re PR ada/48844 (ICE on assignment of aggregate with discriminated record type)

	PR ada/48844
	* gcc-interface/gigi.h (get_variant_part): Declare.
	* gcc-interface/decl.c (get_variant_part): Make global.
	* gcc-interface/utils2.c (find_common_type): Do not return T1 if the
	types have the same constant size, are record types and T1 has a
	variant part while T2 doesn't.

From-SVN: r173442

gcc/ada/ChangeLog

 2011-05-05  Eric Botcazou  <ebotcazou@adacore.com>
 
+	PR ada/48844
+	* gcc-interface/gigi.h (get_variant_part): Declare.
+	* gcc-interface/decl.c (get_variant_part): Make global.
+	* gcc-interface/utils2.c (find_common_type): Do not return T1 if the
+	types have the same constant size, are record types and T1 has a
+	variant part while T2 doesn't.
+
+2011-05-05  Eric Botcazou  <ebotcazou@adacore.com>
+
 	* gcc-interface/utils.c (begin_subprog_body): Do not call
 	get_pending_sizes.
 	(end_subprog_body): Likewise.

gcc/ada/gcc-interface/decl.c

@@ -177,7 +177,6 @@ static void check_ok_for_atomic (tree, Entity_Id, bool);
 static tree create_field_decl_from (tree, tree, tree, tree, tree,
 				    VEC(subst_pair,heap) *);
 static tree get_rep_part (tree);
-static tree get_variant_part (tree);
 static tree create_variant_part_from (tree, VEC(variant_desc,heap) *, tree,
 				      tree, VEC(subst_pair,heap) *);
 static void copy_and_substitute_in_size (tree, tree, VEC(subst_pair,heap) *);
@@ -8509,7 +8508,7 @@ get_rep_part (tree record_type)
 
 /* Return the variant part of RECORD_TYPE, if any.  Otherwise return NULL.  */
 
-static tree
+tree
 get_variant_part (tree record_type)
 {
   tree field;

gcc/ada/gcc-interface/gigi.h

@@ -150,6 +150,9 @@ extern tree choices_to_gnu (tree operand, Node_Id choices);
 extern void annotate_object (Entity_Id gnat_entity, tree gnu_type, tree size,
 			     bool by_ref, bool by_double_ref);
 
+/* Return the variant part of RECORD_TYPE, if any.  Otherwise return NULL.  */
+extern tree get_variant_part (tree record_type);
+
 /* Given a type T, a FIELD_DECL F, and a replacement value R, return a new
    type with all size expressions that contain F updated by replacing F
    with R.  If F is NULL_TREE, always make a new RECORD_TYPE, even if

gcc/ada/gcc-interface/utils2.c

@@ -193,15 +193,21 @@ find_common_type (tree t1, tree t2)
      calling into build_binary_op), some others are really expected and we
      have to be careful.  */
 
-  /* We must prevent writing more than what the target may hold if this is for
+  /* We must avoid writing more than what the target can hold if this is for
      an assignment and the case of tagged types is handled in build_binary_op
-     so use the lhs type if it is known to be smaller, or of constant size and
-     the rhs type is not, whatever the modes.  We also force t1 in case of
+     so we use the lhs type if it is known to be smaller or of constant size
+     and the rhs type is not, whatever the modes.  We also force t1 in case of
      constant size equality to minimize occurrences of view conversions on the
-     lhs of assignments.  */
+     lhs of an assignment, except for the case of record types with a variant
+     part on the lhs but not on the rhs to make the conversion simpler.  */
   if (TREE_CONSTANT (TYPE_SIZE (t1))
       && (!TREE_CONSTANT (TYPE_SIZE (t2))
-          || !tree_int_cst_lt (TYPE_SIZE (t2), TYPE_SIZE (t1))))
+	  || tree_int_cst_lt (TYPE_SIZE (t1), TYPE_SIZE (t2))
+	  || (TYPE_SIZE (t1) == TYPE_SIZE (t2)
+	      && !(TREE_CODE (t1) == RECORD_TYPE
+		   && TREE_CODE (t2) == RECORD_TYPE
+		   && get_variant_part (t1) != NULL_TREE
+		   && get_variant_part (t2) == NULL_TREE))))
     return t1;
 
   /* Otherwise, if the lhs type is non-BLKmode, use it.  Note that we know

gcc/testsuite/ChangeLog

+2011-05-05  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gnat.dg/discr29.ad[sb]: New test.
+	* gnat.dg/discr30.adb: Likewise.
+
 2011-05-05  Julian Brown  <julian@codesourcery.com>
 
 	* gcc.target/arm/neon-vset_lanes8.c: New test.

gcc/testsuite/gnat.dg/discr29.adb

+package body Discr29 is
+
+   procedure Proc (R : out Rec3) is
+   begin
+      R := (False, Tmp);
+   end;
+
+end Discr29;

gcc/testsuite/gnat.dg/discr29.ads

+-- { dg-do compile }
+
+package Discr29 is
+
+   type Rec1 is record
+      I1 : Integer;
+      I2 : Integer;
+      I3 : Integer;
+   end record;
+
+   type Rec2 is tagged record
+      I1 : Integer;
+      I2 : Integer;
+   end record;
+
+   type Rec3 (D : Boolean) is record
+      case D is
+         when True =>  A : Rec1;
+         when False => B : Rec2;
+      end case;
+   end record;
+
+   procedure Proc (R : out Rec3);
+
+   Tmp : Rec2;
+
+end Discr29;

gcc/testsuite/gnat.dg/discr30.adb

+-- PR ada/48844
+-- Reported by Georg Bauhaus <bauhaus@futureapps.de> */
+
+-- { dg-do compile }
+
+procedure Discr30 is
+
+   generic
+     type Source is private;
+     type Target is private;
+   function Conversion (S : Source) return Target;
+
+   function Conversion (S : Source) return Target is
+      type Source_Wrapper is tagged record
+         S : Source;
+      end record;
+      type Target_Wrapper is tagged record
+         T : Target;
+      end record;
+
+      type Selector is (Source_Field, Target_Field);
+      type Magic (Sel : Selector := Target_Field) is record
+         case Sel is
+            when Source_Field => S : Source_Wrapper;
+            when Target_Field => T : Target_Wrapper;
+         end case;
+      end record;
+
+      M : Magic;
+
+      function Convert (T : Target_Wrapper) return Target is
+      begin
+         M := (Sel => Source_Field, S => (S => S));
+         return T.T;
+      end Convert;
+
+   begin
+      return Convert (M.T);
+   end Conversion;
+
+   type Integer_Access is access all Integer;
+
+   I : aliased Integer;
+   I_Access : Integer_Access := I'Access;
+
+   function Convert is new Conversion (Integer_Access, Integer);
+
+begin
+   I := Convert (I_Access);
+end;