[Bug middle-end/37790] New: limits-fnargs.c takes very long time to compile at -O2

["sje at cup dot hp dot com" <gcc-bugzilla at gcc dot gnu dot org>]

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