flow.c (update_life_info): Consider blocks null to mean the universal set.

flow.c (update_life_info): Consider blocks null to mean the universal set.

        * flow.c (update_life_info): Consider blocks null to mean the
        universal set.
        (calculate_global_regs_live): Likewise.
        (life_analysis): Do that instead of collecting all_blocks.

From-SVN: r33469