diff --git a/qlasskit/boolopt/bool_optimizer.py b/qlasskit/boolopt/bool_optimizer.py
index 52c86db4..516b4ebf 100644
--- a/qlasskit/boolopt/bool_optimizer.py
+++ b/qlasskit/boolopt/bool_optimizer.py
@@ -93,3 +93,17 @@ def apply(self, exps):
         transform_or2and(),
     ]
 )
+
+
+bestWorkingOptimizerDebug = BoolOptimizerProfile(
+    [
+        print_step("before"),
+        merge_expressions,
+        apply_cse,
+        remove_ITE(),
+        remove_Implies(),
+        transform_or2xor(),
+        transform_or2and(),
+        print_step("after"),
+    ]
+)
diff --git a/qlasskit/qcircuit/cnotsim.py b/qlasskit/qcircuit/cnotsim.py
index 4d2c08d6..ef94f63e 100644
--- a/qlasskit/qcircuit/cnotsim.py
+++ b/qlasskit/qcircuit/cnotsim.py
@@ -55,10 +55,7 @@ def simulate(  # noqa: C901
             elif isinstance(g, CCX):
                 if qubits[w[0]] and qubits[w[1]]:
                     qubits[w[2]] = not qubits[w[2]]
-            elif isinstance(g, MCX):
-                if all([qubits[x] for x in w[0:-1]]):
-                    qubits[w[-1]] = not qubits[w[-1]]
-            elif isinstance(g, MCtrl) and isinstance(g.gate, X):
+            elif isinstance(g, MCX) or (isinstance(g, MCtrl) and isinstance(g.gate, X)):
                 if all([qubits[x] for x in w[0:-1]]):
                     qubits[w[-1]] = not qubits[w[-1]]
             else:
diff --git a/test/test_qlassf.py b/test/test_qlassf.py
index 19c4720a..a5c81068 100644
--- a/test/test_qlassf.py
+++ b/test/test_qlassf.py
@@ -17,6 +17,7 @@
 from parameterized import parameterized_class
 
 from qlasskit import Qint, Qint2, Qint4, Qint12, QlassF, exceptions, qlassf
+from qlasskit.boolopt.bool_optimizer import bestWorkingOptimizerDebug
 
 from . import utils
 from .utils import COMPILATION_ENABLED, ENABLED_COMPILERS, compute_and_compare_results
@@ -28,6 +29,16 @@ def test_decorator(self):
         self.assertTrue(isinstance(c, QlassF))
 
 
+class TestQlassfOptimizerSelection(unittest.TestCase):
+    def test_debug_optimizer(self):
+        qf = qlassf(
+            "def t(a: bool) -> bool: return a",
+            to_compile=COMPILATION_ENABLED,
+            bool_optimizer=bestWorkingOptimizerDebug,
+        )
+        compute_and_compare_results(self, qf)
+
+
 @parameterized_class(("compiler"), ENABLED_COMPILERS)
 class TestQlassfCustomTypes(unittest.TestCase):
     def test_custom_qint3(self):