See the discussion started with this message: http://gcc.gnu.org/ml/gcc/2005-10/msg00808.html
According to Jim Wilson in http://gcc.gnu.org/ml/gcc/2005-10/msg00858.html, we now have the infrastructure to properly encode prologues / epilogues. The ia64 port is using this. -- Summary: various targets: GCC fails to encode epilogues in unwind-info Product: gcc Version: 4.3.0 Status: UNCONFIRMED Keywords: wrong-code, meta-bug, EH, wrong-debug Severity: normal Priority: P3 Component: target AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: amylaar at gcc dot gnu dot org BugsThisDependsOn: 18749 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29997