[ARM] Fix costing of sign-extending load in rtx costs

	* config/arm/arm.c (arm_new_rtx_costs, SIGN_EXTEND case):
	Don't add cost of inner memory when handling sign-extended
	loads.

From-SVN: r236461

gcc/ChangeLog

+2016-05-19  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+	* config/arm/arm.c (arm_new_rtx_costs, SIGN_EXTEND case):
+	Don't add cost of inner memory when handling sign-extended
+	loads.
+
 2016-05-19  Ilya Enkovich  <ilya.enkovich@intel.com>
 
 	PR rtl-optimization/71148

gcc/config/arm/arm.c

@@ -10762,8 +10762,6 @@ arm_new_rtx_costs (rtx x, enum rtx_code code, enum rtx_code outer_code,
       if ((arm_arch4 || GET_MODE (XEXP (x, 0)) == SImode)
 	  && MEM_P (XEXP (x, 0)))
 	{
-	  *cost = rtx_cost (XEXP (x, 0), VOIDmode, code, 0, speed_p);
-
 	  if (mode == DImode)
 	    *cost += COSTS_N_INSNS (1);