[Bug tree-optimization/18587] New: build_v_may_defs and build_vuses should be hastables instead of varray

["pinskia at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

For PR 15855 we see that the tree aliasing analysis is slow:
 tree alias analysis   :  24.22 ( 6%) usr   0.75 ( 2%) sys  26.57 ( 5%) wall

9% of the total time is spent looking at for if something is in either build_v_may_defs or build_vuses.

-- 
           Summary: build_v_may_defs and build_vuses should be hastables
                    instead of varray
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Keywords: compile-time-hog
          Severity: minor
          Priority: P2
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org
                CC: dnovillo at gcc dot gnu dot org,gcc-bugs at gcc dot gnu
                    dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18587