4fc5b6d8c4
This patch optimizes how `for_each` iterates over trees by using recursion and storing pointers to the next nodes on the stack. This avoids pointer chasing through the `__parent_` pointer, reducing cache misses. It also makes use of the compiler being able tail-call optimize the recursive function, removing back-tracking the iterators have to do. ``` Benchmark old new Difference % Difference -------------------------------------------------- -------------- -------------- ------------ -------------- rng::for_each(map<int>)/32 35.19 26.67 -8.52 -24.21% rng::for_each(map<int>)/50 64.13 40.68 -23.45 -36.57% rng::for_each(map<int>)/8 5.06 6.49 1.43 28.21% rng::for_each(map<int>)/8192 22893.89 9266.68 -13627.21 -59.52% rng::for_each(map<int>::iterator)/32 35.51 26.88 -8.63 -24.31% rng::for_each(map<int>::iterator)/50 64.39 41.24 -23.15 -35.95% rng::for_each(map<int>::iterator)/8 5.12 5.93 0.81 15.80% rng::for_each(map<int>::iterator)/8192 21283.14 9736.83 -11546.31 -54.25% rng::for_each(multimap<int>)/32 35.22 26.61 -8.61 -24.45% rng::for_each(multimap<int>)/50 64.10 40.07 -24.03 -37.49% rng::for_each(multimap<int>)/8 5.08 6.69 1.61 31.70% rng::for_each(multimap<int>)/8192 23130.44 9026.16 -14104.28 -60.98% rng::for_each(multimap<int>::iterator)/32 35.40 25.08 -10.32 -29.15% rng::for_each(multimap<int>::iterator)/50 64.19 38.15 -26.04 -40.56% rng::for_each(multimap<int>::iterator)/8 5.04 5.25 0.22 4.31% rng::for_each(multimap<int>::iterator)/8192 22875.97 9392.08 -13483.89 -58.94% rng::for_each(multiset<int>)/32 35.82 27.11 -8.72 -24.33% rng::for_each(multiset<int>)/50 62.92 41.59 -21.32 -33.89% rng::for_each(multiset<int>)/8 4.79 6.79 2.00 41.70% rng::for_each(multiset<int>)/8192 22642.68 9280.95 -13361.73 -59.01% rng::for_each(multiset<int>::iterator)/32 35.76 26.71 -9.04 -25.28% rng::for_each(multiset<int>::iterator)/50 63.44 39.00 -24.44 -38.53% rng::for_each(multiset<int>::iterator)/8 4.90 5.21 0.30 6.18% rng::for_each(multiset<int>::iterator)/8192 19930.45 9867.60 -10062.85 -50.49% rng::for_each(set<int>)/32 35.90 27.30 -8.60 -23.96% rng::for_each(set<int>)/50 63.15 40.75 -22.40 -35.47% rng::for_each(set<int>)/8 4.77 6.83 2.06 43.23% rng::for_each(set<int>)/8192 20262.77 9381.57 -10881.20 -53.70% rng::for_each(set<int>::iterator)/32 36.02 26.42 -9.60 -26.64% rng::for_each(set<int>::iterator)/50 63.29 37.97 -25.32 -40.01% rng::for_each(set<int>::iterator)/8 4.72 5.22 0.50 10.50% rng::for_each(set<int>::iterator)/8192 20041.91 9831.91 -10210.00 -50.94% ```
60 lines
2.2 KiB
C++
60 lines
2.2 KiB
C++
// -*- 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_FOR_EACH_H
|
|
#define _LIBCPP___ALGORITHM_FOR_EACH_H
|
|
|
|
#include <__algorithm/for_each_segment.h>
|
|
#include <__algorithm/specialized_algorithms.h>
|
|
#include <__config>
|
|
#include <__functional/identity.h>
|
|
#include <__iterator/segmented_iterator.h>
|
|
#include <__type_traits/invoke.h>
|
|
#include <__type_traits/is_same.h>
|
|
|
|
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
|
|
# pragma GCC system_header
|
|
#endif
|
|
|
|
_LIBCPP_BEGIN_NAMESPACE_STD
|
|
|
|
template <class _InputIterator, class _Sent, class _Func, class _Proj>
|
|
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _InputIterator
|
|
__for_each(_InputIterator __first, _Sent __last, _Func& __func, _Proj& __proj) {
|
|
#ifndef _LIBCPP_CXX03_LANG
|
|
if constexpr (using _SpecialAlg =
|
|
__specialized_algorithm<_Algorithm::__for_each, __iterator_pair<_InputIterator, _Sent>>;
|
|
_SpecialAlg::__has_algorithm) {
|
|
_SpecialAlg()(__first, __last, __func, __proj);
|
|
return __last;
|
|
} else if constexpr (is_same<_InputIterator, _Sent>::value && __is_segmented_iterator_v<_InputIterator>) {
|
|
using __local_iterator_t = typename __segmented_iterator_traits<_InputIterator>::__local_iterator;
|
|
std::__for_each_segment(__first, __last, [&](__local_iterator_t __lfirst, __local_iterator_t __llast) {
|
|
std::__for_each(__lfirst, __llast, __func, __proj);
|
|
});
|
|
return __last;
|
|
}
|
|
#endif
|
|
for (; __first != __last; ++__first)
|
|
std::__invoke(__func, std::__invoke(__proj, *__first));
|
|
return __first;
|
|
}
|
|
|
|
template <class _InputIterator, class _Func>
|
|
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Func
|
|
for_each(_InputIterator __first, _InputIterator __last, _Func __f) {
|
|
__identity __proj;
|
|
std::__for_each(__first, __last, __f, __proj);
|
|
return __f;
|
|
}
|
|
|
|
_LIBCPP_END_NAMESPACE_STD
|
|
|
|
#endif // _LIBCPP___ALGORITHM_FOR_EACH_H
|