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update libcxx to LLVM 16.0.1

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This commit is contained in:
Andrew Kelley
2023-04-05 23:22:29 -07:00
parent f289277599
commit fc9ab4144c
8 changed files with 192 additions and 461 deletions
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578
lib/libcxx/include/__algorithm/sort.h vendored
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@@ -11,15 +11,10 @@
#include <__algorithm/comp.h>
#include <__algorithm/comp_ref_type.h>
#include <__algorithm/iter_swap.h>
#include <__algorithm/iterator_operations.h>
#include <__algorithm/min_element.h>
#include <__algorithm/partial_sort.h>
#include <__algorithm/unwrap_iter.h>
#include <__assert>
#include <__bit/blsr.h>
#include <__bit/countl.h>
#include <__bit/countr.h>
#include <__config>
#include <__debug>
#include <__debug_utils/randomize_range.h>
@@ -28,10 +23,11 @@
#include <__iterator/iterator_traits.h>
#include <__memory/destruct_n.h>
#include <__memory/unique_ptr.h>
#include <__type_traits/conditional.h>
#include <__type_traits/is_arithmetic.h>
#include <__type_traits/is_trivially_copy_assignable.h>
#include <__type_traits/is_trivially_copy_constructible.h>
#include <__utility/move.h>
#include <__utility/pair.h>
#include <bit>
#include <climits>
#include <cstdint>
@@ -132,7 +128,8 @@ template <class _AlgPolicy, class _Compare, class _ForwardIterator>
_LIBCPP_HIDE_FROM_ABI
unsigned __sort4(_ForwardIterator __x1, _ForwardIterator __x2, _ForwardIterator __x3, _ForwardIterator __x4,
_Compare __c) {
using _Ops = _IterOps<_AlgPolicy>;
using _Ops = _IterOps<_AlgPolicy>;
unsigned __r = std::__sort3<_AlgPolicy, _Compare>(__x1, __x2, __x3, __c);
if (__c(*__x4, *__x3)) {
_Ops::iter_swap(__x3, __x4);
@@ -187,7 +184,7 @@ _LIBCPP_HIDE_FROM_ABI unsigned __sort5_wrap_policy(
_Compare __c) {
using _WrappedComp = typename _WrapAlgPolicy<_AlgPolicy, _Compare>::type;
_WrappedComp __wrapped_comp(__c);
return std::__sort5<_WrappedComp, _ForwardIterator>(
return std::__sort5<_WrappedComp>(
std::move(__x1), std::move(__x2), std::move(__x3), std::move(__x4), std::move(__x5), __wrapped_comp);
}
@@ -212,13 +209,6 @@ using __use_branchless_sort =
integral_constant<bool, __is_cpp17_contiguous_iterator<_Iter>::value && sizeof(_Tp) <= sizeof(void*) &&
is_arithmetic<_Tp>::value && __is_simple_comparator<_Compare>::value>;
namespace __detail {
// Size in bits for the bitset in use.
enum { __block_size = sizeof(uint64_t) * 8 };
} // namespace __detail
// Ensures that __c(*__x, *__y) is true by swapping *__x and *__y if necessary.
template <class _Compare, class _RandomAccessIterator>
inline _LIBCPP_HIDE_FROM_ABI void __cond_swap(_RandomAccessIterator __x, _RandomAccessIterator __y, _Compare __c) {
@@ -278,15 +268,10 @@ __sort4_maybe_branchless(_RandomAccessIterator __x1, _RandomAccessIterator __x2,
std::__sort4<_AlgPolicy, _Compare>(__x1, __x2, __x3, __x4, __c);
}
template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
template <class, class _Compare, class _RandomAccessIterator>
inline _LIBCPP_HIDE_FROM_ABI __enable_if_t<__use_branchless_sort<_Compare, _RandomAccessIterator>::value, void>
__sort5_maybe_branchless(
_RandomAccessIterator __x1,
_RandomAccessIterator __x2,
_RandomAccessIterator __x3,
_RandomAccessIterator __x4,
_RandomAccessIterator __x5,
_Compare __c) {
__sort5_maybe_branchless(_RandomAccessIterator __x1, _RandomAccessIterator __x2, _RandomAccessIterator __x3,
_RandomAccessIterator __x4, _RandomAccessIterator __x5, _Compare __c) {
std::__cond_swap<_Compare>(__x1, __x2, __c);
std::__cond_swap<_Compare>(__x4, __x5, __c);
std::__partially_sorted_swap<_Compare>(__x3, __x4, __x5, __c);
@@ -315,48 +300,34 @@ _LIBCPP_CONSTEXPR_SINCE_CXX14 void __selection_sort(_BidirectionalIterator __fir
}
}
// Sort the iterator range [__first, __last) using the comparator __comp using
// the insertion sort algorithm.
template <class _AlgPolicy, class _Compare, class _BidirectionalIterator>
_LIBCPP_HIDE_FROM_ABI
void __insertion_sort(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp) {
using _Ops = _IterOps<_AlgPolicy>;
typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
if (__first == __last)
return;
_BidirectionalIterator __i = __first;
for (++__i; __i != __last; ++__i) {
_BidirectionalIterator __j = __i;
--__j;
if (__comp(*__i, *__j)) {
value_type __t(_Ops::__iter_move(__i));
_BidirectionalIterator __k = __j;
__j = __i;
do {
if (__first != __last) {
_BidirectionalIterator __i = __first;
for (++__i; __i != __last; ++__i) {
_BidirectionalIterator __j = __i;
value_type __t(_Ops::__iter_move(__j));
for (_BidirectionalIterator __k = __i; __k != __first && __comp(__t, *--__k); --__j)
*__j = _Ops::__iter_move(__k);
__j = __k;
} while (__j != __first && __comp(__t, *--__k));
*__j = std::move(__t);
}
}
}
// Sort the iterator range [__first, __last) using the comparator __comp using
// the insertion sort algorithm. Insertion sort has two loops, outer and inner.
// The implementation below has not bounds check (unguarded) for the inner loop.
// Assumes that there is an element in the position (__first - 1) and that each
// element in the input range is greater or equal to the element at __first - 1.
template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
_LIBCPP_HIDE_FROM_ABI void
__insertion_sort_unguarded(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
_LIBCPP_HIDE_FROM_ABI
void __insertion_sort_3(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
using _Ops = _IterOps<_AlgPolicy>;
typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
if (__first == __last)
return;
for (_RandomAccessIterator __i = __first + difference_type(1); __i != __last; ++__i) {
_RandomAccessIterator __j = __i - difference_type(1);
_RandomAccessIterator __j = __first + difference_type(2);
std::__sort3_maybe_branchless<_AlgPolicy, _Compare>(__first, __first + difference_type(1), __j, __comp);
for (_RandomAccessIterator __i = __j + difference_type(1); __i != __last; ++__i) {
if (__comp(*__i, *__j)) {
value_type __t(_Ops::__iter_move(__i));
_RandomAccessIterator __k = __j;
@@ -364,9 +335,10 @@ __insertion_sort_unguarded(_RandomAccessIterator __first, _RandomAccessIterator
do {
*__j = _Ops::__iter_move(__k);
__j = __k;
} while (__comp(__t, *--__k)); // No need for bounds check due to the assumption stated above.
} while (__j != __first && __comp(__t, *--__k));
*__j = std::move(__t);
}
__j = __i;
}
}
@@ -387,7 +359,7 @@ _LIBCPP_HIDDEN bool __insertion_sort_incomplete(
return true;
case 2:
if (__comp(*--__last, *__first))
_Ops::iter_swap(__first, __last);
_IterOps<_AlgPolicy>::iter_swap(__first, __last);
return true;
case 3:
std::__sort3_maybe_branchless<_AlgPolicy, _Compare>(__first, __first + difference_type(1), --__last, __comp);
@@ -456,336 +428,17 @@ void __insertion_sort_move(_BidirectionalIterator __first1, _BidirectionalIterat
}
}
template <class _AlgPolicy, class _RandomAccessIterator>
inline _LIBCPP_HIDE_FROM_ABI void __swap_bitmap_pos(
_RandomAccessIterator __first, _RandomAccessIterator __last, uint64_t& __left_bitset, uint64_t& __right_bitset) {
template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
void __introsort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
typename iterator_traits<_RandomAccessIterator>::difference_type __depth) {
using _Ops = _IterOps<_AlgPolicy>;
typedef typename std::iterator_traits<_RandomAccessIterator>::difference_type difference_type;
// Swap one pair on each iteration as long as both bitsets have at least one
// element for swapping.
while (__left_bitset != 0 && __right_bitset != 0) {
difference_type tz_left = __libcpp_ctz(__left_bitset);
__left_bitset = __libcpp_blsr(__left_bitset);
difference_type tz_right = __libcpp_ctz(__right_bitset);
__right_bitset = __libcpp_blsr(__right_bitset);
_Ops::iter_swap(__first + tz_left, __last - tz_right);
}
}
template <class _Compare,
class _RandomAccessIterator,
class _ValueType = typename iterator_traits<_RandomAccessIterator>::value_type>
inline _LIBCPP_HIDE_FROM_ABI void
__populate_left_bitset(_RandomAccessIterator __first, _Compare __comp, _ValueType& __pivot, uint64_t& __left_bitset) {
// Possible vectorization. With a proper "-march" flag, the following loop
// will be compiled into a set of SIMD instructions.
_RandomAccessIterator __iter = __first;
for (int __j = 0; __j < __detail::__block_size;) {
bool __comp_result = !__comp(*__iter, __pivot);
__left_bitset |= (static_cast<uint64_t>(__comp_result) << __j);
__j++;
++__iter;
}
}
template <class _Compare,
class _RandomAccessIterator,
class _ValueType = typename iterator_traits<_RandomAccessIterator>::value_type>
inline _LIBCPP_HIDE_FROM_ABI void
__populate_right_bitset(_RandomAccessIterator __lm1, _Compare __comp, _ValueType& __pivot, uint64_t& __right_bitset) {
// Possible vectorization. With a proper "-march" flag, the following loop
// will be compiled into a set of SIMD instructions.
_RandomAccessIterator __iter = __lm1;
for (int __j = 0; __j < __detail::__block_size;) {
bool __comp_result = __comp(*__iter, __pivot);
__right_bitset |= (static_cast<uint64_t>(__comp_result) << __j);
__j++;
--__iter;
}
}
template <class _AlgPolicy,
class _Compare,
class _RandomAccessIterator,
class _ValueType = typename iterator_traits<_RandomAccessIterator>::value_type>
inline _LIBCPP_HIDE_FROM_ABI void __bitset_partition_partial_blocks(
_RandomAccessIterator& __first,
_RandomAccessIterator& __lm1,
_Compare __comp,
_ValueType& __pivot,
uint64_t& __left_bitset,
uint64_t& __right_bitset) {
typedef typename std::iterator_traits<_RandomAccessIterator>::difference_type difference_type;
difference_type __remaining_len = __lm1 - __first + 1;
difference_type __l_size;
difference_type __r_size;
if (__left_bitset == 0 && __right_bitset == 0) {
__l_size = __remaining_len / 2;
__r_size = __remaining_len - __l_size;
} else if (__left_bitset == 0) {
// We know at least one side is a full block.
__l_size = __remaining_len - __detail::__block_size;
__r_size = __detail::__block_size;
} else { // if (__right_bitset == 0)
__l_size = __detail::__block_size;
__r_size = __remaining_len - __detail::__block_size;
}
// Record the comparison outcomes for the elements currently on the left side.
if (__left_bitset == 0) {
_RandomAccessIterator __iter = __first;
for (int j = 0; j < __l_size; j++) {
bool __comp_result = !__comp(*__iter, __pivot);
__left_bitset |= (static_cast<uint64_t>(__comp_result) << j);
++__iter;
}
}
// Record the comparison outcomes for the elements currently on the right
// side.
if (__right_bitset == 0) {
_RandomAccessIterator __iter = __lm1;
for (int j = 0; j < __r_size; j++) {
bool __comp_result = __comp(*__iter, __pivot);
__right_bitset |= (static_cast<uint64_t>(__comp_result) << j);
--__iter;
}
}
std::__swap_bitmap_pos<_AlgPolicy, _RandomAccessIterator>(__first, __lm1, __left_bitset, __right_bitset);
__first += (__left_bitset == 0) ? __l_size : 0;
__lm1 -= (__right_bitset == 0) ? __r_size : 0;
}
template <class _AlgPolicy, class _RandomAccessIterator>
inline _LIBCPP_HIDE_FROM_ABI void __swap_bitmap_pos_within(
_RandomAccessIterator& __first, _RandomAccessIterator& __lm1, uint64_t& __left_bitset, uint64_t& __right_bitset) {
using _Ops = _IterOps<_AlgPolicy>;
typedef typename std::iterator_traits<_RandomAccessIterator>::difference_type difference_type;
if (__left_bitset) {
// Swap within the left side. Need to find set positions in the reverse
// order.
while (__left_bitset != 0) {
difference_type __tz_left = __detail::__block_size - 1 - __libcpp_clz(__left_bitset);
__left_bitset &= (static_cast<uint64_t>(1) << __tz_left) - 1;
_RandomAccessIterator it = __first + __tz_left;
if (it != __lm1) {
_Ops::iter_swap(it, __lm1);
}
--__lm1;
}
__first = __lm1 + difference_type(1);
} else if (__right_bitset) {
// Swap within the right side. Need to find set positions in the reverse
// order.
while (__right_bitset != 0) {
difference_type __tz_right = __detail::__block_size - 1 - __libcpp_clz(__right_bitset);
__right_bitset &= (static_cast<uint64_t>(1) << __tz_right) - 1;
_RandomAccessIterator it = __lm1 - __tz_right;
if (it != __first) {
_Ops::iter_swap(it, __first);
}
++__first;
}
}
}
// Partition [__first, __last) using the comparator __comp. *__first has the
// chosen pivot. Elements that are equivalent are kept to the left of the
// pivot. Returns the iterator for the pivot and a bool value which is true if
// the provided range is already sorted, false otherwise. We assume that the
// length of the range is at least three elements.
//
// __bitset_partition uses bitsets for storing outcomes of the comparisons
// between the pivot and other elements.
template <class _AlgPolicy, class _RandomAccessIterator, class _Compare>
_LIBCPP_HIDE_FROM_ABI std::pair<_RandomAccessIterator, bool>
__bitset_partition(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
using _Ops = _IterOps<_AlgPolicy>;
typedef typename std::iterator_traits<_RandomAccessIterator>::value_type value_type;
typedef typename std::iterator_traits<_RandomAccessIterator>::difference_type difference_type;
_LIBCPP_ASSERT(__last - __first >= difference_type(3), "");
_RandomAccessIterator __begin = __first;
value_type __pivot(_Ops::__iter_move(__first));
// Find the first element greater than the pivot.
if (__comp(__pivot, *(__last - difference_type(1)))) {
// Not guarded since we know the last element is greater than the pivot.
while (!__comp(__pivot, *++__first)) {
}
} else {
while (++__first < __last && !__comp(__pivot, *__first)) {
}
}
// Find the last element less than or equal to the pivot.
if (__first < __last) {
// It will be always guarded because __introsort will do the median-of-three
// before calling this.
while (__comp(__pivot, *--__last)) {
}
}
// If the first element greater than the pivot is at or after the
// last element less than or equal to the pivot, then we have covered the
// entire range without swapping elements. This implies the range is already
// partitioned.
bool __already_partitioned = __first >= __last;
if (!__already_partitioned) {
_Ops::iter_swap(__first, __last);
++__first;
}
// In [__first, __last) __last is not inclusive. From now on, it uses last
// minus one to be inclusive on both sides.
_RandomAccessIterator __lm1 = __last - difference_type(1);
uint64_t __left_bitset = 0;
uint64_t __right_bitset = 0;
// Reminder: length = __lm1 - __first + 1.
while (__lm1 - __first >= 2 * __detail::__block_size - 1) {
// Record the comparison outcomes for the elements currently on the left
// side.
if (__left_bitset == 0)
std::__populate_left_bitset<_Compare>(__first, __comp, __pivot, __left_bitset);
// Record the comparison outcomes for the elements currently on the right
// side.
if (__right_bitset == 0)
std::__populate_right_bitset<_Compare>(__lm1, __comp, __pivot, __right_bitset);
// Swap the elements recorded to be the candidates for swapping in the
// bitsets.
std::__swap_bitmap_pos<_AlgPolicy, _RandomAccessIterator>(__first, __lm1, __left_bitset, __right_bitset);
// Only advance the iterator if all the elements that need to be moved to
// other side were moved.
__first += (__left_bitset == 0) ? difference_type(__detail::__block_size) : difference_type(0);
__lm1 -= (__right_bitset == 0) ? difference_type(__detail::__block_size) : difference_type(0);
}
// Now, we have a less-than a block worth of elements on at least one of the
// sides.
std::__bitset_partition_partial_blocks<_AlgPolicy, _Compare>(
__first, __lm1, __comp, __pivot, __left_bitset, __right_bitset);
// At least one the bitsets would be empty. For the non-empty one, we need to
// properly partition the elements that appear within that bitset.
std::__swap_bitmap_pos_within<_AlgPolicy>(__first, __lm1, __left_bitset, __right_bitset);
// Move the pivot to its correct position.
_RandomAccessIterator __pivot_pos = __first - difference_type(1);
if (__begin != __pivot_pos) {
*__begin = _Ops::__iter_move(__pivot_pos);
}
*__pivot_pos = std::move(__pivot);
return std::make_pair(__pivot_pos, __already_partitioned);
}
// Partition [__first, __last) using the comparator __comp. *__first has the
// chosen pivot. Elements that are equivalent are kept to the right of the
// pivot. Returns the iterator for the pivot and a bool value which is true if
// the provided range is already sorted, false otherwise. We assume that the
// length of the range is at least three elements.
template <class _AlgPolicy, class _RandomAccessIterator, class _Compare>
_LIBCPP_HIDE_FROM_ABI std::pair<_RandomAccessIterator, bool>
__partition_with_equals_on_right(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
using _Ops = _IterOps<_AlgPolicy>;
typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
typedef typename std::iterator_traits<_RandomAccessIterator>::value_type value_type;
_LIBCPP_ASSERT(__last - __first >= difference_type(3), "");
_RandomAccessIterator __begin = __first;
value_type __pivot(_Ops::__iter_move(__first));
// Find the first element greater or equal to the pivot. It will be always
// guarded because __introsort will do the median-of-three before calling
// this.
while (__comp(*++__first, __pivot))
;
// Find the last element less than the pivot.
if (__begin == __first - difference_type(1)) {
while (__first < __last && !__comp(*--__last, __pivot))
;
} else {
// Guarded.
while (!__comp(*--__last, __pivot))
;
}
// If the first element greater than or equal to the pivot is at or after the
// last element less than the pivot, then we have covered the entire range
// without swapping elements. This implies the range is already partitioned.
bool __already_partitioned = __first >= __last;
// Go through the remaining elements. Swap pairs of elements (one to the
// right of the pivot and the other to left of the pivot) that are not on the
// correct side of the pivot.
while (__first < __last) {
_Ops::iter_swap(__first, __last);
while (__comp(*++__first, __pivot))
;
while (!__comp(*--__last, __pivot))
;
}
// Move the pivot to its correct position.
_RandomAccessIterator __pivot_pos = __first - difference_type(1);
if (__begin != __pivot_pos) {
*__begin = _Ops::__iter_move(__pivot_pos);
}
*__pivot_pos = std::move(__pivot);
return std::make_pair(__pivot_pos, __already_partitioned);
}
// Similar to the above function. Elements equivalent to the pivot are put to
// the left of the pivot. Returns the iterator to the pivot element.
template <class _AlgPolicy, class _RandomAccessIterator, class _Compare>
_LIBCPP_HIDE_FROM_ABI _RandomAccessIterator
__partition_with_equals_on_left(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
using _Ops = _IterOps<_AlgPolicy>;
typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
typedef typename std::iterator_traits<_RandomAccessIterator>::value_type value_type;
_RandomAccessIterator __begin = __first;
value_type __pivot(_Ops::__iter_move(__first));
if (__comp(__pivot, *(__last - difference_type(1)))) {
// Guarded.
while (!__comp(__pivot, *++__first)) {
}
} else {
while (++__first < __last && !__comp(__pivot, *__first)) {
}
}
if (__first < __last) {
// It will be always guarded because __introsort will do the
// median-of-three before calling this.
while (__comp(__pivot, *--__last)) {
}
}
while (__first < __last) {
_Ops::iter_swap(__first, __last);
while (!__comp(__pivot, *++__first))
;
while (__comp(__pivot, *--__last))
;
}
_RandomAccessIterator __pivot_pos = __first - difference_type(1);
if (__begin != __pivot_pos) {
*__begin = _Ops::__iter_move(__pivot_pos);
}
*__pivot_pos = std::move(__pivot);
return __first;
}
// The main sorting function. Implements introsort combined with other ideas:
// - option of using block quick sort for partitioning,
// - guarded and unguarded insertion sort for small lengths,
// - Tuckey's ninther technique for computing the pivot,
// - check on whether partition was not required.
// The implementation is partly based on Orson Peters' pattern-defeating
// quicksort, published at: <https://github.com/orlp/pdqsort>.
template <class _AlgPolicy, class _Compare, class _RandomAccessIterator, bool _UseBitSetPartition>
void __introsort(_RandomAccessIterator __first,
_RandomAccessIterator __last,
_Compare __comp,
typename iterator_traits<_RandomAccessIterator>::difference_type __depth,
bool __leftmost = true) {
using _Ops = _IterOps<_AlgPolicy>;
typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
using _Comp_ref = __comp_ref_type<_Compare>;
// Upper bound for using insertion sort for sorting.
_LIBCPP_CONSTEXPR difference_type __limit = 24;
// Lower bound for using Tuckey's ninther technique for median computation.
_LIBCPP_CONSTEXPR difference_type __ninther_threshold = 128;
typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
const difference_type __limit =
is_trivially_copy_constructible<value_type>::value && is_trivially_copy_assignable<value_type>::value ? 30 : 6;
while (true) {
__restart:
difference_type __len = __last - __first;
switch (__len) {
case 0:
@@ -793,7 +446,7 @@ void __introsort(_RandomAccessIterator __first,
return;
case 2:
if (__comp(*--__last, *__first))
_Ops::iter_swap(__first, __last);
_IterOps<_AlgPolicy>::iter_swap(__first, __last);
return;
case 3:
std::__sort3_maybe_branchless<_AlgPolicy, _Compare>(__first, __first + difference_type(1), --__last, __comp);
@@ -808,60 +461,127 @@ void __introsort(_RandomAccessIterator __first,
--__last, __comp);
return;
}
// Use insertion sort if the length of the range is below the specified limit.
if (__len < __limit) {
if (__leftmost) {
std::__insertion_sort<_AlgPolicy, _Compare>(__first, __last, __comp);
} else {
std::__insertion_sort_unguarded<_AlgPolicy, _Compare>(__first, __last, __comp);
}
if (__len <= __limit) {
std::__insertion_sort_3<_AlgPolicy, _Compare>(__first, __last, __comp);
return;
}
// __len > 5
if (__depth == 0) {
// Fallback to heap sort as Introsort suggests.
std::__partial_sort<_AlgPolicy, _Compare>(__first, __last, __last, __comp);
return;
}
--__depth;
_RandomAccessIterator __m = __first;
_RandomAccessIterator __lm1 = __last;
--__lm1;
unsigned __n_swaps;
{
difference_type __half_len = __len / 2;
// Use Tuckey's ninther technique or median of 3 for pivot selection
// depending on the length of the range being sorted.
if (__len > __ninther_threshold) {
std::__sort3<_AlgPolicy, _Compare>(__first, __first + __half_len, __last - difference_type(1), __comp);
std::__sort3<_AlgPolicy, _Compare>(
__first + difference_type(1), __first + (__half_len - 1), __last - difference_type(2), __comp);
std::__sort3<_AlgPolicy, _Compare>(
__first + difference_type(2), __first + (__half_len + 1), __last - difference_type(3), __comp);
std::__sort3<_AlgPolicy, _Compare>(
__first + (__half_len - 1), __first + __half_len, __first + (__half_len + 1), __comp);
_Ops::iter_swap(__first, __first + __half_len);
difference_type __delta;
if (__len >= 1000) {
__delta = __len / 2;
__m += __delta;
__delta /= 2;
__n_swaps = std::__sort5_wrap_policy<_AlgPolicy, _Compare>(
__first, __first + __delta, __m, __m + __delta, __lm1, __comp);
} else {
std::__sort3<_AlgPolicy, _Compare>(__first + __half_len, __first, __last - difference_type(1), __comp);
__delta = __len / 2;
__m += __delta;
__n_swaps = std::__sort3<_AlgPolicy, _Compare>(__first, __m, __lm1, __comp);
}
}
// The elements to the left of the current iterator range are already
// sorted. If the current iterator range to be sorted is not the
// leftmost part of the entire iterator range and the pivot is same as
// the highest element in the range to the left, then we know that all
// the elements in the range [first, pivot] would be equal to the pivot,
// assuming the equal elements are put on the left side when
// partitioned. This also means that we do not need to sort the left
// side of the partition.
if (!__leftmost && !__comp(*(__first - difference_type(1)), *__first)) {
__first = std::__partition_with_equals_on_left<_AlgPolicy, _RandomAccessIterator, _Comp_ref>(
__first, __last, _Comp_ref(__comp));
continue;
// *__m is median
// partition [__first, __m) < *__m and *__m <= [__m, __last)
// (this inhibits tossing elements equivalent to __m around unnecessarily)
_RandomAccessIterator __i = __first;
_RandomAccessIterator __j = __lm1;
// j points beyond range to be tested, *__m is known to be <= *__lm1
// The search going up is known to be guarded but the search coming down isn't.
// Prime the downward search with a guard.
if (!__comp(*__i, *__m)) // if *__first == *__m
{
// *__first == *__m, *__first doesn't go in first part
// manually guard downward moving __j against __i
while (true) {
if (__i == --__j) {
// *__first == *__m, *__m <= all other elements
// Parition instead into [__first, __i) == *__first and *__first < [__i, __last)
++__i; // __first + 1
__j = __last;
if (!__comp(*__first, *--__j)) // we need a guard if *__first == *(__last-1)
{
while (true) {
if (__i == __j)
return; // [__first, __last) all equivalent elements
if (__comp(*__first, *__i)) {
_Ops::iter_swap(__i, __j);
++__n_swaps;
++__i;
break;
}
++__i;
}
}
// [__first, __i) == *__first and *__first < [__j, __last) and __j == __last - 1
if (__i == __j)
return;
while (true) {
while (!__comp(*__first, *__i))
++__i;
while (__comp(*__first, *--__j))
;
if (__i >= __j)
break;
_Ops::iter_swap(__i, __j);
++__n_swaps;
++__i;
}
// [__first, __i) == *__first and *__first < [__i, __last)
// The first part is sorted, sort the second part
// std::__sort<_Compare>(__i, __last, __comp);
__first = __i;
goto __restart;
}
if (__comp(*__j, *__m)) {
_Ops::iter_swap(__i, __j);
++__n_swaps;
break; // found guard for downward moving __j, now use unguarded partition
}
}
}
// It is known that *__i < *__m
++__i;
// j points beyond range to be tested, *__m is known to be <= *__lm1
// if not yet partitioned...
if (__i < __j) {
// known that *(__i - 1) < *__m
// known that __i <= __m
while (true) {
// __m still guards upward moving __i
while (__comp(*__i, *__m))
++__i;
// It is now known that a guard exists for downward moving __j
while (!__comp(*--__j, *__m))
;
if (__i > __j)
break;
_Ops::iter_swap(__i, __j);
++__n_swaps;
// It is known that __m != __j
// If __m just moved, follow it
if (__m == __i)
__m = __j;
++__i;
}
}
// [__first, __i) < *__m and *__m <= [__i, __last)
if (__i != __m && __comp(*__m, *__i)) {
_Ops::iter_swap(__i, __m);
++__n_swaps;
}
// Use bitset partition only if asked for.
auto __ret =
_UseBitSetPartition
? std::__bitset_partition<_AlgPolicy, _RandomAccessIterator, _Compare>(__first, __last, __comp)
: std::__partition_with_equals_on_right<_AlgPolicy, _RandomAccessIterator, _Compare>(__first, __last, __comp);
_RandomAccessIterator __i = __ret.first;
// [__first, __i) < *__i and *__i <= [__i+1, __last)
// If we were given a perfect partition, see if insertion sort is quick...
if (__ret.second) {
if (__n_swaps == 0) {
using _WrappedComp = typename _WrapAlgPolicy<_AlgPolicy, _Compare>::type;
_WrappedComp __wrapped_comp(__comp);
bool __fs = std::__insertion_sort_incomplete<_WrappedComp>(__first, __i, __wrapped_comp);
@@ -877,11 +597,14 @@ void __introsort(_RandomAccessIterator __first,
}
}
}
// Sort the left partiton recursively and the right partition with tail recursion elimination.
std::__introsort<_AlgPolicy, _Compare, _RandomAccessIterator, _UseBitSetPartition>(
__first, __i, __comp, __depth, __leftmost);
__leftmost = false;
__first = ++__i;
// sort smaller range with recursive call and larger with tail recursion elimination
if (__i - __first < __last - __i) {
std::__introsort<_AlgPolicy, _Compare>(__first, __i, __comp, __depth);
__first = ++__i;
} else {
std::__introsort<_AlgPolicy, _Compare>(__i + difference_type(1), __last, __comp, __depth);
__last = __i;
}
}
}
@@ -913,14 +636,7 @@ _LIBCPP_HIDDEN void __sort(_RandomAccessIterator __first, _RandomAccessIterator
using _AlgPolicy = typename _Unwrap::_AlgPolicy;
using _Compare = typename _Unwrap::_Comp;
_Compare __comp = _Unwrap::__get_comp(__wrapped_comp);
// Only use bitset partitioning for arithmetic types. We should also check
// that the default comparator is in use so that we are sure that there are no
// branches in the comparator.
std::__introsort<_AlgPolicy,
_Compare,
_RandomAccessIterator,
__use_branchless_sort<_Compare, _RandomAccessIterator>::value>(
__first, __last, __comp, __depth_limit);
std::__introsort<_AlgPolicy, _Compare>(__first, __last, __comp, __depth_limit);
}
template <class _Compare, class _Tp>