Skip to content

<regex>: Speed up skip optimization for default regex_traits in collate mode #5672

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
Aug 16, 2025
Merged

<regex>: Speed up skip optimization for default regex_traits in collate mode #5672

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
678baa8
`<regex>`: Speed up skip optimization for default `regex_traits` in `…
muellerj2 Aug 9, 2025
45faa27
`is_same_v || is_same_v` => `_Is_any_of_v`
StephanTLavavej Aug 11, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
6 changes: 4 additions & 2 deletions benchmarks/src/regex_search.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -8,13 +8,14 @@
#include "lorem.hpp"

using namespace std;
using namespace regex_constants;

void bm_lorem_search(benchmark::State& state, const char* pattern) {
void bm_lorem_search(benchmark::State& state, const char* pattern, syntax_option_type syntax = ECMAScript) {
string repeated_lorem{lorem_ipsum};
for (long long i = 0; i < state.range(); ++i) {
repeated_lorem += repeated_lorem;
}
regex re{pattern};
regex re{pattern, syntax};

for (auto _ : state) {
benchmark::DoNotOptimize(repeated_lorem);
Expand All @@ -33,6 +34,7 @@ void bm_lorem_search(benchmark::State& state, const char* pattern) {

BENCHMARK_CAPTURE(bm_lorem_search, "^bibe", "^bibe")->Arg(2)->Arg(3)->Arg(4);
BENCHMARK_CAPTURE(bm_lorem_search, "bibe", "bibe")->Arg(2)->Arg(3)->Arg(4);
BENCHMARK_CAPTURE(bm_lorem_search, "bibe".collate, "bibe", regex_constants::collate)->Arg(2)->Arg(3)->Arg(4);
BENCHMARK_CAPTURE(bm_lorem_search, "(bibe)", "(bibe)")->Arg(2)->Arg(3)->Arg(4);
BENCHMARK_CAPTURE(bm_lorem_search, "(bibe)+", "(bibe)+")->Arg(2)->Arg(3)->Arg(4);
BENCHMARK_CAPTURE(bm_lorem_search, "(?:bibe)+", "(?:bibe)+")->Arg(2)->Arg(3)->Arg(4);
Expand Down
6 changes: 6 additions & 0 deletions stl/inc/regex
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3693,6 +3693,8 @@ _BidIt1 _Compare_translate_both(_BidIt1 _Begin1, _BidIt1 _End1, _BidIt2 _Begin2,
// compare character ranges, translating characters in both ranges according to syntax options
if (_Sflags & regex_constants::icase) {
return _STD _Cmp_chrange(_Begin1, _End1, _Begin2, _End2, _Cmp_icase<_RxTraits>{_Traits});
} else if constexpr (_Is_any_of_v<_RxTraits, regex_traits<char>, regex_traits<wchar_t>>) {
return _STD _Cmp_chrange(_Begin1, _End1, _Begin2, _End2, equal_to<typename _RxTraits::char_type>{});
} else if (_Sflags & regex_constants::collate) {
return _STD _Cmp_chrange(_Begin1, _End1, _Begin2, _End2, _Cmp_collate<_RxTraits>{_Traits});
} else {
Expand All @@ -3706,6 +3708,8 @@ _BidIt1 _Compare_translate_left(_BidIt1 _Begin1, _BidIt1 _End1, _BidIt2 _Begin2,
// compare character ranges, translating characters in the left range according to syntax options
if (_Sflags & regex_constants::icase) {
return _STD _Cmp_chrange(_Begin1, _End1, _Begin2, _End2, _Cmp_icase_translateleft<_RxTraits>{_Traits});
} else if constexpr (_Is_any_of_v<_RxTraits, regex_traits<char>, regex_traits<wchar_t>>) {
return _STD _Cmp_chrange(_Begin1, _End1, _Begin2, _End2, equal_to<typename _RxTraits::char_type>{});
} else if (_Sflags & regex_constants::collate) {
return _STD _Cmp_chrange(_Begin1, _End1, _Begin2, _End2, _Cmp_collate_translateleft<_RxTraits>{_Traits});
} else {
Expand All @@ -3720,6 +3724,8 @@ _BidIt1 _Search_translate_left(_BidIt1 _Begin1, _BidIt1 _End1, _BidIt2 _Begin2,
// after translating characters in the left sequence according to syntax options
if (_Sflags & regex_constants::icase) {
return _STD search(_Begin1, _End1, _Begin2, _End2, _Cmp_icase_translateleft<_RxTraits>{_Traits});
} else if constexpr (_Is_any_of_v<_RxTraits, regex_traits<char>, regex_traits<wchar_t>>) {
return _STD search(_Begin1, _End1, _Begin2, _End2, equal_to<typename _RxTraits::char_type>{});
} else if (_Sflags & regex_constants::collate) {
return _STD search(_Begin1, _End1, _Begin2, _End2, _Cmp_collate_translateleft<_RxTraits>{_Traits});
} else {
Expand Down
27 changes: 27 additions & 0 deletions tests/std/tests/VSO_0000000_regex_use/test.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2103,6 +2103,32 @@ void test_gh_5576() {
match_default, "AbGweEXfFlXlLLlffflEXlF");
}

void test_gh_5672() {
// GH-5672: Speed up skip optimization for default `regex_traits` in `collate` mode
// The PR added a faster branch in the skip optimization when matching in collate mode
// for default `regex_traits<char>` and `regex_traits<wchar_t>`.
// The following tests check that searching still works correctly when the faster branch is engaged.
{
test_regex collating_re(&g_regexTester, "g", regex_constants::collate);

collating_re.should_search_match("abcdefghijklmnopqrstuvwxyz", "g");
collating_re.should_search_fail("ABCDEFGHIJKLMNOPQRSTUVWXYZ");
collating_re.should_search_match("zyxwvutsrqponmlkjihgfedcba", "g");
collating_re.should_search_fail("ZYXWVUTSRQPONMLKJIHGFEDCBA");
collating_re.should_search_fail("zyxwvutsrqponmlkjihedcba");
}

{
test_wregex collating_re(&g_regexTester, L"g", regex_constants::collate);

collating_re.should_search_match(L"abcdefghijklmnopqrstuvwxyz", L"g");
collating_re.should_search_fail(L"ABCDEFGHIJKLMNOPQRSTUVWXYZ");
collating_re.should_search_match(L"zyxwvutsrqponmlkjihgfedcba", L"g");
collating_re.should_search_fail(L"ZYXWVUTSRQPONMLKJIHGFEDCBA");
collating_re.should_search_fail(L"zyxwvutsrqponmlkjihedcba");
}
}

int main() {
test_dev10_449367_case_insensitivity_should_work();
test_dev11_462743_regex_collate_should_not_disable_regex_icase();
Expand Down Expand Up @@ -2153,6 +2179,7 @@ int main() {
test_gh_5490();
test_gh_5509();
test_gh_5576();
test_gh_5672();

return g_regexTester.result();
}