backport: re PR rtl-optimization/42389 (ICE in advance_state_on_fence with sel-schd...

backport: re PR rtl-optimization/42389 (ICE in advance_state_on_fence with sel-schd for 175.vpr)

Backport from mainline:
        PR rtl-optimization/42389
         * sel-sched.c (advance_one_cycle): Set FENCE_ISSUE_MORE
         to can_issue_more.
         (advance_state_on_fence): Likewise.
         (sel_target_adjust_priority): Print debug output only when
         sched_verbose >= 4, not 2.
         (get_expr_cost): Do not issue all unique insns on the next cycle.
         (fill_insns): Initialize can_issue_more from the value saved
         with the fence.
         * sel-sched-ir.c (flist_add): New parameter issue_more.
         Init FENCE_ISSUE_MORE with it.
         (merge_fences): Likewise.
         (init_fences): Update call to flist_add.
         (add_to_fences, add_clean_fence_to_fences)
         (add_dirty_fence_to_fences): Likewise.
         (move_fence_to_fences): Update call to merge_fences.
         (invoke_reorder_hooks): Do not reset can_issue_more on insns from
         sched groups.
         * sel-sched-ir.h (struct _fence): New field issue_more.
         (FENCE_ISSUE_MORE): New accessor macro.

From-SVN: r163508