gcc/testsuite/gnat.dg/unchecked_union1.adb

   1 -- { dg-do run }
   2
   3 procedure Unchecked_Union1 is
   4
   5   type Bit is (Zero, One);
   6
   7   type U (X : Bit := Zero) is record
   8     case X is
   9       when Zero => I: Integer;
  10       when One => F : Float;
  11     end case;
  12   end record;
  13   for U use record
  14     I at 0 range  0 .. 31;
  15     F at 0 range  0 .. 31;
  16   end record;
  17   pragma Unchecked_Union(U);
  18
  19 begin
  20   if U'Object_Size /= 32 then
  21     raise Program_Error;
  22   end if;
  23 end;