* haifa-sched.c (is_cfg_nonregular): Change return type to
        an int.  No longer compute "estimated" number of edges.  Use
        computed_jump_p instead of duplicating the code.  Fixup/add
        some comments.
        (build_control_flow): Returns a value indicating an irregularity
        in the cfg was detected.  Count the number of edges in the cfg.
        allocate various edge tables.
        (find_rgns): No longer look for unreachable blocks.
        (schedule_insns): Do not allocate memory for edge tables here.
        Free memory for edge tables before returning.  Do not perform
        cross block scheduling if build_control_flow returns nonzero.
        * flow.c (compute_preds_succs): More accurately determine when
        a block drops in.
Fixes various compile hangs after haifa cleanup.

From-SVN: r18439