https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96088
François Dumont <fdumont at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Target Milestone|--- |12.0 Resolution|--- |FIXED Status|ASSIGNED |RESOLVED --- Comment #6 from François Dumont <fdumont at gcc dot gnu.org> --- Fix with this commit: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=2c43f5ec9db163696de8691eb529df06c4999bcc libstdc++: Limit allocation on iterator insertion in Hashtable [PR 96088] When inserting into unordered_multiset or unordered_multimap first instantiate the node to store and compute the hash code from it to avoid a potential intermediate key_type instantiation. When inserting into unordered_set or unordered_map check if invoking the hash functor with container key_type is noexcept and invoking the same hash functor with key part of the iterator value_type can throw. In this case create a temporary key_type instance at Hashtable level and use it to compute the hash code. This temporary instance is moved to the final storage location if needed. libstdc++-v3/ChangeLog: PR libstdc++/96088 * include/bits/hashtable_policy.h (_Select2nd): New. (_NodeBuilder<>): New. (_ReuseOrAllocNode<>::operator()): Use variadic template args. (_AllocNode<>::operator()): Likewise. * include/bits/hashtable.h (_Hashtable<>::__node_builder_t): New. (_Hashtable<>::_M_insert_unique<>(_Kt&&, _Arg&&, const _NodeGenerator&)): New. (_Hashtable<>::_S_forward_key): New. (_Hashtable<>::_M_insert): Use latter. (_Hashtable<>::_M_insert(const_iterator, _Arg&&, const _NodeGenerator&, false_type)): Instantiate node first, compute hash code second. * testsuite/23_containers/unordered_map/96088.cc: New test. * testsuite/23_containers/unordered_multimap/96088.cc: New test. * testsuite/23_containers/unordered_multiset/96088.cc: New test. * testsuite/23_containers/unordered_set/96088.cc: New test. * testsuite/util/replacement_memory_operators.h (counter::_M_increment): New. (counter::_M_decrement): New. (counter::reset()): New.