On 10 January 2013 21:02, François Dumont wrote: > Hi > > Here is an other version of this patch. Indeed there were no need to > expose many stuff public. Inheriting from _Hash_code_base is fine, it is not > final and it deals with EBO itself. I only kept usage of > _Hashtable_ebo_helper when embedding H2 functor. As it is an extension we > could have impose it not to be final but it doesn't cost a lot to deal with > it. Finally I only needed a single friend declaration to get access to the > H2 part of _Hash_code_base.
OK. > I didn't touch the default cache policy for the moment except reducing > constraints on the hash functor. I prefer to submit an other patch to change > when we cache or not depending on the hash functor expected performance. OK. The reduced constraints are good. Does this actually affect performance? In my tests it doesn't, so I assume we still need to change the caching decision to notice any performance improvements? (Do the performance benchmarks actually tell us anything useful? When I run them I get such varying results it doesn't seem to be reliable.) > I also took the time to replace some typedef expressions with using > ones. I really know what is the rule about using one or the other but I > remembered that Benjamin spent quite some time changing typedef in using so > I prefer to stick to this approach in this file, even if there are still > some typedef left. OK, that doesn't make any difference so isn't important which is used. > Tested under linux x86_64 normal and debug modes. > > 2013-01-10 François Dumont <fdum...@gcc.gnu.org> > > > * include/bits/hashtable_policy.h (_Local_iterator_base): Use > _Hashtable_ebo_helper to embed necessary functors into the > local_iterator when necessary. Pass information about functors Repeating "necessary" seems unnecessary here :) > involved in hash code by copy. > * include/bits/hashtable.h (__cache_default): Do not cache for > builtin integral types unless the hash functor is not noexcept > qualified or is not default constructible. Adapt static assertions > and local iteraror instantiations. ^^ "iteraror" + // When hash codes are not cached local iterator inherits from + // __hash_code_base above to compute node bucket index so it has to be + // default constructible. + static_assert(__if_hash_not_cached< + is_default_constructible<__hash_code_base>>::value, + "Cache the hash code or make functors involved in hash code" + " and bucket index computation default constructibles"); "constructible" not "constructibles" This is OK for trunk, but not 4.7
