http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50430
--- Comment #3 from Jan Hubicka <hubicka at gcc dot gnu.org> 2011-09-22 14:20:07 UTC --- Created attachment 25340 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=25340 reduced testcase This is somewhat reduced testcase. The problem can be a bit illustrated on C. We have something like extern vtable[]={vtable2} where vtable2 sits in other unit and is static. We however know the constructor and it is extern static vtable2[]={function_ptr}; now we can fold vtable[0] to the external vtable2 that we can not reffer in code, but still can fold references into it into function_ptr. now with LTO we decide to not stream vtable initializer and replace it by error_mark losing the knowledge. This is an regression to 4.6 even though it is not too important one.
