- // MIR for `main` before GVN
+ // MIR for `main` after GVN
  
  fn main() -> () {
      let mut _0: ();
      let _1: i32;
      let mut _2: &i32;
      let _3: i32;
      let mut _4: &i32;
      scope 1 {
          debug a => _1;
      }
  
      bb0: {
          StorageLive(_1);
          StorageLive(_2);
          _4 = const main::promoted[0];
          _2 = &(*_4);
-         _1 = copy (*_2);
+         _1 = const 4_i32;
          StorageDead(_2);
          _0 = const ();
          StorageDead(_1);
          return;
      }
  }