- // MIR for `main` before GVN
+ // MIR for `main` after GVN
  
  fn main() -> () {
      let mut _0: ();
      let _1: i32;
      let mut _2: i32;
      let mut _3: std::option::Option<bool>;
      let mut _4: isize;
      scope 1 {
          debug x => _1;
      }
      scope 2 {
      }
  
      bb0: {
          StorageLive(_1);
          StorageLive(_2);
          StorageLive(_3);
-         _3 = Option::<bool>::Some(const true);
-         _4 = discriminant(_3);
-         switchInt(move _4) -> [1: bb1, otherwise: bb3];
+         _3 = const Option::<bool>::Some(true);
+         _4 = const 1_isize;
+         switchInt(const 1_isize) -> [1: bb1, otherwise: bb3];
      }
  
      bb1: {
-         switchInt(copy ((_3 as Some).0: bool)) -> [0: bb3, otherwise: bb2];
+         switchInt(const true) -> [0: bb3, otherwise: bb2];
      }
  
      bb2: {
          _2 = const 42_i32;
          goto -> bb4;
      }
  
      bb3: {
          _2 = const 10_i32;
          goto -> bb4;
      }
  
      bb4: {
          _1 = Add(move _2, const 0_i32);
          StorageDead(_2);
          StorageDead(_3);
          _0 = const ();
          StorageDead(_1);
          return;
      }
  }