decl.c (gnat_to_gnu_entity): For a subtype with discriminant constraints...

	2007-09-12  Olivier Hainque  <hainque@adacore.com>

	ada/
	* decl.c (gnat_to_gnu_entity) <E_Record_Subtype>: For a subtype
	with discriminant constraints, generalize the code for BIT_FIELDs
	to PACKED fields of constant size and propagate DECL_PACKED.

	testsuite/
	* gnat.dg/packed_subtype.adb: New test.

From-SVN: r128425

gcc/ada/ChangeLog

+2007-09-12  Olivier Hainque  <hainque@adacore.com>
+
+	* decl.c (gnat_to_gnu_entity) <E_Record_Subtype>: For a subtype
+	with discriminant constraints, generalize the code for BIT_FIELDs
+	to PACKED fields of constant size and propagate DECL_PACKED.
+
 2007-09-11  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* decl.c (array_type_has_nonaliased_component): New predicate.

gcc/ada/decl.c

@@ -2762,9 +2762,14 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 			gnu_field_type = TREE_TYPE (gnu_old_field);
 		      }
 
-		    /* If this was a bitfield, get the size from the old field.
-		       Also ensure the type can be placed into a bitfield.  */
-		    else if (DECL_BIT_FIELD (gnu_old_field))
+		    /* If the old field was packed and of constant size, we
+		       have to get the old size here, as it might differ from
+		       what the Etype conveys and the latter might overlap
+		       onto the following field.  Try to arrange the type for
+		       possible better packing along the way.  */
+		    else if (DECL_PACKED (gnu_old_field)
+			     && TREE_CODE (DECL_SIZE (gnu_old_field))
+			        == INTEGER_CST)
 		      {
 			gnu_size = DECL_SIZE (gnu_old_field);
 			if (TYPE_MODE (gnu_field_type) == BLKmode
@@ -2789,7 +2794,7 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 		    gnu_field
 		      = create_field_decl
 			(DECL_NAME (gnu_old_field), gnu_field_type, gnu_type,
-			 0, gnu_size, gnu_new_pos,
+			 DECL_PACKED (gnu_old_field), gnu_size, gnu_new_pos,
 			 !DECL_NONADDRESSABLE_P (gnu_old_field));
 
 		    if (!TREE_CONSTANT (gnu_pos))

gcc/testsuite/ChangeLog

+2007-09-12  Olivier Hainque  <hainque@adacore.com>
+
+	* gnat.dg/packed_subtype.adb: New test.
+
 2007-09-12  Tobias Burnus  <burnus@net-b.de>
 
 	PR fortran/33297

gcc/testsuite/gnat.dg/packed_subtype.adb

+-- { dg-do run }
+
+procedure Packed_Subtype is
+
+   subtype Ubyte is Integer range 0 .. 255;
+   type Packet (Id : Ubyte) is record
+      A, B : Ubyte;
+   end record;
+   pragma Pack (Packet);
+
+   subtype My_Packet is Packet (Id => 1);
+
+   MP : My_Packet;
+begin
+   MP.A := 1;
+   MP.B := 2;
+
+   if MP.A /= 1 or else MP.B /= 2 then
+      raise Program_Error;
+   end if;
+end;
+
+
+