http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32911
--- Comment #3 from Jan Hubicka <hubicka at ucw dot cz> 2012-05-15 15:57:29 UTC --- Note that I was thinking of similar attribute for C++ iostream initialization code. Currently every unit including iostream gets a call to the iostream constructor. With LTO we merge the constructors together and get _alot_ of redundant calls to the construction code. Declaring that only first call is needed would save some (quite minor) startup overehead. (overhead of iostream startup is large, but after inlning all together it boils down to cca 7000 redundant calls in Mozilla startup that executes quite quickly)