[Bug libstdc++/50257] [C++0x] unordered_map slow initialization due to huge __prime_list

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50257

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|unordered_map slow          |[C++0x] unordered_map slow
                   |initialization due to huge  |initialization due to huge
                   |__prime_list                |__prime_list

--- Comment #1 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-09-01 09:06:47 UTC ---
Indeed, this is the right place to ask, but also consider the mailing list for
anything not strictly speaking a bug but an enhancement. Anyway, to begin with,
we can definitely special case the default value of 10 and avoid the
lower_bound call, seems a sensible optimization anyway, but to be honest I'm a
bit surprised that you can see that in the profile vs, eg, the time spent
allocating memory in _M_allocate_buckets immediately afterward. Can you clarify
this?