Environment

• Qiskit version: 1.2.4
• Python version: 3.11.3
• Operating system: Ubuntu Linux

What is happening?

Why does qiskit.transpile() function with optimization level 3 not remove a cp (controlled phase) gate when its parameter is 0? Since a cp(0) gate is equivalent to an identity operation, it should be optimized away.

How can we reproduce the issue?

import qiskit
import qiskit_aer
circuit = qiskit.QuantumCircuit(2)
circuit.cp(0, 1, 0)
circuit = qiskit.transpile(circuit, qiskit_aer.AerSimulator(), optimization_level=3)
circuit.data

Output:

[CircuitInstruction(operation=Instruction(name='cp', num_qubits=2, num_clbits=0, params=[0.0]), qubits=(Qubit(QuantumRegister(2, 'q'), 1), Qubit(QuantumRegister(2, 'q'), 0)), clbits=())]

What should happen?

The gate should be removed.

Any suggestions?

No response