- // MIR for `opt4` before InstSimplify
+ // MIR for `opt4` after InstSimplify
  
  fn opt4(_1: bool) -> u32 {
      debug x => _1;
      let mut _0: u32;
      let mut _2: bool;
      let mut _3: bool;
  
      bb0: {
          StorageLive(_2);
          StorageLive(_3);
          _3 = _1;
-         _2 = Eq(const false, move _3);
+         _2 = Not(move _3);
          switchInt(move _2) -> [0: bb2, otherwise: bb1];
      }
  
      bb1: {
          StorageDead(_3);
          _0 = const 0_u32;
          goto -> bb3;
      }
  
      bb2: {
          StorageDead(_3);
          _0 = const 1_u32;
          goto -> bb3;
      }
  
      bb3: {
          StorageDead(_2);
          return;
      }
  }