[libcxx-commits] [libcxx] a12744f - [libc++] Optimize ranges::swap_ranges for vector<bool>::iterator (#121150)
via libcxx-commits
libcxx-commits at lists.llvm.org
Tue Mar 4 14:15:41 PST 2025
Author: Peng Liu
Date: 2025-03-04T17:15:36-05:00
New Revision: a12744ff05bbc2d0de711afb8b3a1c7a03a33914
URL: https://github.com/llvm/llvm-project/commit/a12744ff05bbc2d0de711afb8b3a1c7a03a33914
DIFF: https://github.com/llvm/llvm-project/commit/a12744ff05bbc2d0de711afb8b3a1c7a03a33914.diff
LOG: [libc++] Optimize ranges::swap_ranges for vector<bool>::iterator (#121150)
This PR optimizes the performance of `std::ranges::swap_ranges` for
`vector<bool>::iterator`, addressing a subtask outlined in issue #64038.
The optimizations yield performance improvements of up to **611x** for
aligned range swap and **78x** for unaligned range swap comparison.
Additionally, comprehensive tests covering up to 4 storage words (256
bytes) with odd and even bit sizes are provided, which validate the
proposed optimizations in this patch.
Added:
libcxx/test/benchmarks/algorithms/swap_ranges.bench.cpp
Modified:
libcxx/docs/ReleaseNotes/21.rst
libcxx/include/__algorithm/swap_ranges.h
libcxx/include/__bit_reference
libcxx/test/std/algorithms/alg.modifying.operations/alg.swap/ranges.swap_ranges.pass.cpp
libcxx/test/std/algorithms/alg.modifying.operations/alg.swap/swap_ranges.pass.cpp
Removed:
################################################################################
diff --git a/libcxx/docs/ReleaseNotes/21.rst b/libcxx/docs/ReleaseNotes/21.rst
index e7cfa625a132c..f45a448e52cc0 100644
--- a/libcxx/docs/ReleaseNotes/21.rst
+++ b/libcxx/docs/ReleaseNotes/21.rst
@@ -50,6 +50,9 @@ Improvements and New Features
- The ``std::ranges::equal`` algorithm has been optimized for ``std::vector<bool>::iterator``, resulting in a performance
improvement of up to 188x.
+- The ``std::ranges::swap_ranges`` algorithm has been optimized for ``std::vector<bool>::iterator``, resulting in a
+ performance improvement of up to 611x.
+
- Updated formatting library to Unicode 16.0.0.
Deprecations and Removals
diff --git a/libcxx/include/__algorithm/swap_ranges.h b/libcxx/include/__algorithm/swap_ranges.h
index 54b453b72360e..2731d4feaa63d 100644
--- a/libcxx/include/__algorithm/swap_ranges.h
+++ b/libcxx/include/__algorithm/swap_ranges.h
@@ -10,9 +10,12 @@
#define _LIBCPP___ALGORITHM_SWAP_RANGES_H
#include <__algorithm/iterator_operations.h>
+#include <__algorithm/min.h>
#include <__config>
+#include <__fwd/bit_reference.h>
#include <__utility/move.h>
#include <__utility/pair.h>
+#include <__utility/swap.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
@@ -23,6 +26,165 @@ _LIBCPP_PUSH_MACROS
_LIBCPP_BEGIN_NAMESPACE_STD
+template <class _Cl, class _Cr>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __bit_iterator<_Cr, false> __swap_ranges_aligned(
+ __bit_iterator<_Cl, false> __first, __bit_iterator<_Cl, false> __last, __bit_iterator<_Cr, false> __result) {
+ using _I1 = __bit_iterator<_Cl, false>;
+ using
diff erence_type = typename _I1::
diff erence_type;
+ using __storage_type = typename _I1::__storage_type;
+
+ const int __bits_per_word = _I1::__bits_per_word;
+
diff erence_type __n = __last - __first;
+ if (__n > 0) {
+ // do first word
+ if (__first.__ctz_ != 0) {
+ unsigned __clz = __bits_per_word - __first.__ctz_;
+
diff erence_type __dn = std::min(static_cast<
diff erence_type>(__clz), __n);
+ __n -= __dn;
+ __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz - __dn));
+ __storage_type __b1 = *__first.__seg_ & __m;
+ *__first.__seg_ &= ~__m;
+ __storage_type __b2 = *__result.__seg_ & __m;
+ *__result.__seg_ &= ~__m;
+ *__result.__seg_ |= __b1;
+ *__first.__seg_ |= __b2;
+ __result.__seg_ += (__dn + __result.__ctz_) / __bits_per_word;
+ __result.__ctz_ = static_cast<unsigned>((__dn + __result.__ctz_) % __bits_per_word);
+ ++__first.__seg_;
+ // __first.__ctz_ = 0;
+ }
+ // __first.__ctz_ == 0;
+ // do middle words
+ for (; __n >= __bits_per_word; __n -= __bits_per_word, ++__first.__seg_, ++__result.__seg_)
+ swap(*__first.__seg_, *__result.__seg_);
+ // do last word
+ if (__n > 0) {
+ __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
+ __storage_type __b1 = *__first.__seg_ & __m;
+ *__first.__seg_ &= ~__m;
+ __storage_type __b2 = *__result.__seg_ & __m;
+ *__result.__seg_ &= ~__m;
+ *__result.__seg_ |= __b1;
+ *__first.__seg_ |= __b2;
+ __result.__ctz_ = static_cast<unsigned>(__n);
+ }
+ }
+ return __result;
+}
+
+template <class _Cl, class _Cr>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __bit_iterator<_Cr, false> __swap_ranges_unaligned(
+ __bit_iterator<_Cl, false> __first, __bit_iterator<_Cl, false> __last, __bit_iterator<_Cr, false> __result) {
+ using _I1 = __bit_iterator<_Cl, false>;
+ using
diff erence_type = typename _I1::
diff erence_type;
+ using __storage_type = typename _I1::__storage_type;
+
+ const int __bits_per_word = _I1::__bits_per_word;
+
diff erence_type __n = __last - __first;
+ if (__n > 0) {
+ // do first word
+ if (__first.__ctz_ != 0) {
+ unsigned __clz_f = __bits_per_word - __first.__ctz_;
+
diff erence_type __dn = std::min(static_cast<
diff erence_type>(__clz_f), __n);
+ __n -= __dn;
+ __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
+ __storage_type __b1 = *__first.__seg_ & __m;
+ *__first.__seg_ &= ~__m;
+ unsigned __clz_r = __bits_per_word - __result.__ctz_;
+ __storage_type __ddn = std::min<__storage_type>(__dn, __clz_r);
+ __m = (~__storage_type(0) << __result.__ctz_) & (~__storage_type(0) >> (__clz_r - __ddn));
+ __storage_type __b2 = *__result.__seg_ & __m;
+ *__result.__seg_ &= ~__m;
+ if (__result.__ctz_ > __first.__ctz_) {
+ unsigned __s = __result.__ctz_ - __first.__ctz_;
+ *__result.__seg_ |= __b1 << __s;
+ *__first.__seg_ |= __b2 >> __s;
+ } else {
+ unsigned __s = __first.__ctz_ - __result.__ctz_;
+ *__result.__seg_ |= __b1 >> __s;
+ *__first.__seg_ |= __b2 << __s;
+ }
+ __result.__seg_ += (__ddn + __result.__ctz_) / __bits_per_word;
+ __result.__ctz_ = static_cast<unsigned>((__ddn + __result.__ctz_) % __bits_per_word);
+ __dn -= __ddn;
+ if (__dn > 0) {
+ __m = ~__storage_type(0) >> (__bits_per_word - __dn);
+ __b2 = *__result.__seg_ & __m;
+ *__result.__seg_ &= ~__m;
+ unsigned __s = __first.__ctz_ + __ddn;
+ *__result.__seg_ |= __b1 >> __s;
+ *__first.__seg_ |= __b2 << __s;
+ __result.__ctz_ = static_cast<unsigned>(__dn);
+ }
+ ++__first.__seg_;
+ // __first.__ctz_ = 0;
+ }
+ // __first.__ctz_ == 0;
+ // do middle words
+ __storage_type __m = ~__storage_type(0) << __result.__ctz_;
+ unsigned __clz_r = __bits_per_word - __result.__ctz_;
+ for (; __n >= __bits_per_word; __n -= __bits_per_word, ++__first.__seg_) {
+ __storage_type __b1 = *__first.__seg_;
+ __storage_type __b2 = *__result.__seg_ & __m;
+ *__result.__seg_ &= ~__m;
+ *__result.__seg_ |= __b1 << __result.__ctz_;
+ *__first.__seg_ = __b2 >> __result.__ctz_;
+ ++__result.__seg_;
+ __b2 = *__result.__seg_ & ~__m;
+ *__result.__seg_ &= __m;
+ *__result.__seg_ |= __b1 >> __clz_r;
+ *__first.__seg_ |= __b2 << __clz_r;
+ }
+ // do last word
+ if (__n > 0) {
+ __m = ~__storage_type(0) >> (__bits_per_word - __n);
+ __storage_type __b1 = *__first.__seg_ & __m;
+ *__first.__seg_ &= ~__m;
+ __storage_type __dn = std::min<__storage_type>(__n, __clz_r);
+ __m = (~__storage_type(0) << __result.__ctz_) & (~__storage_type(0) >> (__clz_r - __dn));
+ __storage_type __b2 = *__result.__seg_ & __m;
+ *__result.__seg_ &= ~__m;
+ *__result.__seg_ |= __b1 << __result.__ctz_;
+ *__first.__seg_ |= __b2 >> __result.__ctz_;
+ __result.__seg_ += (__dn + __result.__ctz_) / __bits_per_word;
+ __result.__ctz_ = static_cast<unsigned>((__dn + __result.__ctz_) % __bits_per_word);
+ __n -= __dn;
+ if (__n > 0) {
+ __m = ~__storage_type(0) >> (__bits_per_word - __n);
+ __b2 = *__result.__seg_ & __m;
+ *__result.__seg_ &= ~__m;
+ *__result.__seg_ |= __b1 >> __dn;
+ *__first.__seg_ |= __b2 << __dn;
+ __result.__ctz_ = static_cast<unsigned>(__n);
+ }
+ }
+ }
+ return __result;
+}
+
+// 2+1 iterators: size2 >= size1; used by std::swap_ranges.
+template <class, class _Cl, class _Cr>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<__bit_iterator<_Cl, false>, __bit_iterator<_Cr, false> >
+__swap_ranges(__bit_iterator<_Cl, false> __first1,
+ __bit_iterator<_Cl, false> __last1,
+ __bit_iterator<_Cr, false> __first2) {
+ if (__first1.__ctz_ == __first2.__ctz_)
+ return std::make_pair(__last1, std::__swap_ranges_aligned(__first1, __last1, __first2));
+ return std::make_pair(__last1, std::__swap_ranges_unaligned(__first1, __last1, __first2));
+}
+
+// 2+2 iterators: used by std::ranges::swap_ranges.
+template <class _AlgPolicy, class _Cl, class _Cr>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<__bit_iterator<_Cl, false>, __bit_iterator<_Cr, false> >
+__swap_ranges(__bit_iterator<_Cl, false> __first1,
+ __bit_iterator<_Cl, false> __last1,
+ __bit_iterator<_Cr, false> __first2,
+ __bit_iterator<_Cr, false> __last2) {
+ if (__last1 - __first1 < __last2 - __first2)
+ return std::make_pair(__last1, std::__swap_ranges<_AlgPolicy>(__first1, __last1, __first2).second);
+ return std::make_pair(std::__swap_ranges<_AlgPolicy>(__first2, __last2, __first1).second, __last2);
+}
+
// 2+2 iterators: the shorter size will be used.
template <class _AlgPolicy, class _ForwardIterator1, class _Sentinel1, class _ForwardIterator2, class _Sentinel2>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_ForwardIterator1, _ForwardIterator2>
diff --git a/libcxx/include/__bit_reference b/libcxx/include/__bit_reference
index 079d1de9dd523..f91250c4a440d 100644
--- a/libcxx/include/__bit_reference
+++ b/libcxx/include/__bit_reference
@@ -16,6 +16,7 @@
#include <__algorithm/copy_n.h>
#include <__algorithm/equal.h>
#include <__algorithm/min.h>
+#include <__algorithm/swap_ranges.h>
#include <__assert>
#include <__bit/countr.h>
#include <__compare/ordering.h>
@@ -215,152 +216,6 @@ private:
__mask_(__m) {}
};
-// swap_ranges
-
-template <class _Cl, class _Cr>
-_LIBCPP_HIDE_FROM_ABI __bit_iterator<_Cr, false> __swap_ranges_aligned(
- __bit_iterator<_Cl, false> __first, __bit_iterator<_Cl, false> __last, __bit_iterator<_Cr, false> __result) {
- using _I1 = __bit_iterator<_Cl, false>;
- using
diff erence_type = typename _I1::
diff erence_type;
- using __storage_type = typename _I1::__storage_type;
-
- const int __bits_per_word = _I1::__bits_per_word;
-
diff erence_type __n = __last - __first;
- if (__n > 0) {
- // do first word
- if (__first.__ctz_ != 0) {
- unsigned __clz = __bits_per_word - __first.__ctz_;
-
diff erence_type __dn = std::min(static_cast<
diff erence_type>(__clz), __n);
- __n -= __dn;
- __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz - __dn));
- __storage_type __b1 = *__first.__seg_ & __m;
- *__first.__seg_ &= ~__m;
- __storage_type __b2 = *__result.__seg_ & __m;
- *__result.__seg_ &= ~__m;
- *__result.__seg_ |= __b1;
- *__first.__seg_ |= __b2;
- __result.__seg_ += (__dn + __result.__ctz_) / __bits_per_word;
- __result.__ctz_ = static_cast<unsigned>((__dn + __result.__ctz_) % __bits_per_word);
- ++__first.__seg_;
- // __first.__ctz_ = 0;
- }
- // __first.__ctz_ == 0;
- // do middle words
- for (; __n >= __bits_per_word; __n -= __bits_per_word, ++__first.__seg_, ++__result.__seg_)
- swap(*__first.__seg_, *__result.__seg_);
- // do last word
- if (__n > 0) {
- __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
- __storage_type __b1 = *__first.__seg_ & __m;
- *__first.__seg_ &= ~__m;
- __storage_type __b2 = *__result.__seg_ & __m;
- *__result.__seg_ &= ~__m;
- *__result.__seg_ |= __b1;
- *__first.__seg_ |= __b2;
- __result.__ctz_ = static_cast<unsigned>(__n);
- }
- }
- return __result;
-}
-
-template <class _Cl, class _Cr>
-_LIBCPP_HIDE_FROM_ABI __bit_iterator<_Cr, false> __swap_ranges_unaligned(
- __bit_iterator<_Cl, false> __first, __bit_iterator<_Cl, false> __last, __bit_iterator<_Cr, false> __result) {
- using _I1 = __bit_iterator<_Cl, false>;
- using
diff erence_type = typename _I1::
diff erence_type;
- using __storage_type = typename _I1::__storage_type;
-
- const int __bits_per_word = _I1::__bits_per_word;
-
diff erence_type __n = __last - __first;
- if (__n > 0) {
- // do first word
- if (__first.__ctz_ != 0) {
- unsigned __clz_f = __bits_per_word - __first.__ctz_;
-
diff erence_type __dn = std::min(static_cast<
diff erence_type>(__clz_f), __n);
- __n -= __dn;
- __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
- __storage_type __b1 = *__first.__seg_ & __m;
- *__first.__seg_ &= ~__m;
- unsigned __clz_r = __bits_per_word - __result.__ctz_;
- __storage_type __ddn = std::min<__storage_type>(__dn, __clz_r);
- __m = (~__storage_type(0) << __result.__ctz_) & (~__storage_type(0) >> (__clz_r - __ddn));
- __storage_type __b2 = *__result.__seg_ & __m;
- *__result.__seg_ &= ~__m;
- if (__result.__ctz_ > __first.__ctz_) {
- unsigned __s = __result.__ctz_ - __first.__ctz_;
- *__result.__seg_ |= __b1 << __s;
- *__first.__seg_ |= __b2 >> __s;
- } else {
- unsigned __s = __first.__ctz_ - __result.__ctz_;
- *__result.__seg_ |= __b1 >> __s;
- *__first.__seg_ |= __b2 << __s;
- }
- __result.__seg_ += (__ddn + __result.__ctz_) / __bits_per_word;
- __result.__ctz_ = static_cast<unsigned>((__ddn + __result.__ctz_) % __bits_per_word);
- __dn -= __ddn;
- if (__dn > 0) {
- __m = ~__storage_type(0) >> (__bits_per_word - __dn);
- __b2 = *__result.__seg_ & __m;
- *__result.__seg_ &= ~__m;
- unsigned __s = __first.__ctz_ + __ddn;
- *__result.__seg_ |= __b1 >> __s;
- *__first.__seg_ |= __b2 << __s;
- __result.__ctz_ = static_cast<unsigned>(__dn);
- }
- ++__first.__seg_;
- // __first.__ctz_ = 0;
- }
- // __first.__ctz_ == 0;
- // do middle words
- __storage_type __m = ~__storage_type(0) << __result.__ctz_;
- unsigned __clz_r = __bits_per_word - __result.__ctz_;
- for (; __n >= __bits_per_word; __n -= __bits_per_word, ++__first.__seg_) {
- __storage_type __b1 = *__first.__seg_;
- __storage_type __b2 = *__result.__seg_ & __m;
- *__result.__seg_ &= ~__m;
- *__result.__seg_ |= __b1 << __result.__ctz_;
- *__first.__seg_ = __b2 >> __result.__ctz_;
- ++__result.__seg_;
- __b2 = *__result.__seg_ & ~__m;
- *__result.__seg_ &= __m;
- *__result.__seg_ |= __b1 >> __clz_r;
- *__first.__seg_ |= __b2 << __clz_r;
- }
- // do last word
- if (__n > 0) {
- __m = ~__storage_type(0) >> (__bits_per_word - __n);
- __storage_type __b1 = *__first.__seg_ & __m;
- *__first.__seg_ &= ~__m;
- __storage_type __dn = std::min<__storage_type>(__n, __clz_r);
- __m = (~__storage_type(0) << __result.__ctz_) & (~__storage_type(0) >> (__clz_r - __dn));
- __storage_type __b2 = *__result.__seg_ & __m;
- *__result.__seg_ &= ~__m;
- *__result.__seg_ |= __b1 << __result.__ctz_;
- *__first.__seg_ |= __b2 >> __result.__ctz_;
- __result.__seg_ += (__dn + __result.__ctz_) / __bits_per_word;
- __result.__ctz_ = static_cast<unsigned>((__dn + __result.__ctz_) % __bits_per_word);
- __n -= __dn;
- if (__n > 0) {
- __m = ~__storage_type(0) >> (__bits_per_word - __n);
- __b2 = *__result.__seg_ & __m;
- *__result.__seg_ &= ~__m;
- *__result.__seg_ |= __b1 >> __dn;
- *__first.__seg_ |= __b2 << __dn;
- __result.__ctz_ = static_cast<unsigned>(__n);
- }
- }
- }
- return __result;
-}
-
-template <class _Cl, class _Cr>
-inline _LIBCPP_HIDE_FROM_ABI __bit_iterator<_Cr, false> swap_ranges(
- __bit_iterator<_Cl, false> __first1, __bit_iterator<_Cl, false> __last1, __bit_iterator<_Cr, false> __first2) {
- if (__first1.__ctz_ == __first2.__ctz_)
- return std::__swap_ranges_aligned(__first1, __last1, __first2);
- return std::__swap_ranges_unaligned(__first1, __last1, __first2);
-}
-
// rotate
template <class _Cp>
@@ -644,14 +499,14 @@ private:
template <class _AlgPolicy>
friend struct __copy_backward_impl;
template <class _Cl, class _Cr>
- friend __bit_iterator<_Cr, false>
+ _LIBCPP_CONSTEXPR_SINCE_CXX20 friend __bit_iterator<_Cr, false>
__swap_ranges_aligned(__bit_iterator<_Cl, false>, __bit_iterator<_Cl, false>, __bit_iterator<_Cr, false>);
template <class _Cl, class _Cr>
- friend __bit_iterator<_Cr, false>
+ _LIBCPP_CONSTEXPR_SINCE_CXX20 friend __bit_iterator<_Cr, false>
__swap_ranges_unaligned(__bit_iterator<_Cl, false>, __bit_iterator<_Cl, false>, __bit_iterator<_Cr, false>);
- template <class _Cl, class _Cr>
- friend __bit_iterator<_Cr, false>
- swap_ranges(__bit_iterator<_Cl, false>, __bit_iterator<_Cl, false>, __bit_iterator<_Cr, false>);
+ template <class, class _Cl, class _Cr>
+ _LIBCPP_CONSTEXPR_SINCE_CXX20 friend pair<__bit_iterator<_Cl, false>, __bit_iterator<_Cr, false> >
+ __swap_ranges(__bit_iterator<_Cl, false>, __bit_iterator<_Cl, false>, __bit_iterator<_Cr, false>);
template <class _Dp>
_LIBCPP_CONSTEXPR_SINCE_CXX20 friend __bit_iterator<_Dp, false>
rotate(__bit_iterator<_Dp, false>, __bit_iterator<_Dp, false>, __bit_iterator<_Dp, false>);
diff --git a/libcxx/test/benchmarks/algorithms/swap_ranges.bench.cpp b/libcxx/test/benchmarks/algorithms/swap_ranges.bench.cpp
new file mode 100644
index 0000000000000..0c6dc10a6b7d6
--- /dev/null
+++ b/libcxx/test/benchmarks/algorithms/swap_ranges.bench.cpp
@@ -0,0 +1,66 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+#include <algorithm>
+#include <benchmark/benchmark.h>
+#include <vector>
+
+static void bm_ranges_swap_ranges_vb_aligned(benchmark::State& state) {
+ auto n = state.range();
+ std::vector<bool> vec1(n, true);
+ std::vector<bool> vec2(n, false);
+ for (auto _ : state) {
+ benchmark::DoNotOptimize(std::ranges::swap_ranges(vec1, vec2));
+ benchmark::DoNotOptimize(&vec1);
+ benchmark::DoNotOptimize(&vec2);
+ }
+}
+
+static void bm_ranges_swap_ranges_vb_unaligned(benchmark::State& state) {
+ auto n = state.range();
+ std::vector<bool> vec1(n, true);
+ std::vector<bool> vec2(n + 8, true);
+ auto beg1 = std::ranges::begin(vec1);
+ auto end1 = std::ranges::end(vec1);
+ auto beg2 = std::ranges::begin(vec2) + 4;
+ auto end2 = std::ranges::end(vec2) - 4;
+ for (auto _ : state) {
+ benchmark::DoNotOptimize(std::ranges::swap_ranges(beg1, end1, beg2, end2));
+ benchmark::DoNotOptimize(&vec1);
+ benchmark::DoNotOptimize(&vec2);
+ }
+}
+
+// Test std::ranges::swap_ranges for vector<bool>::iterator
+BENCHMARK(bm_ranges_swap_ranges_vb_aligned)->RangeMultiplier(2)->Range(8, 1 << 20);
+BENCHMARK(bm_ranges_swap_ranges_vb_unaligned)->Range(8, 1 << 20);
+
+static void bm_swap_ranges_vb(benchmark::State& state, bool aligned) {
+ auto n = state.range();
+ std::vector<bool> vec1(n, true);
+ std::vector<bool> vec2(aligned ? n : n + 8, true);
+ auto beg1 = vec1.begin();
+ auto end1 = vec1.end();
+ auto beg2 = aligned ? vec2.begin() : vec2.begin() + 4;
+ for (auto _ : state) {
+ benchmark::DoNotOptimize(std::swap_ranges(beg1, end1, beg2));
+ benchmark::DoNotOptimize(&vec1);
+ benchmark::DoNotOptimize(&vec2);
+ }
+}
+
+static void bm_swap_ranges_vb_aligned(benchmark::State& state) { bm_swap_ranges_vb(state, true); }
+static void bm_swap_ranges_vb_unaligned(benchmark::State& state) { bm_swap_ranges_vb(state, false); }
+
+// Test std::swap_ranges for vector<bool>::iterator
+BENCHMARK(bm_swap_ranges_vb_aligned)->Range(8, 1 << 20);
+BENCHMARK(bm_swap_ranges_vb_unaligned)->Range(8, 1 << 20);
+
+BENCHMARK_MAIN();
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.swap/ranges.swap_ranges.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.swap/ranges.swap_ranges.pass.cpp
index 9b61768cffd97..93090ed6138f8 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.swap/ranges.swap_ranges.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.swap/ranges.swap_ranges.pass.cpp
@@ -23,6 +23,7 @@
#include <array>
#include <cassert>
#include <ranges>
+#include <vector>
#include <cstdio>
@@ -134,6 +135,22 @@ constexpr void test_rval_range() {
}
}
+template <std::size_t N>
+constexpr void test_vector_bool() {
+ { // Test swap_ranges() with aligned bytes
+ std::vector<bool> f(N, false), t(N, true);
+ std::ranges::swap_ranges(f, t);
+ assert(std::all_of(f.begin(), f.end(), [](bool b) { return b; }));
+ assert(std::all_of(t.begin(), t.end(), [](bool b) { return !b; }));
+ }
+ { // Test swap_ranges() with unaligned bytes
+ std::vector<bool> f(N, false), t(N + 8, true);
+ std::ranges::swap_ranges(f.begin(), f.end(), t.begin() + 4, t.end() - 4);
+ assert(std::all_of(f.begin(), f.end(), [](bool b) { return b; }));
+ assert(std::all_of(t.begin() + 4, t.end() - 4, [](bool b) { return !b; }));
+ }
+}
+
constexpr bool test() {
test_range();
test_sentinel();
@@ -148,6 +165,15 @@ constexpr bool test() {
});
});
+ { // Test vector<bool>::iterator optimization
+ test_vector_bool<8>();
+ test_vector_bool<19>();
+ test_vector_bool<32>();
+ test_vector_bool<49>();
+ test_vector_bool<64>();
+ test_vector_bool<199>();
+ test_vector_bool<256>();
+ }
return true;
}
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.swap/swap_ranges.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.swap/swap_ranges.pass.cpp
index 810aa93e076ee..889794dff9fab 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.swap/swap_ranges.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.swap/swap_ranges.pass.cpp
@@ -19,6 +19,7 @@
#include <memory>
#include <type_traits>
#include <utility>
+#include <vector>
#include "test_macros.h"
#include "test_iterators.h"
@@ -110,6 +111,23 @@ TEST_CONSTEXPR_CXX20 bool test_simple_cases() {
return true;
}
+template <std::size_t N>
+TEST_CONSTEXPR_CXX20 void test_vector_bool() {
+ std::vector<bool> f(N, false), t(N, true);
+ { // Test swap_ranges() with aligned bytes
+ std::vector<bool> f1 = f, t1 = t;
+ std::swap_ranges(f1.begin(), f1.end(), t1.begin());
+ assert(f1 == t);
+ assert(t1 == f);
+ }
+ { // Test swap_ranges() with unaligned bytes
+ std::vector<bool> f1(N, false), t1(N + 8, true);
+ std::swap_ranges(f1.begin(), f1.end(), t1.begin() + 4);
+ assert(std::equal(f1.begin(), f1.end(), t.begin()));
+ assert(std::equal(t1.begin() + 4, t1.end() - 4, f.begin()));
+ }
+}
+
TEST_CONSTEXPR_CXX20 bool test() {
test_simple_cases<forward_iterator, forward_iterator>();
test_simple_cases<forward_iterator, bidirectional_iterator>();
@@ -130,6 +148,16 @@ TEST_CONSTEXPR_CXX20 bool test() {
types::for_each(types::forward_iterator_list<std::unique_ptr<int>*>(), TestUniquePtr());
#endif
+ { // Test vector<bool>::iterator optimization
+ test_vector_bool<8>();
+ test_vector_bool<19>();
+ test_vector_bool<32>();
+ test_vector_bool<49>();
+ test_vector_bool<64>();
+ test_vector_bool<199>();
+ test_vector_bool<256>();
+ }
+
return true;
}
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