t = __x % __y;
|
|
__x = __y;
|
|
__y = __t;
|
|
} while (__y);
|
|
return __x;
|
|
}
|
|
|
|
template <class _AlgPolicy, typename _RandomAccessIterator>
|
|
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 _RandomAccessIterator
|
|
__rotate_gcd(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last) {
|
|
typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
|
|
typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
|
|
using _Ops = _IterOps<_AlgPolicy>;
|
|
|
|
const difference_type __m1 = __middle - __first;
|
|
const difference_type __m2 = _Ops::distance(__middle, __last);
|
|
if (__m1 == __m2) {
|
|
std::__swap_ranges<_AlgPolicy>(__first, __middle, __middle, __last);
|
|
return __middle;
|
|
}
|
|
const difference_type __g = std::__algo_gcd(__m1, __m2);
|
|
for (_RandomAccessIterator __p = __first + __g; __p != __first;) {
|
|
value_type __t(_Ops::__iter_move(--__p));
|
|
_RandomAccessIterator __p1 = __p;
|
|
_RandomAccessIterator __p2 = __p1 + __m1;
|
|
do {
|
|
*__p1 = _Ops::__iter_move(__p2);
|
|
__p1 = __p2;
|
|
const difference_type __d = _Ops::distance(__p2, __last);
|
|
if (__m1 < __d)
|
|
__p2 += __m1;
|
|
else
|
|
__p2 = __first + (__m1 - __d);
|
|
} while (__p2 != __p);
|
|
*__p1 = std::move(__t);
|
|
}
|
|
return __first + __m2;
|
|
}
|
|
|
|
template <class _AlgPolicy, class _ForwardIterator>
|
|
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator
|
|
__rotate_impl(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last, std::forward_iterator_tag) {
|
|
typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
|
|
if (is_trivially_move_assignable<value_type>::value) {
|
|
if (_IterOps<_AlgPolicy>::next(__first) == __middle)
|
|
return std::__rotate_left<_AlgPolicy>(__first, __last);
|
|
}
|
|
return std::__rotate_forward<_AlgPolicy>(__first, __middle, __last);
|
|
}
|
|
|
|
template <class _AlgPolicy, class _BidirectionalIterator>
|
|
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _BidirectionalIterator __rotate_impl(
|
|
_BidirectionalIterator __first,
|
|
_BidirectionalIterator __middle,
|
|
_BidirectionalIterator __last,
|
|
bidirectional_iterator_tag) {
|
|
typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
|
|
if (is_trivially_move_assignable<value_type>::value) {
|
|
if (_IterOps<_AlgPolicy>::next(__first) == __middle)
|
|
return std::__rotate_left<_AlgPolicy>(__first, __last);
|
|
if (_IterOps<_AlgPolicy>::next(__middle) == __last)
|
|
return std::__rotate_right<_AlgPolicy>(__first, __last);
|
|
}
|
|
return std::__rotate_forward<_AlgPolicy>(__first, __middle, __last);
|
|
}
|
|
|
|
template <class _AlgPolicy, class _RandomAccessIterator>
|
|
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _RandomAccessIterator __rotate_impl(
|
|
_RandomAccessIterator __first,
|
|
_RandomAccessIterator __middle,
|
|
_RandomAccessIterator __last,
|
|
random_access_iterator_tag) {
|
|
typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
|
|
if (is_trivially_move_assignable<value_type>::value) {
|
|
if (_IterOps<_AlgPolicy>::next(__first) == __middle)
|
|
return std::__rotate_left<_AlgPolicy>(__first, __last);
|
|
if (_IterOps<_AlgPolicy>::next(__middle) == __last)
|
|
return std::__rotate_right<_AlgPolicy>(__first, __last);
|
|
return std::__rotate_gcd<_AlgPolicy>(__first, __middle, __last);
|
|
}
|
|
return std::__rotate_forward<_AlgPolicy>(__first, __middle, __last);
|
|
}
|
|
|
|
template <class _AlgPolicy, class _Iterator, class _Sentinel>
|
|
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_Iterator, _Iterator>
|
|
__rotate(_Iterator __first, _Iterator __middle, _Sentinel __last) {
|
|
using _Ret = pair<_Iterator, _Iterator>;
|
|
_Iterator __last_iter = _IterOps<_AlgPolicy>::next(__middle, __last);
|
|
|
|
if (__first == __middle)
|
|
return _Ret(__last_iter, __last_iter);
|
|
if (__middle == __last)
|
|
return _Ret(std::move(__first), std::move(__last_iter));
|
|
|
|
using _IterCategory = typename _IterOps<_AlgPolicy>::template __iterator_category<_Iterator>;
|
|
auto __result = std::__rotate_impl<_AlgPolicy>(std::move(__first), std::move(__middle), __last_iter, _IterCategory());
|
|
|
|
return _Ret(std::move(__result), std::move(__last_iter));
|
|
}
|
|
|
|
template <class, class _Cp>
|
|
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<__bit_iterator<_Cp, false>, __bit_iterator<_Cp, false> >
|
|
__rotate(__bit_iterator<_Cp, false> __first, __bit_iterator<_Cp, false> __middle, __bit_iterator<_Cp, false> __last) {
|
|
using _I1 = __bit_iterator<_Cp, false>;
|
|
using difference_type = typename _I1::difference_type;
|
|
difference_type __d1 = __middle - __first;
|
|
difference_type __d2 = __last - __middle;
|
|
_I1 __r = __first + __d2;
|
|
while (__d1 != 0 && __d2 != 0) {
|
|
if (__d1 <= __d2) {
|
|
if (__d1 <= __bit_array<_Cp>::capacity()) {
|
|
__bit_array<_Cp> __b(__d1);
|
|
std::copy(__first, __middle, __b.begin());
|
|
std::copy(__b.begin(), __b.end(), std::copy(__middle, __last, __first));
|
|
break;
|
|
} else {
|
|
__bit_iterator<_Cp, false> __mp = std::swap_ranges(__first, __middle, __middle);
|
|
__first = __middle;
|
|
__middle = __mp;
|
|
__d2 -= __d1;
|
|
}
|
|
} else {
|
|
if (__d2 <= __bit_array<_Cp>::capacity()) {
|
|
__bit_array<_Cp> __b(__d2);
|
|
std::copy(__middle, __last, __b.begin());
|
|
std::copy_backward(__b.begin(), __b.end(), std::copy_backward(__first, __middle, __last));
|
|
break;
|
|
} else {
|
|
__bit_iterator<_Cp, false> __mp = __first + __d2;
|
|
std::swap_ranges(__first, __mp, __middle);
|
|
__first = __mp;
|
|
__d1 -= __d2;
|
|
}
|
|
}
|
|
}
|
|
return std::make_pair(__r, __last);
|
|
}
|
|
|
|
template <class _ForwardIterator>
|
|
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
|
|
rotate(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last) {
|
|
return std::__rotate<_ClassicAlgPolicy>(std::move(__first), std::move(__middle), std::move(__last)).first;
|
|
}
|
|
|
|
_LIBCPP_END_NAMESPACE_STD
|
|
|
|
_LIBCPP_POP_MACROS
|
|
|
|
#endif // _LIBCPP___ALGORITHM_ROTATE_H
|