* haifa-sched.c (ok_for_early_schedule): New function.
        (early_queue_to_ready): New function.
        (schedule_block): Allow early removal of insns from Q.
        (schedule_insn): Update INSN_TICK in case of premature
        issue.
        * common.opt (sched_stalled_insns): New flag.
        (sched_stalled_insns_dep): New flag.
        * flags.h: Same above flags.
        * opts.c: Same as above.
        * toplev.c: Same as above.
        * target.h (targetm.sched.is_costly_dependence): New
        hook.
        * target-def.h: Same as above.
        * config/rs6000/rs6000.h: (rs6000_sched_costly_dep):
        Support new flag -msched-costly-dep.
        (DEFAULT_SCHED_COSTLY_DEP): Define.
        * config/rs6000/rs6000.c:
        (rs6000_is_costly_dependence): New function.
        (is_load_insn, is_store_insn): New functions.
        (is_load_insn1, is_store_insn1, is_mem_ref): New
        functions.
        * doc/invoke.texi (-fsched-stalled-insns-dep)
        (-fsched-stalled-insns, -msched-costly-dep): Document
        options.
        * doc/tm.texi (is_costly_dependence): Define new
        scheduler target hook.

From-SVN: r72261