[Bug libstdc++/54075] [4.7.1] unordered_map insert 3x slower than 4.6.2

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54075

--- Comment #19 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-07-27 
00:32:54 UTC ---
Testcase please.