2018-09-03  John David Anglin  <danglin@gcc.gnu.org>

	PR rtl-optimization/85458
	* sel-sched.c (sel_target_adjust_priority): Allow backend adjust
	priority hook to reduce the priority of EXPR.

Index: sel-sched.c
===================================================================
--- sel-sched.c	(revision 264045)
+++ sel-sched.c	(working copy)
@@ -3330,11 +3330,11 @@
   else
     new_priority = priority;
 
+  gcc_assert (new_priority >= 0);
+
   /* If the priority has changed, adjust EXPR_PRIORITY_ADJ accordingly.  */
   EXPR_PRIORITY_ADJ (expr) = new_priority - EXPR_PRIORITY (expr);
 
-  gcc_assert (EXPR_PRIORITY_ADJ (expr) >= 0);
-
   if (sched_verbose >= 4)
     sel_print ("sel_target_adjust_priority: insn %d,  %d+%d = %d.\n",
 	       INSN_UID (EXPR_INSN_RTX (expr)), EXPR_PRIORITY (expr),