From: François Dumont Date: Mon, 25 Oct 2021 13:59:35 +0000 (+0200) Subject: libstdc++: Unordered containers merge re-use hash code X-Git-Tag: upstream/12.2.0~3420 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=d10b863fa3de8b202aadbdef1b012188ab0868d8;p=platform%2Fupstream%2Fgcc.git libstdc++: Unordered containers merge re-use hash code When merging 2 unordered containers with same hasher we can re-use the hash code from the cache if any. Also in the context of the merge operation on multi-container use previous insert iterator as a hint for the next insert. libstdc++-v3/ChangeLog: * include/bits/hashtable_policy.h: (_Hash_code_base<>::_M_hash_code(const _Hash&, const _Hash_node_value<_Value, true>&)): New. (_Hash_code_base<>::_M_hash_code<_H2>(const _H2&, const _Hash_node_value<>&)): New. * include/bits/hashtable.h (_Hashtable<>::_M_merge_unique): Use latter. (_Hashtable<>::_M_merge_multi): Likewise. * testsuite/23_containers/unordered_multiset/modifiers/merge.cc (test05): New test. * testsuite/23_containers/unordered_set/modifiers/merge.cc (test04): New test. --- diff --git a/libstdc++-v3/include/bits/hashtable.h b/libstdc++-v3/include/bits/hashtable.h index 0e949d7..6e2d4c1 100644 --- a/libstdc++-v3/include/bits/hashtable.h +++ b/libstdc++-v3/include/bits/hashtable.h @@ -1076,7 +1076,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION { auto __pos = __i++; const key_type& __k = _ExtractKey{}(*__pos); - __hash_code __code = this->_M_hash_code(__k); + __hash_code __code + = this->_M_hash_code(__src.hash_function(), *__pos._M_cur); size_type __bkt = _M_bucket_index(__code); if (_M_find_node(__bkt, __k, __code) == nullptr) { @@ -1099,14 +1100,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION node_type>, "Node types are compatible"); __glibcxx_assert(get_allocator() == __src.get_allocator()); + __node_ptr __hint = nullptr; this->reserve(size() + __src.size()); for (auto __i = __src.cbegin(), __end = __src.cend(); __i != __end;) { auto __pos = __i++; - const key_type& __k = _ExtractKey{}(*__pos); - __hash_code __code = this->_M_hash_code(__k); + __hash_code __code + = this->_M_hash_code(__src.hash_function(), *__pos._M_cur); auto __nh = __src.extract(__pos); - _M_insert_multi_node(nullptr, __code, __nh._M_ptr); + __hint = _M_insert_multi_node(__hint, __code, __nh._M_ptr)._M_cur; __nh._M_ptr = nullptr; } } diff --git a/libstdc++-v3/include/bits/hashtable_policy.h b/libstdc++-v3/include/bits/hashtable_policy.h index c0295b7..0b5443f 100644 --- a/libstdc++-v3/include/bits/hashtable_policy.h +++ b/libstdc++-v3/include/bits/hashtable_policy.h @@ -1250,6 +1250,19 @@ namespace __detail return _M_hash()(__k); } + __hash_code + _M_hash_code(const _Hash&, + const _Hash_node_value<_Value, true>& __n) const + { return __n._M_hash_code; } + + // Compute hash code using _Hash as __n _M_hash_code, if present, was + // computed using _H2. + template + __hash_code + _M_hash_code(const _H2&, + const _Hash_node_value<_Value, __cache_hash_code>& __n) const + { return _M_hash_code(_ExtractKey{}(__n._M_v())); } + std::size_t _M_bucket_index(__hash_code __c, std::size_t __bkt_count) const { return _RangeHash{}(__c, __bkt_count); } diff --git a/libstdc++-v3/testsuite/23_containers/unordered_multiset/modifiers/merge.cc b/libstdc++-v3/testsuite/23_containers/unordered_multiset/modifiers/merge.cc index 1ed2ce2..07b8a34 100644 --- a/libstdc++-v3/testsuite/23_containers/unordered_multiset/modifiers/merge.cc +++ b/libstdc++-v3/testsuite/23_containers/unordered_multiset/modifiers/merge.cc @@ -17,6 +17,7 @@ // { dg-do run { target c++17 } } +#include #include #include #include @@ -105,6 +106,26 @@ test04() VERIFY( c2.empty() ); } +void +test05() +{ + const std::unordered_multiset c0{ "abcd", "abcd", "efgh", "efgh", "ijkl", "ijkl" }; + std::unordered_multiset c1 = c0; + std::unordered_set c2( c0.begin(), c0.end() ); + + c1.merge(c2); + VERIFY( c1.size() == (1.5 * c0.size()) ); + for (auto& i : c1) + VERIFY( c1.count(i) == (1.5 * c0.count(i)) ); + VERIFY( c2.empty() ); + + c1.clear(); + c2.insert( c0.begin(), c0.end() ); + c1.merge(std::move(c2)); + VERIFY( c1.size() == (0.5 * c0.size()) ); + VERIFY( c2.empty() ); +} + int main() { @@ -112,4 +133,5 @@ main() test02(); test03(); test04(); + test05(); } diff --git a/libstdc++-v3/testsuite/23_containers/unordered_set/modifiers/merge.cc b/libstdc++-v3/testsuite/23_containers/unordered_set/modifiers/merge.cc index c9c8a60..0e184b1 100644 --- a/libstdc++-v3/testsuite/23_containers/unordered_set/modifiers/merge.cc +++ b/libstdc++-v3/testsuite/23_containers/unordered_set/modifiers/merge.cc @@ -17,6 +17,7 @@ // { dg-do run { target c++17 } } +#include #include #include #include @@ -125,10 +126,52 @@ test03() VERIFY( c2.empty() ); } +void +test04() +{ + const std::unordered_set c0{ "abcd", "efgh", "ijkl", }; + std::unordered_set c1 = c0; + std::unordered_multiset c2( c0.begin(), c0.end() ); + c1.merge(c2); + VERIFY( c1 == c0 ); + VERIFY( equal_elements(c2, c0) ); + + c1.clear(); + c1.merge(c2); + VERIFY( c1 == c0 ); + VERIFY( c2.empty() ); + + c2.merge(c1); + VERIFY( c1.empty() ); + VERIFY( equal_elements(c2, c0) ); + + c1 = c0; + c2.merge(c1); + VERIFY( c1.empty() ); + VERIFY( c2.size() == (2 * c0.size()) ); + VERIFY( c2.count("abcd") == 2 ); + VERIFY( c2.count("efgh") == 2 ); + VERIFY( c2.count("ijkl") == 2 ); + + c1.merge(c2); + VERIFY( c1 == c0 ); + VERIFY( equal_elements(c2, c0) ); + + c1.merge(std::move(c2)); + VERIFY( c1 == c0 ); + VERIFY( equal_elements(c2, c0) ); + + c1.clear(); + c1.merge(std::move(c2)); + VERIFY( c1 == c0 ); + VERIFY( c2.empty() ); +} + int main() { test01(); test02(); test03(); + test04(); }