http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53300
--- Comment #16 from David Edelsohn <dje at gcc dot gnu.org> 2012-05-11 15:11:59 UTC --- The mis-compiled file is libcpp/line-map.c. I have attached the pre-processed output for line-map.c on AIX. I also have attached assembly files showing the correct and incorrect output. The difference is: --- line-map.s.good 2012-05-11 11:01:33.000000000 -0400 +++ line-map.s.bad 2012-05-11 11:00:43.000000000 -0400 @@ -4536,26 +4536,6 @@ .byte 10 .byte "Macro line maps" .byte 10, 0 - .space 2 -LC..0: - .byte "LC_ENTER" - .byte 0 - .space 3 -LC..1: - .byte "LC_LEAVE" - .byte 0 - .space 3 -LC..2: - .byte "LC_RENAME" - .byte 0 - .space 2 -LC..3: - .byte "LC_RENAME_VERBATIM" - .byte 0 - .space 1 -LC..4: - .byte "LC_ENTER_MACRO" - .byte 0 .csect _linemap.rw_[RW],4 .align 2 .set LANCHOR..1,$ + 0 which corresponds to enum lc_reason { LC_ENTER = 0, LC_LEAVE, LC_RENAME, LC_RENAME_VERBATIM, LC_ENTER_MACRO };