hashtable local iterator

[Paolo Carlini]

Hi,
>
> 2011-12-24  François Dumont <fdumont@gcc.gnu.org>
>
>         PR libstdc++/51608
>         * include/bits/hashtable_policy.h (_Equal_helper<>): New, 
> change the
>         way the _Equal functor is used depending on whether hash code is
>         cached or not.
>         (_Ebo_helper<>): New helper type to introduce EBO when possible.
>         (_Hash_code_base): Use _Ebo_helper to limit memory footprint. Move
>         _Equal functor management...
>         (_Hashtable_base): ...here, new, use _Equal_helper.
>         (_Local_iterator_base<>, _Locale_iterator<>, 
> _Locale_const_iterator<>):
>         New, use _Hash_code_base, implementation of...
>         * include/bits/hashtable.h (_Hashtable<>::local_iterator,
>         _Hashtable<>::const_local_iterator): ...those. Add static 
> assertions
>         checking that some functors are empty depending on whether 
> hash code
>         is cache or not.
>         (_Hashtable<>::_M_bucket_index): New overloads using current 
> bucket
>         count, use through out the _Hastable<> implementation.
>         * include/bits/unordered_set.h (__unordered_set<>,
>         __unordered_multiset<>): Cache hash code if hash functor is 
> not empty.
>         * include/bits/unordered_map.h (__unordered_map<>,
>         __unordered_multimap<>): Likewise.
>         * include/debug/unordered_map
>         (unordered_map<>::_S_to_local, unordered_multimap<>::_S_to_local):
>         Adapt to match new local iterator implementation.
>         * include/debug/unordered_set (unordered_set<>::_S_to_local,
>         unordered_multiset<>::_S_to_local): Likewise.
>         * include/profile/unordered_map 
> (unordered_map<>::_M_profile_destruct,
>         unordered_multimap<>::_M_profile_destruct): Enhance thanks to 
> usage of
>         local iterators.
>         * include/profile/unordered_set 
> (unordered_set<>::_M_profile_destruct,
>         unordered_multiset<>::_M_profile_destruct): Likewise.
>         * 
> testsuite_files/23_containers/unordered_set/instantiation_neg.cc:
>         Fix error line.
>         * testsuite_files/23_containers/unordered_set/final_hash.cc: New.
>         * 
> testsuite_files/23_containers/unordered_multiset/final_hash.cc: New.
>         * testsuite_files/23_containers/unordered_map/final_hash.cc: New.
>         * 
> testsuite_files/23_containers/unordered_multimap/final_hash.cc: New.
>
> Merry Christmas to you guys.
Merry Christmas and, well, Happy New Year too (for this one I'm not 
late, at least ;) !

Patch looks great to me, as a very minor stylistic nit, for static 
member functions I think it would make sense to have the static keyword 
on the same line of the return type.

Let's wait just one more day or so in order to make sure other people 
get a chance to have a look (somebody may be in vacations) and let's 
resolve the issue.

Thanks again!
Paolo.