[AArch64] Properly handle simple arith+extend ops in rtx costs

	* config/aarch64/aarch64.c (aarch64_rtx_arith_op_extract_p):
	Handle simple SIGN_EXTEND or ZERO_EXTEND.
	(aarch64_rtx_costs): Properly strip extend or extract before
	passing down to rtx costs again.

From-SVN: r226309

gcc/ChangeLog

+2015-07-28  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+	* config/aarch64/aarch64.c (aarch64_rtx_arith_op_extract_p):
+	Handle simple SIGN_EXTEND or ZERO_EXTEND.
+	(aarch64_rtx_costs): Properly strip extend or extract before
+	passing down to rtx costs again.
+
 2015-07-28  Nick Clifton  <nickc@redhat.com>
 
 	* config/rl78/rl78.c (rl78_addsi3_internal): New function.

gcc/config/aarch64/aarch64.c

@@ -5617,6 +5617,11 @@ aarch64_rtx_arith_op_extract_p (rtx x, machine_mode mode)
 	  return true;
 	}
     }
+  /* The simple case <ARITH>, XD, XN, XM, [us]xt.
+     No shift.  */
+  else if (GET_CODE (x) == SIGN_EXTEND
+	   || GET_CODE (x) == ZERO_EXTEND)
+    return REG_P (XEXP (x, 0));
 
   return false;
 }
@@ -6128,7 +6133,8 @@ cost_minus:
 	    if (speed)
 	      *cost += extra_cost->alu.extend_arith;
 
-	    *cost += rtx_cost (XEXP (XEXP (op1, 0), 0), VOIDmode,
+	    op1 = aarch64_strip_extend (op1);
+	    *cost += rtx_cost (op1, VOIDmode,
 			       (enum rtx_code) GET_CODE (op1), 0, speed);
 	    return true;
 	  }
@@ -6206,7 +6212,8 @@ cost_plus:
 	    if (speed)
 	      *cost += extra_cost->alu.extend_arith;
 
-	    *cost += rtx_cost (XEXP (XEXP (op0, 0), 0), VOIDmode,
+	    op0 = aarch64_strip_extend (op0);
+	    *cost += rtx_cost (op0, VOIDmode,
 			       (enum rtx_code) GET_CODE (op0), 0, speed);
 	    return true;
 	  }