- // MIR for `loop_deref_mut` before GVN
+ // MIR for `loop_deref_mut` after GVN
  
  fn loop_deref_mut(_1: &mut Value) -> Value {
      debug val => _1;
      let mut _0: Value;
      let _2: &Value;
      let _3: &Value;
      let mut _4: &Value;
      let mut _6: !;
      let mut _8: isize;
      let mut _9: !;
      let mut _10: ();
      let mut _12: i32;
      let _13: ();
      let mut _14: bool;
      let mut _15: !;
      let mut _16: Value;
      scope 1 {
          debug val_alias => _3;
          let mut _5: bool;
          scope 2 {
              debug stop => _5;
              let _7: i32;
              scope 3 {
                  debug v => _7;
                  let _11: Value;
                  scope 4 {
                      debug v => _11;
                  }
              }
          }
      }
  
      bb0: {
          StorageLive(_4);
          _4 = &(*_1);
          _3 = get::<Value>(copy _4) -> [return: bb1, unwind unreachable];
      }
  
      bb1: {
          StorageDead(_4);
          StorageLive(_5);
          _5 = const false;
          _8 = discriminant((*_3));
          switchInt(move _8) -> [0: bb3, otherwise: bb2];
      }
  
      bb2: {
          unreachable;
      }
  
      bb3: {
-         StorageLive(_7);
+         nop;
          _7 = copy (((*_3) as V0).0: i32);
          goto -> bb4;
      }
  
      bb4: {
          StorageLive(_11);
          StorageLive(_12);
          _12 = copy _7;
-         _11 = Value::V0(move _12);
+         _11 = Value::V0(copy _7);
          StorageDead(_12);
          StorageLive(_14);
          _14 = copy _5;
          switchInt(move _14) -> [0: bb6, otherwise: bb5];
      }
  
      bb5: {
          _0 = move _11;
          StorageDead(_14);
          StorageDead(_11);
-         StorageDead(_7);
+         nop;
          StorageDead(_5);
          return;
      }
  
      bb6: {
          StorageDead(_14);
          _5 = const true;
          StorageLive(_16);
-         _16 = Value::V1;
-         (*_1) = move _16;
+         _16 = const Value::V1;
+         (*_1) = const Value::V1;
          StorageDead(_16);
          StorageDead(_11);
          goto -> bb4;
      }
  }
+ 
+ ALLOC0 (size: 8, align: 4) { .. }