- // MIR for `undef_union_as_integer` before GVN
+ // MIR for `undef_union_as_integer` after GVN
  
  fn undef_union_as_integer() -> u32 {
      let mut _0: u32;
      let mut _1: undef_union_as_integer::Union32;
      let mut _2: ();
  
      bb0: {
          StorageLive(_1);
          StorageLive(_2);
-         _2 = ();
+         _2 = const ();
          _1 = Union32 { value: move _2 };
          StorageDead(_2);
          _0 = move _1 as u32 (Transmute);
          StorageDead(_1);
          return;
      }
  }