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Merged
merged 12 commits into from
Oct 4, 2025
Merged

Add some coverage of constexpr vector<bool> #5728

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e68ab23
Add some coverage of constexpr `vector<bool>`
AlexGuteniev Sep 17, 2025
412f03b
preprocessor comments
AlexGuteniev Sep 18, 2025
2c5a892
ICE? What ICE?
AlexGuteniev Sep 18, 2025
80d191f
Merge remote-tracking branch 'upstream/main' into compile-time-boo
AlexGuteniev Sep 22, 2025
ce7a6de
Mark the bug to work around
AlexGuteniev Sep 22, 2025
e0f3340
shorter
AlexGuteniev Sep 22, 2025
b10a2e1
Merge branch 'main' into compile-time-boo
StephanTLavavej Sep 27, 2025
e74a9e1
TEST_CONSTEXPR => CONSTEXPR20
StephanTLavavej Sep 27, 2025
d80358a
Switch between constexpr and inline.
StephanTLavavej Sep 27, 2025
8f94200
Fix comments.
StephanTLavavej Sep 27, 2025
162d552
Avoid conditional operator to perma-workaround VSO-2582871.
StephanTLavavej Sep 27, 2025
7302f52
Split up test_copy() so we don't need to skip it for Clang debug.
StephanTLavavej Sep 27, 2025
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6 changes: 5 additions & 1 deletion stl/inc/vector
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Original file line number Diff line number Diff line change
Expand Up @@ -3738,7 +3738,11 @@ _NODISCARD _CONSTEXPR20 _VbIt _Find_vbool(_VbIt _First, const _VbIt _Last, const
const auto _SourceMask = _FirstSourceMask & _LastSourceMask;
const auto _SelectVal = (_Val ? *_VbFirst : ~*_VbFirst) & _SourceMask;
const auto _Count = _Countr_zero(_SelectVal);
return _Count == _VBITS ? _Last : _First + static_cast<_Iter_diff_t<_VbIt>>(_Count - _First._Myoff);
if (_Count == _VBITS) {
return _Last;
} else {
return _First + static_cast<_Iter_diff_t<_VbIt>>(_Count - _First._Myoff);
}
}

const auto _FirstVal = (_Val ? *_VbFirst : ~*_VbFirst) & _FirstSourceMask;
Expand Down
77 changes: 57 additions & 20 deletions tests/std/tests/GH_000625_vector_bool_optimization/test.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,12 @@
#include <random>
#include <vector>

#if _HAS_CXX20
#define CONSTEXPR20 constexpr
#else
#define CONSTEXPR20 inline
#endif

#pragma warning(disable : 4365) // conversion from 'unsigned __int64' to 'const __int64', signed/unsigned mismatch

using namespace std;
Expand All @@ -20,7 +26,7 @@ constexpr int blockSize = 32;
static_assert(blockSize == _VBITS, "Invalid block size");

// This test data is not random, but irregular enough to ensure confidence in the tests
const vector<bool> source = { //
constexpr bool source_raw[] = { //
true, false, true, false, true, true, true, false, //
true, false, true, false, true, true, true, false, //
true, false, true, false, true, true, true, false, //
Expand All @@ -39,8 +45,7 @@ const vector<bool> source = { //
true, false, true, false, true, true, true, false, //
true, false, true, false, true, true, true, false};


void test_fill_helper(const size_t length) {
CONSTEXPR20 void test_fill_helper(const size_t length) {
// No offset
{
vector<bool> result_true(length, true);
Expand Down Expand Up @@ -102,7 +107,7 @@ void test_fill_helper(const size_t length) {
}
}

bool test_fill() {
CONSTEXPR20 bool test_fill() {
// Empty
test_fill_helper(0);

Expand All @@ -126,7 +131,7 @@ bool test_fill() {
return true;
}

void test_find_helper(const size_t length) {
CONSTEXPR20 void test_find_helper(const size_t length) {
// No offset
{
vector<bool> input_true(length + 3, false);
Expand Down Expand Up @@ -160,7 +165,7 @@ void test_find_helper(const size_t length) {
}
}

bool test_find() {
CONSTEXPR20 bool test_find() {
// Empty range
test_find_helper(0);

Expand All @@ -178,10 +183,11 @@ bool test_find() {
return true;
}

void test_count_helper(const ptrdiff_t length) {
CONSTEXPR20 void test_count_helper(const ptrdiff_t length) {
const vector<bool> source(begin(source_raw), end(source_raw));
const int counts_true[] = {0, 1, 1, 2, 2, 3, 4, 5};
const int counts_false[] = {0, 0, 1, 1, 2, 2, 2, 2};
const auto expected = div(static_cast<int>(length), 8);
const div_t expected = {static_cast<int>(length) / 8, static_cast<int>(length) % 8};
// No offset
{
const auto result_true = static_cast<int>(count(source.cbegin(), next(source.cbegin(), length), true));
Expand All @@ -203,7 +209,7 @@ void test_count_helper(const ptrdiff_t length) {
}
}

bool test_count() {
CONSTEXPR20 bool test_count() {
// Empty range
test_count_helper(0);

Expand Down Expand Up @@ -259,7 +265,7 @@ void test_huge_vector_bool() {
assert(count(v.begin(), v.end(), false) == large_bit_diff - 3);
}

void test_copy_no_offset(const size_t length) {
CONSTEXPR20 void test_copy_no_offset(const size_t length) {
vector<bool> result;
switch (length) {
case 3:
Expand Down Expand Up @@ -304,6 +310,8 @@ void test_copy_no_offset(const size_t length) {
assert(false);
}

const vector<bool> source(begin(source_raw), end(source_raw));

{
vector<bool> dest(length, false);
const auto res_copy = copy(source.begin(), next(source.begin(), length), dest.begin());
Expand Down Expand Up @@ -341,7 +349,7 @@ void test_copy_no_offset(const size_t length) {
}
}

void test_copy_offset_source(const size_t length) {
CONSTEXPR20 void test_copy_offset_source(const size_t length) {
vector<bool> result;
switch (length) {
case 3:
Expand Down Expand Up @@ -389,6 +397,8 @@ void test_copy_offset_source(const size_t length) {
assert(false);
}

const vector<bool> source(begin(source_raw), end(source_raw));

{
vector<bool> dest(length, false);
const auto res_copy = copy(next(source.begin()), next(source.begin(), length + 1), dest.begin());
Expand Down Expand Up @@ -427,7 +437,7 @@ void test_copy_offset_source(const size_t length) {
}
}

void test_copy_offset_dest(const size_t length) {
CONSTEXPR20 void test_copy_offset_dest(const size_t length) {
vector<bool> result;
switch (length) {
case 3:
Expand Down Expand Up @@ -480,6 +490,8 @@ void test_copy_offset_dest(const size_t length) {
assert(false);
}

const vector<bool> source(begin(source_raw), end(source_raw));

{
vector<bool> dest(length + 1, false);
const auto res_copy = copy(source.begin(), next(source.begin(), length), next(dest.begin()));
Expand Down Expand Up @@ -517,7 +529,7 @@ void test_copy_offset_dest(const size_t length) {
}
}

void test_copy_offset_match(const size_t length) {
CONSTEXPR20 void test_copy_offset_match(const size_t length) {
vector<bool> result;
switch (length) {
case 3:
Expand Down Expand Up @@ -570,6 +582,8 @@ void test_copy_offset_match(const size_t length) {
assert(false);
}

const vector<bool> source(begin(source_raw), end(source_raw));

{
vector<bool> dest(length, false);
const auto res_copy = copy(next(source.begin()), next(source.begin(), length), next(dest.begin()));
Expand Down Expand Up @@ -608,7 +622,7 @@ void test_copy_offset_match(const size_t length) {
}
}

void test_copy_offset_mismatch_leftshift(const size_t length) {
CONSTEXPR20 void test_copy_offset_mismatch_leftshift(const size_t length) {
vector<bool> result;
switch (length) {
case 3:
Expand Down Expand Up @@ -661,6 +675,8 @@ void test_copy_offset_mismatch_leftshift(const size_t length) {
assert(false);
}

const vector<bool> source(begin(source_raw), end(source_raw));

{
vector<bool> dest(length + 1, false);
const auto res_copy = copy(next(source.begin()), next(source.begin(), length), next(dest.begin(), 2));
Expand Down Expand Up @@ -699,7 +715,7 @@ void test_copy_offset_mismatch_leftshift(const size_t length) {
}
}

void test_copy_offset_mismatch_rightshift(const size_t length) {
CONSTEXPR20 void test_copy_offset_mismatch_rightshift(const size_t length) {
vector<bool> result;
switch (length) {
case 3:
Expand Down Expand Up @@ -754,6 +770,8 @@ void test_copy_offset_mismatch_rightshift(const size_t length) {
assert(false);
}

const vector<bool> source(begin(source_raw), end(source_raw));

{
vector<bool> dest(length, false);
const auto res_copy = copy(next(source.begin(), 2), next(source.begin(), length + 1), next(dest.begin()));
Expand Down Expand Up @@ -792,7 +810,7 @@ void test_copy_offset_mismatch_rightshift(const size_t length) {
}
}

void test_copy_offset_aligned(const size_t length) {
CONSTEXPR20 void test_copy_offset_aligned(const size_t length) {
vector<bool> result;
switch (length) {
case 3:
Expand Down Expand Up @@ -845,6 +863,8 @@ void test_copy_offset_aligned(const size_t length) {
assert(false);
}

const vector<bool> source(begin(source_raw), end(source_raw));

{
vector<bool> dest(length, false);
const auto res_copy = copy(next(source.begin(), 9), next(source.begin(), length + 8), next(dest.begin()));
Expand Down Expand Up @@ -883,7 +903,9 @@ void test_copy_offset_aligned(const size_t length) {
}
}

void test_copy_sub_char() {
CONSTEXPR20 void test_copy_sub_char() {
const vector<bool> source(begin(source_raw), end(source_raw));

{ // sub char copy unaligned
const vector<bool> result = {false, false, true, false, true, false, false, false};

Expand Down Expand Up @@ -1092,7 +1114,7 @@ void test_copy_sub_char() {
}
}

void test_copy_regression() {
CONSTEXPR20 void test_copy_regression() {
// This specific case was found by the randomized coverage below.
const vector<bool> src = {0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 1, 0,
1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 0, 1, 0, 0,
Expand All @@ -1115,7 +1137,8 @@ void test_copy_regression() {
assert(dst == correct);
}

bool test_copy() {
// Test copy() in multiple parts to stay within constexpr step limits.
CONSTEXPR20 bool test_copy_part_1() {
test_copy_no_offset(3);
test_copy_no_offset(8);
test_copy_no_offset(22);
Expand Down Expand Up @@ -1144,6 +1167,10 @@ bool test_copy() {
test_copy_offset_match(32);
test_copy_offset_match(67);

return true;
}

CONSTEXPR20 bool test_copy_part_2() {
test_copy_offset_mismatch_leftshift(3);
test_copy_offset_mismatch_leftshift(8);
test_copy_offset_mismatch_leftshift(22);
Expand Down Expand Up @@ -1354,13 +1381,23 @@ static_assert(test_gh_5345<64>());
static_assert(test_gh_5345<64, 16>());
static_assert(test_gh_5345<120>());
static_assert(test_gh_5345<120, 31>());

static_assert(test_fill());
static_assert(test_find());
static_assert(test_count());

#if defined(__clang__) || defined(__EDG__) // TRANSITION, VSO-2574489
static_assert(test_copy_part_1());
static_assert(test_copy_part_2());
#endif // ^^^ no workaround ^^^
#endif // _HAS_CXX20

int main() {
test_fill();
test_find();
test_count();
test_copy();
test_copy_part_1();
test_copy_part_2();

test_huge_vector_bool();

Expand Down