decl.c (gnat_to_gnu_entity): When discriminants affect the shape of the subtype...

	* gcc-interface/decl.c (gnat_to_gnu_entity) <E_Record_Subtype>: When
	discriminants affect the shape of the subtype, retrieve the GCC type
	directly from the original field if the GNAT types for the field and
	the original field are the same.

From-SVN: r147732

gcc/ada/ChangeLog

+2009-05-20  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gcc-interface/decl.c (gnat_to_gnu_entity) <E_Record_Subtype>: When
+	discriminants affect the shape of the subtype, retrieve the GCC type
+	directly from the original field if the GNAT types for the field and
+	the original field are the same.
+
 2009-05-15  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* gcc-interface/ada-tree.h (TYPE_GCC_MIN_VALUE, TYPE_GCC_MAX_VALUE):

gcc/ada/gcc-interface/decl.c

@@ -3124,21 +3124,27 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 			|| !Is_Tagged_Type (gnat_base_type)))
 		  {
 		    tree gnu_old_field
-		      = gnat_to_gnu_field_decl (Original_Record_Component
-						(gnat_field));
+		      = gnat_to_gnu_field_decl
+			(Original_Record_Component (gnat_field));
 		    tree gnu_offset
-		      = TREE_VALUE (purpose_member (gnu_old_field,
-						    gnu_pos_list));
+		      = TREE_VALUE
+			(purpose_member (gnu_old_field, gnu_pos_list));
 		    tree gnu_pos = TREE_PURPOSE (gnu_offset);
 		    tree gnu_bitpos = TREE_VALUE (TREE_VALUE (gnu_offset));
-		    tree gnu_field_type
-		      = gnat_to_gnu_type (Etype (gnat_field));
-		    tree gnu_size = TYPE_SIZE (gnu_field_type);
-		    tree gnu_new_pos = NULL_TREE;
+		    tree gnu_field, gnu_field_type, gnu_size, gnu_new_pos;
 		    unsigned int offset_align
-		      = tree_low_cst (TREE_PURPOSE (TREE_VALUE (gnu_offset)),
-				      1);
-		    tree gnu_field;
+		      = tree_low_cst
+			(TREE_PURPOSE (TREE_VALUE (gnu_offset)), 1);
+
+		    /* If the type is the same, retrieve the GCC type from the
+		       old field to take into account possible adjustments.  */
+		    if (Etype (gnat_field)
+			== Etype (Original_Record_Component (gnat_field)))
+		      gnu_field_type = TREE_TYPE (gnu_old_field);
+		    else
+		      gnu_field_type = gnat_to_gnu_type (Etype (gnat_field));
+
+		    gnu_size = TYPE_SIZE (gnu_field_type);
 
 		    /* If there was a component clause, the field types must be
 		       the same for the type and subtype, so copy the data from
@@ -3197,6 +3203,8 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 						 TYPE_SIZE (gnu_type)))
 			  continue;
 		      }
+		    else
+		      gnu_new_pos = NULL_TREE;
 
 		    gnu_field
 		      = create_field_decl