The test case gcc-c-torture/compile/limits-fnargs.c takes multiple hours to compile at -O2 or above optimization on IA64. It looks like most of the time is spent in IRA. The IRA pass calls reload which calls ira_sort_regnos_for_alter_reg with n = 28977. This in turn calls coalesce_spill_slots with num = 10061. It is in the main loop of coalesce_spill_slots where I seem to spend a most of the time compiling limits-fnargs.c.
-- Summary: limits-fnargs.c takes very long time to compile at -O2 Product: gcc Version: 4.4.0 Status: UNCONFIRMED Keywords: compile-time-hog Severity: normal Priority: P3 Component: middle-end AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: sje at cup dot hp dot com GCC target triplet: ia64-*-* http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37790