http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51860
--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-01-15 21:01:23 UTC --- Well, DEBUG_INSNs aren't in the stream during the reorg anymore, it is about the NOTE_INSN_VAR_LOCATION and NOTE_INSN_CALL_ARG_LOCATION (apparently the latter in this testcase) in the stream that make the chunkify code insert it at different spots.
