The thread starts here: http://gcc.gnu.org/ml/gcc/2007-11/msg00791.html
In addition, I observe the same behaviour when building a native, SJLJ version of libgnat on x86_64. Krister Walfridsson says: "The problem was introduced by revision 125624 (the dataflow merge).". -- Summary: [4.3 regression] gnat1 takes too long to compile g- catiio.adb with SJLJ exceptions Product: gcc Version: 4.3.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: ada AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: ludovic at ludovic-brenta dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34400