[libcxx-commits] [libcxx] [libc++] Optimize the two range overload of mismatch (PR #86853)
Nikolas Klauser via libcxx-commits
libcxx-commits at lists.llvm.org
Mon Apr 1 01:18:05 PDT 2024
https://github.com/philnik777 updated https://github.com/llvm/llvm-project/pull/86853
>From 2c2692348b3bb8ec94c60b0028958643753517cc Mon Sep 17 00:00:00 2001
From: Nikolas Klauser <nikolasklauser at berlin.de>
Date: Tue, 26 Mar 2024 12:27:57 +0100
Subject: [PATCH] [libc++] Optimize the two range overload of mismatch
---
.../benchmarks/algorithms/mismatch.bench.cpp | 16 +++++++++
libcxx/include/__algorithm/mismatch.h | 34 ++++++++++++++++---
libcxx/include/__algorithm/ranges_mismatch.h | 22 +++++++-----
libcxx/include/__algorithm/simd_utils.h | 9 ++++-
.../test/libcxx/transitive_includes/cxx23.csv | 1 +
.../test/libcxx/transitive_includes/cxx26.csv | 1 +
.../mismatch/mismatch.pass.cpp | 8 ++---
7 files changed, 74 insertions(+), 17 deletions(-)
diff --git a/libcxx/benchmarks/algorithms/mismatch.bench.cpp b/libcxx/benchmarks/algorithms/mismatch.bench.cpp
index 06289068bb0492..791782879011e2 100644
--- a/libcxx/benchmarks/algorithms/mismatch.bench.cpp
+++ b/libcxx/benchmarks/algorithms/mismatch.bench.cpp
@@ -37,4 +37,20 @@ BENCHMARK(bm_mismatch<char>)->Apply(BenchmarkSizes);
BENCHMARK(bm_mismatch<short>)->Apply(BenchmarkSizes);
BENCHMARK(bm_mismatch<int>)->Apply(BenchmarkSizes);
+template <class T>
+static void bm_mismatch_two_range_overload(benchmark::State& state) {
+ std::vector<T> vec1(state.range(), '1');
+ std::vector<T> vec2(state.range(), '1');
+ std::mt19937_64 rng(std::random_device{}());
+
+ vec1.back() = '2';
+ for (auto _ : state) {
+ benchmark::DoNotOptimize(vec1);
+ benchmark::DoNotOptimize(std::mismatch(vec1.begin(), vec1.end(), vec2.begin(), vec2.end()));
+ }
+}
+BENCHMARK(bm_mismatch_two_range_overload<char>)->DenseRange(1, 8)->Range(16, 1 << 20);
+BENCHMARK(bm_mismatch_two_range_overload<short>)->DenseRange(1, 8)->Range(16, 1 << 20);
+BENCHMARK(bm_mismatch_two_range_overload<int>)->DenseRange(1, 8)->Range(16, 1 << 20);
+
BENCHMARK_MAIN();
diff --git a/libcxx/include/__algorithm/mismatch.h b/libcxx/include/__algorithm/mismatch.h
index d933a84cada9e9..1962c4ffd1287b 100644
--- a/libcxx/include/__algorithm/mismatch.h
+++ b/libcxx/include/__algorithm/mismatch.h
@@ -11,6 +11,7 @@
#define _LIBCPP___ALGORITHM_MISMATCH_H
#include <__algorithm/comp.h>
+#include <__algorithm/min.h>
#include <__algorithm/simd_utils.h>
#include <__algorithm/unwrap_iter.h>
#include <__config>
@@ -134,6 +135,25 @@ mismatch(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __fi
}
#if _LIBCPP_STD_VER >= 14
+template <class _Iter1, class _Sent1, class _Iter2, class _Sent2, class _Pred, class _Proj1, class _Proj2>
+[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_Iter1, _Iter2> __mismatch(
+ _Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2, _Pred& __pred, _Proj1& __proj1, _Proj2& __proj2) {
+ while (__first1 != __last1 && __first2 != __last2) {
+ if (!std::__invoke(__pred, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))
+ break;
+ ++__first1;
+ ++__first2;
+ }
+ return {std::move(__first1), std::move(__first2)};
+}
+
+template <class _Tp, class _Pred, class _Proj1, class _Proj2>
+[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_Tp*, _Tp*>
+__mismatch(_Tp* __first1, _Tp* __last1, _Tp* __first2, _Tp* __last2, _Pred& __pred, _Proj1& __proj1, _Proj2& __proj2) {
+ auto __len = std::min(__last1 - __first1, __last2 - __first2);
+ return std::__mismatch(__first1, __first1 + __len, __first2, __pred, __proj1, __proj2);
+}
+
template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_InputIterator1, _InputIterator2>
mismatch(_InputIterator1 __first1,
@@ -141,10 +161,16 @@ mismatch(_InputIterator1 __first1,
_InputIterator2 __first2,
_InputIterator2 __last2,
_BinaryPredicate __pred) {
- for (; __first1 != __last1 && __first2 != __last2; ++__first1, (void)++__first2)
- if (!__pred(*__first1, *__first2))
- break;
- return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
+ __identity __proj;
+ auto __res = std::__mismatch(
+ std::__unwrap_iter(__first1),
+ std::__unwrap_iter(__last1),
+ std::__unwrap_iter(__first2),
+ std::__unwrap_iter(__last2),
+ __pred,
+ __proj,
+ __proj);
+ return {std::__rewrap_iter(__first1, __res.first), std::__rewrap_iter(__first2, __res.second)};
}
template <class _InputIterator1, class _InputIterator2>
diff --git a/libcxx/include/__algorithm/ranges_mismatch.h b/libcxx/include/__algorithm/ranges_mismatch.h
index 037af39126230a..d8a7dd43af09d5 100644
--- a/libcxx/include/__algorithm/ranges_mismatch.h
+++ b/libcxx/include/__algorithm/ranges_mismatch.h
@@ -10,6 +10,8 @@
#define _LIBCPP___ALGORITHM_RANGES_MISMATCH_H
#include <__algorithm/in_in_result.h>
+#include <__algorithm/mismatch.h>
+#include <__algorithm/unwrap_range.h>
#include <__config>
#include <__functional/identity.h>
#include <__functional/invoke.h>
@@ -42,13 +44,17 @@ struct __fn {
template <class _I1, class _S1, class _I2, class _S2, class _Pred, class _Proj1, class _Proj2>
static _LIBCPP_HIDE_FROM_ABI constexpr mismatch_result<_I1, _I2>
__go(_I1 __first1, _S1 __last1, _I2 __first2, _S2 __last2, _Pred& __pred, _Proj1& __proj1, _Proj2& __proj2) {
- while (__first1 != __last1 && __first2 != __last2) {
- if (!std::invoke(__pred, std::invoke(__proj1, *__first1), std::invoke(__proj2, *__first2)))
- break;
- ++__first1;
- ++__first2;
+ if constexpr (forward_iterator<_I1> && forward_iterator<_I2>) {
+ auto __range1 = std::__unwrap_range(__first1, __last1);
+ auto __range2 = std::__unwrap_range(__first2, __last2);
+ auto __res =
+ std::__mismatch(__range1.first, __range1.second, __range2.first, __range2.second, __pred, __proj1, __proj2);
+ return {std::__rewrap_range<_S1>(__first1, __res.first), std::__rewrap_range<_S2>(__first2, __res.second)};
+ } else {
+ auto __res = std::__mismatch(
+ std::move(__first1), std::move(__last1), std::move(__first2), std::move(__last2), __pred, __proj1, __proj2);
+ return {std::move(__res.first), std::move(__res.second)};
}
- return {std::move(__first1), std::move(__first2)};
}
template <input_iterator _I1,
@@ -71,8 +77,8 @@ struct __fn {
class _Proj1 = identity,
class _Proj2 = identity>
requires indirectly_comparable<iterator_t<_R1>, iterator_t<_R2>, _Pred, _Proj1, _Proj2>
- _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr mismatch_result<borrowed_iterator_t<_R1>,
- borrowed_iterator_t<_R2>>
+ _LIBCPP_NODISCARD_EXT
+ _LIBCPP_HIDE_FROM_ABI constexpr mismatch_result<borrowed_iterator_t<_R1>, borrowed_iterator_t<_R2>>
operator()(_R1&& __r1, _R2&& __r2, _Pred __pred = {}, _Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const {
return __go(
ranges::begin(__r1), ranges::end(__r1), ranges::begin(__r2), ranges::end(__r2), __pred, __proj1, __proj2);
diff --git a/libcxx/include/__algorithm/simd_utils.h b/libcxx/include/__algorithm/simd_utils.h
index 1aedb3db010f77..989a1957987e1e 100644
--- a/libcxx/include/__algorithm/simd_utils.h
+++ b/libcxx/include/__algorithm/simd_utils.h
@@ -9,6 +9,7 @@
#ifndef _LIBCPP___ALGORITHM_SIMD_UTILS_H
#define _LIBCPP___ALGORITHM_SIMD_UTILS_H
+#include <__algorithm/min.h>
#include <__bit/bit_cast.h>
#include <__bit/countr.h>
#include <__config>
@@ -22,6 +23,9 @@
# pragma GCC system_header
#endif
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
// TODO: Find out how altivec changes things and allow vectorizations there too.
#if _LIBCPP_STD_VER >= 14 && defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER >= 1700 && !defined(__ALTIVEC__)
# define _LIBCPP_HAS_ALGORITHM_VECTOR_UTILS 1
@@ -94,7 +98,8 @@ _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI size_t __find_first_set(__simd_vector<_T
// This has MSan disabled du to https://github.com/llvm/llvm-project/issues/85876
auto __impl = [&]<class _MaskT>(_MaskT) _LIBCPP_NO_SANITIZE("memory") noexcept {
- return std::__countr_zero(__builtin_bit_cast(_MaskT, __builtin_convertvector(__vec, __mask_vec)));
+ return std::min<size_t>(
+ _Np, std::__countr_zero(__builtin_bit_cast(_MaskT, __builtin_convertvector(__vec, __mask_vec))));
};
if constexpr (sizeof(__mask_vec) == sizeof(uint8_t)) {
@@ -120,4 +125,6 @@ _LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP_HAS_ALGORITHM_VECTOR_UTILS
+_LIBCPP_POP_MACROS
+
#endif // _LIBCPP___ALGORITHM_SIMD_UTILS_H
diff --git a/libcxx/test/libcxx/transitive_includes/cxx23.csv b/libcxx/test/libcxx/transitive_includes/cxx23.csv
index 79c67dc00cfb9b..69429b5bce8250 100644
--- a/libcxx/test/libcxx/transitive_includes/cxx23.csv
+++ b/libcxx/test/libcxx/transitive_includes/cxx23.csv
@@ -452,6 +452,7 @@ random vector
random version
ranges compare
ranges cstddef
+ranges cstdint
ranges cwchar
ranges initializer_list
ranges iterator
diff --git a/libcxx/test/libcxx/transitive_includes/cxx26.csv b/libcxx/test/libcxx/transitive_includes/cxx26.csv
index 79c67dc00cfb9b..69429b5bce8250 100644
--- a/libcxx/test/libcxx/transitive_includes/cxx26.csv
+++ b/libcxx/test/libcxx/transitive_includes/cxx26.csv
@@ -452,6 +452,7 @@ random vector
random version
ranges compare
ranges cstddef
+ranges cstdint
ranges cwchar
ranges initializer_list
ranges iterator
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/mismatch/mismatch.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/mismatch/mismatch.pass.cpp
index 55c9eea863c3ff..eb5f7cacdde34b 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/mismatch/mismatch.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/mismatch/mismatch.pass.cpp
@@ -187,8 +187,8 @@ int main(int, char**) {
{ // check the tail of the vectorized loop
for (size_t vec_size = 1; vec_size != 256; ++vec_size) {
{
- std::vector<char> lhs(256);
- std::vector<char> rhs(256);
+ std::vector<char> lhs(vec_size);
+ std::vector<char> rhs(vec_size);
check<char*>(lhs, rhs, lhs.size());
lhs.back() = 1;
@@ -199,8 +199,8 @@ int main(int, char**) {
rhs.back() = 0;
}
{
- std::vector<int> lhs(256);
- std::vector<int> rhs(256);
+ std::vector<int> lhs(vec_size);
+ std::vector<int> rhs(vec_size);
check<int*>(lhs, rhs, lhs.size());
lhs.back() = 1;
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