Closed
Description
Environment
- Qiskit version:
2.0.0.dev0+5de0232
What is happening?
In #11212 we decided to "stop using CXCancellation as part of the preset pass managers as it's been superseded by InverseCancellation". However, CXCancellation runs inside flow controlled blocks but InverseCancellation does not.
How can we reproduce the issue?
- Create a circuit with control flow:
from qiskit import QuantumCircuit
inner = QuantumCircuit(2,1)
inner.cx(0, 1)
inner.cx(0, 1)
qc = QuantumCircuit(2, 1)
qc.cx(0, 1)
qc.cx(0, 1)
qc.if_else((0, True), inner.copy(), inner.copy(), range(2), [0])
qc.draw()- Run
InverseCancellationon it
from qiskit.transpiler.passes import InverseCancellation
from qiskit.circuit.library.standard_gates import CXGate
InverseCancellation([CXGate()])(qc).draw()Notice that the CX outside got cancelled, but not those inside.
What should happen?
It should be like CXCancellation
from qiskit.transpiler.passes import CXCancellation
CXCancellation()(qc).draw()Any suggestions?
Apply InverseCancellation recursively inside the code blocks.
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