- // MIR for `opt4` before InstSimplify
+ // MIR for `opt4` after InstSimplify
  
  fn opt4(_1: bool) -> u32 {
      debug x => _1;                       // in scope 0 at $DIR/bool_compare.rs:+0:9: +0:10
      let mut _0: u32;                     // return place in scope 0 at $DIR/bool_compare.rs:+0:21: +0:24
      let mut _2: bool;                    // in scope 0 at $DIR/bool_compare.rs:+1:8: +1:18
      let mut _3: bool;                    // in scope 0 at $DIR/bool_compare.rs:+1:17: +1:18
  
      bb0: {
          StorageLive(_2);                 // scope 0 at $DIR/bool_compare.rs:+1:8: +1:18
          StorageLive(_3);                 // scope 0 at $DIR/bool_compare.rs:+1:17: +1:18
          _3 = _1;                         // scope 0 at $DIR/bool_compare.rs:+1:17: +1:18
-         _2 = Eq(const false, move _3);   // scope 0 at $DIR/bool_compare.rs:+1:8: +1:18
+         _2 = Not(move _3);               // scope 0 at $DIR/bool_compare.rs:+1:8: +1:18
          StorageDead(_3);                 // scope 0 at $DIR/bool_compare.rs:+1:17: +1:18
          switchInt(move _2) -> [0: bb2, otherwise: bb1]; // scope 0 at $DIR/bool_compare.rs:+1:8: +1:18
      }
  
      bb1: {
          _0 = const 0_u32;                // scope 0 at $DIR/bool_compare.rs:+1:21: +1:22
          goto -> bb3;                     // scope 0 at $DIR/bool_compare.rs:+1:5: +1:35
      }
  
      bb2: {
          _0 = const 1_u32;                // scope 0 at $DIR/bool_compare.rs:+1:32: +1:33
          goto -> bb3;                     // scope 0 at $DIR/bool_compare.rs:+1:5: +1:35
      }
  
      bb3: {
          StorageDead(_2);                 // scope 0 at $DIR/bool_compare.rs:+1:34: +1:35
          return;                          // scope 0 at $DIR/bool_compare.rs:+2:2: +2:2
      }
  }