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[libcxx] Avoid hash key in __hash_table::find() if it is empty. #126837

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Merged
merged 10 commits into from
Jul 3, 2025
Merged

[libcxx] Avoid hash key in __hash_table::find() if it is empty. #126837

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0f93eba
[libcxx] Avoid hash key in __hash_table::find() if no buckets yet.
arbiny Feb 11, 2025
a2f7b3c
Add benchmarks.
arbiny Feb 13, 2025
96ef4a1
Fix clang-format issue.
arbiny Feb 14, 2025
bc3ce69
Add license header and UNSUPPORTED
arbiny Feb 14, 2025
0102da7
Add size check to __hash_table::find() and update benchmark cases
arbiny Feb 17, 2025
1de7487
Move benchmarks for querying on empty containers to the generic tests
arbiny May 8, 2025
b3faeac
Update associative_container_benchmarks
arbiny May 18, 2025
823b92e
Fix clang-format issues.
arbiny May 19, 2025
953ea5e
Remove some std::string instantiation benchmarks to reduce total time
arbiny May 21, 2025
b85f399
Merge branch 'main' into hash_table_find_opt
xbcnn Jun 10, 2025
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4 changes: 2 additions & 2 deletions libcxx/include/__hash_table
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Original file line number Diff line number Diff line change
Expand Up @@ -1771,9 +1771,9 @@ template <class _Tp, class _Hash, class _Equal, class _Alloc>
template <class _Key>
typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
__hash_table<_Tp, _Hash, _Equal, _Alloc>::find(const _Key& __k) {
size_t __hash = hash_function()(__k);
size_type __bc = bucket_count();
if (__bc != 0) {
size_t __hash = hash_function()(__k);
size_t __chash = std::__constrain_hash(__hash, __bc);
__next_pointer __nd = __bucket_list_[__chash];
if (__nd != nullptr) {
Expand All @@ -1792,9 +1792,9 @@ template <class _Tp, class _Hash, class _Equal, class _Alloc>
template <class _Key>
typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator
__hash_table<_Tp, _Hash, _Equal, _Alloc>::find(const _Key& __k) const {
size_t __hash = hash_function()(__k);
size_type __bc = bucket_count();
if (__bc != 0) {
size_t __hash = hash_function()(__k);
size_t __chash = std::__constrain_hash(__hash, __bc);
__next_pointer __nd = __bucket_list_[__chash];
if (__nd != nullptr) {
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