tree-ssa-threadupdate.c: Replace REDIRECTION_DATA varray with a hash table.

tree-ssa-threadupdate.c: Replace REDIRECTION_DATA varray with a hash table.

        * tree-ssa-threadupdate.c: Replace REDIRECTION_DATA varray with
        a hash table.  Extensive modifications throughout to support
        that change.
        (struct el): New.
        (struct local_info): New.
        (struct redirection_data): Add new INCOMING_EDGES and DO_NOT_DUPLICATE
        fields.
        (redirection_data): Now a hashtable.
        (redirection_data_hash, redirection_data_eq): New.
        (lookup_redirection_data, create_duplicates): New.
        (create_edge_and_update_destionation_phis): New.
        (fixup_template_block, redirect_edges): New.
        (thread_block): Use hash table traversals instead of loops over
        varray entries or incoming edge vectors.

From-SVN: r90941