decl.c (gnat_to_gnu_entity): Pass correct arguments to create_field_decl.

	* gcc-interface/decl.c (gnat_to_gnu_entity) <E_Array_Type>: Pass
	correct arguments to create_field_decl.  Remove redundant iteration.
	Rewrite computation of the maximum size.
	<E_Array_Subtype>: Reorder and simplify handling of special cases.
	Rewrite computation of the maximum size.  Use consistent naming.
	* gcc-interface/trans.c (Attribute_to_gnu) <Attr_Length>: Swap
	comparison order for consistency.  Use generic integer node to
	build the operator and fold the result.

From-SVN: r148962

gcc/ada/ChangeLog

+2009-06-26  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gcc-interface/decl.c (gnat_to_gnu_entity) <E_Array_Type>: Pass
+	correct arguments to create_field_decl.  Remove redundant iteration.
+	Rewrite computation of the maximum size.
+	<E_Array_Subtype>: Reorder and simplify handling of special cases.
+	Rewrite computation of the maximum size.  Use consistent naming.
+	* gcc-interface/trans.c (Attribute_to_gnu) <Attr_Length>: Swap
+	comparison order for consistency.  Use generic integer node to
+	build the operator and fold the result.
+
 2009-06-25  Vincent Celier  <celier@adacore.com>
 
 	* vms_data.ads: Minor comment change

gcc/ada/gcc-interface/trans.c

@@ -1552,43 +1552,38 @@ Attribute_to_gnu (Node_Id gnat_node, tree *gnu_result_type_p, int attribute)
 		/* We used to compute the length as max (hb - lb + 1, 0),
 		   which could overflow for some cases of empty arrays, e.g.
 		   when lb == index_type'first.  We now compute the length as
-		   (hb < lb) ? 0 : hb - lb + 1, which would only overflow in
+		   (hb >= lb) ? hb - lb + 1 : 0, which would only overflow in
 		   much rarer cases, for extremely large arrays we expect
 		   never to encounter in practice.  In addition, the former
 		   computation required the use of potentially constraining
-		   signed arithmetic while the latter doesn't.  Note that the
-		   comparison must be done in the original index base type,
-		   otherwise the conversion of either bound to gnu_compute_type
-		   may overflow.  */
-		
-		tree gnu_compute_type = get_base_type (gnu_result_type);
-
-		tree index_type
-		  = TYPE_INDEX_TYPE (TYPE_DOMAIN (gnu_type));
-		tree lb
-		  = convert (gnu_compute_type, TYPE_MIN_VALUE (index_type));
-		tree hb
-		  = convert (gnu_compute_type, TYPE_MAX_VALUE (index_type));
-		
+		   signed arithmetic while the latter doesn't.  Note that
+		   the comparison must be done in the original index type,
+		   to avoid any overflow during the conversion.  */
+		tree comp_type = get_base_type (gnu_result_type);
+		tree index_type = TYPE_INDEX_TYPE (TYPE_DOMAIN (gnu_type));
+		tree lb = TYPE_MIN_VALUE (index_type);
+		tree hb = TYPE_MAX_VALUE (index_type);
 		gnu_result
-		  = build3
-		    (COND_EXPR, gnu_compute_type,
-		     build_binary_op (LT_EXPR, get_base_type (index_type),
-				      TYPE_MAX_VALUE (index_type),
-				      TYPE_MIN_VALUE (index_type)),
-		     convert (gnu_compute_type, integer_zero_node),
-		     build_binary_op
-		     (PLUS_EXPR, gnu_compute_type,
-		      build_binary_op (MINUS_EXPR, gnu_compute_type, hb, lb),
-		      convert (gnu_compute_type, integer_one_node)));
+		  = build_binary_op (PLUS_EXPR, comp_type,
+				     build_binary_op (MINUS_EXPR,
+						      comp_type,
+						      convert (comp_type, hb),
+						      convert (comp_type, lb)),
+				     convert (comp_type, integer_one_node));
+		gnu_result
+		  = build_cond_expr (comp_type,
+				     build_binary_op (GE_EXPR,
+						      integer_type_node,
+						      hb, lb),
+				     gnu_result,
+				     convert (comp_type, integer_zero_node));
 	      }
 	  }
 
 	/* If this has a PLACEHOLDER_EXPR, qualify it by the object we are
 	   handling.  Note that these attributes could not have been used on
 	   an unconstrained array type.  */
-	gnu_result = SUBSTITUTE_PLACEHOLDER_IN_EXPR (gnu_result,
-						     gnu_prefix);
+	gnu_result = SUBSTITUTE_PLACEHOLDER_IN_EXPR (gnu_result, gnu_prefix);
 
 	/* Cache the expression we have just computed.  Since we want to do it
 	   at runtime, we force the use of a SAVE_EXPR and let the gimplifier