PR rtl-optimization/83530

       * sel-sched.c (force_next_insn): New global variable.
       (remove_insn_for_debug): When force_next_insn is true, also leave only
       next insn in the ready list.
       (sel_sched_region): When the region wasn't scheduled, make another pass
       over it with force_next_insn set to 1.

       * gcc.dg/pr83530.c: New test.

From-SVN: r259228