[PATCH][_GLIBCXX_DEBUG] Limit performance impact in __erase_nodes_if
Jonathan Wakely
jwakely@redhat.com
Fri Nov 19 10:43:24 GMT 2021
On Thu, 18 Nov 2021 at 22:05, François Dumont via Libstdc++ <
libstdc++@gcc.gnu.org> wrote:
> Hi
>
> Here is a proposal to limit performance impact of _GLIBCXX_DEBUG
> mode on __erase_nodes_if.
>
> As you can see I am adding erase overloads on the Debug container
> to accept base iterators. So it exposes an additional non-Standard
> method, do you think it is any issue.
>
I think this is fine - I can't think of a way that this could make user
code do the wrong thing.
>
> Note that I've started doing something similar for the vector/deque
> adding this time erase(_Base_const_iterator, _Base_const_iterator)
> overloads. But in this case it results in ambiguous erase calls, even if
> I remove the _Safe_iterator cast operator to the base iterator.
>
> libstdc++: [_GLIBCXX_DEBUG] Reduce performance impact on std::erase_if
>
> Bypass the _GLIBCXX_DEBUG additional checks in
> std::__detail::__erase_node_if used
> by all implementations of std::erase_if for node based containers.
>
> libstdc++-v3/ChangeLog:
>
> * include/bits/erase_if.h (__erase_nodes_if): Add
> _UnsafeContainer template
> parameter. Use it to get iterators to work with.
> * include/debug/macros.h (__glibcxx_check_erase2): New.
> * include/debug/map.h (map<>::erase(_Base_const_iterator)):
> New.
> (map<>::erase(const_iterator)): Use latter.
> * include/debug/multimap.h
> (multimap<>::erase(_Base_const_iterator)): New.
> (multimap<>::erase(const_iterator)): Use latter.
> * include/debug/multiset.h
> (multiset<>::erase(_Base_const_iterator)): New.
> (multiset<>::erase(const_iterator)): Use latter.
> * include/debug/set.h (set<>::erase(_Base_const_iterator)):
> New.
> (set<>::erase(const_iterator)): Use latter.
> * include/debug/unordered_map
> (unordered_map<>::erase(_Base_const_iterator)): New.
> (unordered_multimap<>::erase(const_iterator)): New.
> * include/debug/unordered_set
> (unordered_set<>::erase(_Base_const_iterator)): New.
> (unordered_multiset<>::erase(const_iterator)): New.
> * include/experimental/map (erase_if): Adapt.
> * include/experimental/set (erase_if): Adapt.
> * include/experimental/unordered_map (erase_if): Adapt.
> * include/experimental/unordered_set (erase_if): Adapt.
> * include/std/map (erase_if): Adapt.
> * include/std/set (erase_if): Adapt.
> * include/std/unordered_map (erase_if): Adapt.
> * include/std/unordered_set (erase_if): Adapt.
>
> Tested under Linux x86_64,
>
> Ok to commit ?
>
OK, thanks.
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