On 15 November 2017 at 17:38, Jason Arnold wrote: > The GCC7 notes says > > - A new power-of-two rehashing policy for use with the _Hashtable internals, > thanks to François Dumont. > > What do I have to do to use this instead of the default prime rehash > policy, for example with std::unordered_set/map? You can't use it with unordered_map, because there's no way to change the rehash policy. You'd need to use the _Hashtable type directly, rather than via unordered_set.