[Ada] Lingering loop for ignored Ghost assignment

[Ada] Lingering loop for ignored Ghost assignment

The following patch ensures that loops generated for aggregates as part
of ignored Ghost assignments are correctly eliminated from the generated
code.

------------
-- Source --
------------

--  pack.ads

package Pack is
   type addr4k is new Integer range 0 .. 100 with Size => 32;

   type Four_KB_Page_Property is record
      Is_Scrubbed : Boolean := False;
   end record with Ghost;

   type Four_KB_Page_Array is
     array (addr4k range <>) of Four_KB_Page_Property with Ghost;

   type Base_Memory is tagged record
      Four_KB_Pages : Four_KB_Page_Array (addr4k) :=
                        (others => (Is_Scrubbed => False));
   end record with Ghost;

   subtype Memory is Base_Memory with Ghost;
   Global_Memory : Memory with Ghost;

   procedure Assign;
end Pack;

--  pack.adb

package body Pack is
   procedure Assign is
   begin
      Global_Memory.Four_KB_Pages := (others => (Is_Scrubbed => True));
   end Assign;
end Pack;

----------------------------
-- Compilation and output --
----------------------------

$ gcc -c -gnatDG pack.adb
$ grep -c "loop" pack.adb.dg
0

2018-11-14  Hristian Kirtchev  <kirtchev@adacore.com>

gcc/ada/

	* exp_ch4.adb (Expand_Concatenate): Use the proper routine to
	set the need for debug info.
	* exp_dbug.adb (Build_Subprogram_Instance_Renamings): Use the
	proper routine to set the need for debug info.
	* exp_prag.adb (Expand_Pragma_Initial_Condition): Use the proper
	routine to set the need for debug info.
	* exp_util.adb (Build_DIC_Procedure_Declaration): Use the proper
	routine to set the need for debug info.
	(Build_Invariant_Procedure_Declaration): Use the proper routine
	to set the need for debug info.
	* ghost.adb (Record_Ignored_Ghost_Node): Add statements as a
	whole class to the list of top level ignored Ghost nodes.
	* sem_util.adb (Set_Debug_Info_Needed): Do not generate debug
	info for an ignored Ghost entity.

From-SVN: r266111