[Ada] Fix ICE on renaming of downcast of dereference

[Ada] Fix ICE on renaming of downcast of dereference

[Eric Botcazou]

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This is a regression present on the mainline: the compiler aborts on the 
renaming of a type conversion of the dereference of an access value, if the 
renaming is declared at library level and used in a subprogram.

Fixed thusly, tested on x86_64-suse-linux, applied on the mainline.


2016-03-07  Eric Botcazou  <ebotcazou@adacore.com>

	* gcc-interface/decl.c (gnat_to_gnu_entity) <E_Variable>: Always mark
	the expression of a renaming manually in case #3.


2016-03-07  Eric Botcazou  <ebotcazou@adacore.com>

	* gnat.dg/renaming9.ad[sb]: New testcase.

-- 
Eric Botcazou

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Index: gcc-interface/decl.c
===================================================================
--- gcc-interface/decl.c	(revision 233957)
+++ gcc-interface/decl.c	(working copy)
@@ -1058,12 +1058,10 @@ gnat_to_gnu_entity (Entity_Id gnat_entit
 		  = elaborate_reference (gnu_expr, gnat_entity, definition,
 					 &init);
 
-		/* If we are not defining the entity, the expression will not
-		   be attached through DECL_INITIAL so it needs to be marked
-		   manually because it will likely be shared.  Likewise for a
-		   dereference as it will be folded by the ADDR_EXPR below.  */
-		if ((!definition || TREE_CODE (renamed_obj) == INDIRECT_REF)
-		    && global_bindings_p ())
+		/* The expression needs to be marked manually because it will
+		   likely be shared, even for a definition since the ADDR_EXPR
+		   built below can cause the first few nodes to be folded.  */
+		if (global_bindings_p ())
 		  MARK_VISITED (renamed_obj);
 
 		if (type_annotate_only

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-- { dg-do compile }

package body Renaming9 is

  procedure Proc is
  begin
    Obj.I := 0;
  end;

begin
  Obj.I := 0;
end Renaming9;

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package Renaming9 is

  pragma Elaborate_Body;

  type Object is tagged null record;

  type Pointer is access all Object'Class;

  type Derived is new Object with record
     I : Integer;
  end record;

  Ptr : Pointer := new Derived;
  Obj : Derived renames Derived (Ptr.all);

end Renaming9;