gcc/testsuite/gnat.dg/pack12.adb

-- { dg-do run }

procedure Pack12 is

  type U16 is mod 2 ** 16;

  type Key is record
    Value : U16;
    Valid : Boolean;
  end record;

  type Key_Buffer is record
    Current, Latch : Key;
  end record;

  type Block is record
    Keys  : Key_Buffer;
    Stamp : U16;
  end record;
  pragma Pack (Block);

  My_Block : Block;
  My_Stamp : constant := 16#1234#;

begin
  My_Block.Stamp := My_Stamp;
  My_Block.Keys.Latch := My_Block.Keys.Current;
  if My_Block.Stamp /= My_Stamp then
    raise Program_Error;
  end if;
end;