[PATCH] insn priority adjustments in scheduler and rs6000 port

[David Edelsohn]

      * sched-rgn.c (init_ready_list): add invocations to
      targetm.sched.adjust_priority.
      * haifa-sched.c (sched_max_insns_priority): new global
      variable. Defined here, used in config/rs6000/rs6000.c.

      * config/rs6000/rs6000.h:
      (rs6000_sched_restricted_insns_priority_str): support new
      flag -mprioritize-restricted-insns.
      (DEFAULT_RESTRICTED_INSNS_PRIORITY): Define.
      * config/rs6000/rs6000.c (is_dispatch_slot_restricted): New
       function.
      (rs6000_adjust_priority): change priority of restricted
      insns, using above new function and new flag.

The rs6000 changes are fine.

	Are the general scheduler changes okay with you, Vlad, and whoever
can approve them?

Thanks, David