With the df branch merge we got duplicate uses of dump file letters ('z' at least) and some of the letters used are not documented as well.
-- Summary: RTL dump file letters hosed and partly undocumented Product: gcc Version: 4.3.0 Status: UNCONFIRMED Keywords: documentation Severity: normal Priority: P3 Component: other AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: rguenth at gcc dot gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35094