e3ef832a9e
When hasher is identified as slow and the number of elements is limited in the container use a brute-force loop on those elements to look for a given key using the key_equal functor. For the moment the default threshold to consider the container as small is 20. libstdc++-v3/ChangeLog: PR libstdc++/68303 * include/bits/hashtable_policy.h (_Hashtable_hash_traits<_Hash>): New. (_Hash_code_base<>::_M_hash_code(const _Hash_node_value<>&)): New. (_Hashtable_base<>::_M_key_equals): New. (_Hashtable_base<>::_M_equals): Use latter. (_Hashtable_base<>::_M_key_equals_tr): New. (_Hashtable_base<>::_M_equals_tr): Use latter. * include/bits/hashtable.h (_Hashtable<>::__small_size_threshold()): New, use _Hashtable_hash_traits. (_Hashtable<>::find): Loop through elements to look for key if size is lower than __small_size_threshold(). (_Hashtable<>::_M_emplace(true_type, _Args&&...)): Likewise. (_Hashtable<>::_M_insert_unique(_Kt&&, _Args&&, const _NodeGenerator&)): Likewise. (_Hashtable<>::_M_compute_hash_code(const_iterator, const key_type&)): New. (_Hashtable<>::_M_emplace(const_iterator, false_type, _Args&&...)): Use latter. (_Hashtable<>::_M_find_before_node(const key_type&)): New. (_Hashtable<>::_M_erase(true_type, const key_type&)): Use latter. (_Hashtable<>::_M_erase(false_type, const key_type&)): Likewise. * src/c++11/hashtable_c++0x.cc: Include <bits/functional_hash.h>. * testsuite/util/testsuite_performance.h (report_performance): Use 9 width to display memory. * testsuite/performance/23_containers/insert_erase/unordered_small_size.cc: New performance test case. |
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| .. | ||
| 20_util/memory_resource | ||
| 21_strings | ||
| 22_locale | ||
| 23_containers | ||
| 25_algorithms | ||
| 26_numerics | ||
| 27_io | ||
| 28_regex | ||
| 29_atomics | ||
| 30_threads/future | ||
| ext/pb_ds | ||