expr.c (expand_expr_real_2): Re-cost if previous costs are the same.

2017-04-26  Tamar Christina  <tamar.christina@arm.com>

	* expr.c (expand_expr_real_2): Re-cost if previous costs are the same.

From-SVN: r247505

gcc/ChangeLog

+2017-04-26  Tamar Christina  <tamar.christina@arm.com>
+
+	* expr.c (expand_expr_real_2): Re-cost if previous costs are the same.
+
 2017-04-27  Tamar Christina  <tamar.christina@arm.com>
 
 	* simplify-rtx.c (simplify_binary_operation_1): Add LSHIFTRT case.

gcc/expr.c

@@ -8838,6 +8838,15 @@ expand_expr_real_2 (sepops ops, rtx target, machine_mode tmode,
 	   end_sequence ();
 	   unsigned uns_cost = seq_cost (uns_insns, speed_p);
 	   unsigned sgn_cost = seq_cost (sgn_insns, speed_p);
+
+	   /* If costs are the same then use as tie breaker the other
+	      other factor.  */
+	   if (uns_cost == sgn_cost)
+	     {
+		uns_cost = seq_cost (uns_insns, !speed_p);
+		sgn_cost = seq_cost (sgn_insns, !speed_p);
+	     }
+
 	   if (uns_cost < sgn_cost || (uns_cost == sgn_cost && unsignedp))
 	     {
 	       emit_insn (uns_insns);