[AArch64] Use extend_arith rtx cost appropriately

	* config/aarch64/aarch64.c (aarch64_rtx_costs): Use extend_arith
	rather than arith_shift cost when costing ADD/MINUS of an
	extended value.

From-SVN: r222623

gcc/ChangeLog

+2015-04-30  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+	* config/aarch64/aarch64.c (aarch64_rtx_costs): Use extend_arith
+	rather than arith_shift cost when costing ADD/MINUS of an
+	extended value.
+
 2015-04-30  Jan Hubicka  <hubicka@ucw.cz>
 
 	PR lto/65948

gcc/config/aarch64/aarch64.c

@@ -5819,7 +5819,7 @@ cost_minus:
         if (aarch64_rtx_arith_op_extract_p (op1, mode))
 	  {
 	    if (speed)
-	      *cost += extra_cost->alu.arith_shift;
+	      *cost += extra_cost->alu.extend_arith;
 
 	    *cost += rtx_cost (XEXP (XEXP (op1, 0), 0),
 			       (enum rtx_code) GET_CODE (op1),
@@ -5888,7 +5888,7 @@ cost_plus:
         if (aarch64_rtx_arith_op_extract_p (op0, mode))
 	  {
 	    if (speed)
-	      *cost += extra_cost->alu.arith_shift;
+	      *cost += extra_cost->alu.extend_arith;
 
 	    *cost += rtx_cost (XEXP (XEXP (op0, 0), 0),
 			       (enum rtx_code) GET_CODE (op0),