Re: [PATCH] libstdc++: Limit allocations in _Rb_tree

["François Dumont" <frs.dumont@gmail.com>]

Do not bother reviewing this for the moment, some tests are failing.


On 02/02/23 19:20, François Dumont wrote:
> This is PR 96088 but this time for _Rb_tree based containers.
>
> I guess it won't go in for the moment but I wanted to submit it 
> already because of the changes I had to do in stl_functions.h. It 
> sounds like missing parts for C++11 move-semantic. I still need to run 
> all tests to see if they can have side effects.
>
>      libstdc++: [_Rb_tree] Limit allocation on iterator insertion [PR 
> 96088]
>
>     Detect when invoking the comparer require an allocation and in 
> this case
>     create a temporary instance that will be moved to storage location 
> if the
>     insertion eventually takes place. Avoid to allocate a node otherwise.
>
>     libstdc++-v3/ChangeLog:
>
>             PR libstdc++/96088
>             * include/bits/stl_function.h
>             (std::less<>::operator()): Add noexcept qualification.
>             (std::greater::operator()): Likewise.
> (std::_Identity<>::operator<_Tp2>(_Tp2&&)): New perfect forwarding 
> operator.
> (std::_Select1st<>::operator<_Pair2>(_Pair2&&)): New move operator.
>             * include/bits/stl_tree.h 
> (_Rb_tree<>::_ConvertToValueType<>): New helper type.
>             (_Rb_tree<>::_M_get_insert_unique_pos_tr): New.
>             (_Rb_tree<>::_S_forward_key): New.
>             (_Rb_tree<>::_M_emplace_unique_kv): New.
>             (_Rb_tree<>::_M_emplace_unique_aux): New, use latter.
>             (_Rb_tree<>::_M_emplace_unique): New, use latter.
>             * testsuite/23_containers/map/96088.cc: New test case.
>             * testsuite/23_containers/multimap/96088.cc: New test case.
>             * testsuite/23_containers/multiset/96088.cc: New test case.
>             * testsuite/23_containers/set/96088.cc: New test case.
>
> Ok to commit ?
>
> François
>