add label for ccx

Author: Hazarre

qiskit/circuit/quantumcircuit.py

@@ -6284,6 +6284,7 @@ def ccx(
         control_qubit1: QubitSpecifier,
         control_qubit2: QubitSpecifier,
         target_qubit: QubitSpecifier,
+        label: str | None = None,
         ctrl_state: str | int | None = None,
     ) -> InstructionSet:
         r"""Apply :class:`~qiskit.circuit.library.CCXGate`.
@@ -6294,6 +6295,7 @@ def ccx(
             control_qubit1: The qubit(s) used as the first control.
             control_qubit2: The qubit(s) used as the second control.
             target_qubit: The qubit(s) targeted by the gate.
+            label: The string label of the gate in the circuit.
             ctrl_state:
                 The control state in decimal, or as a bitstring (e.g. '1').  Defaults to controlling
                 on the '1' state.
@@ -6307,12 +6309,13 @@ def ccx(
                 StandardGate.CCX,
                 [control_qubit1, control_qubit2, target_qubit],
                 (),
+                label=label,
             )
 
         from .library.standard_gates.x import CCXGate
 
         return self.append(
-            CCXGate(ctrl_state=ctrl_state),
+            CCXGate(label=label, ctrl_state=ctrl_state),
             [control_qubit1, control_qubit2, target_qubit],
             [],
             copy=False,

test/python/circuit/test_controlled_gate.py

@@ -1114,6 +1114,14 @@ def test_ccx_ctrl_state_consistency(self):
         ref_circuit.append(ccx, [qreg[0], qreg[1], qreg[2]])
         self.assertEqual(qc, ref_circuit)
 
+    def test_ccx_label_parameter(self):
+        """To check that labels are forwarded to CCX gates."""
+        qreg = QuantumRegister(3)
+        qc = QuantumCircuit(qreg)
+        qc.ccx(qreg[0], qreg[1], qreg[2], label="my_ccx", ctrl_state=0)
+
+        self.assertEqual(qc.data[0].operation.label, "my_ccx")
+
     @data((4, [0, 1, 2], 3, "010"), (4, [2, 1, 3], 0, 2))
     @unpack
     def test_multi_control_x_ctrl_state_parameter(