http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48913
--- Comment #4 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-05-09 09:48:19 UTC --- LTO does indeed partition the program - but the process that does this partitioning reads in (parts of) the whole program, thus this is usually where we require arbitrary amounts of memory. The lto1 process that is involved with that has the -fwpa flag passed. The lto1 processes dealing with partitions have the -fltrans flag passed. Yust FYI.
