re PR target/43603 (gcc-4.4.3 ICE on ia64 with -O3)

        PR target/43603
        * haifa-sched.c (sched_create_recovery_edges): Update
        dominator info.
        * sel-sched-ir.c (maybe_tidy_empty_bb): Update dominator info
        after deleting an empty block.
        (tidy_control_flow): Also verify dominators.
        (sel_remove_bb): Update dominator info after removing a block.
        (sel_redirect_edge_and_branch_force): Assert that no unreachable
        blocks will be created. Update dominator info.
        (sel_redirect_edge_and_branch): Update dominator info when
        basic blocks do not become unreachable.
        (sel_remove_loop_preheader): Update dominator info.

From-SVN: r167588