Support target and basis gates in Unroll3qOrMore transpiler pass

qiskit/transpiler/passes/basis/unroll_3q_or_more.py

@@ -20,6 +20,27 @@
 class Unroll3qOrMore(TransformationPass):
     """Recursively expands 3q+ gates until the circuit only contains 2q or 1q gates."""
 
+    def __init__(self, target=None, basis_gates=None):
+        """Initialize the Unroll3qOrMore pass
+
+        Args:
+            target (Target): The target object reprsenting the compilation
+                target. If specified any multiqubit instructions in the
+                circuit when the pass is run that are supported by the target
+                device will be left in place. If both this and ``basis_gates``
+                are specified only the target will be checked.
+            basis_gates (list): A list of basis gate names that the target
+                device supports. If specified any gate names in the circuit
+                which are present in this list will not be unrolled. If both
+                this and ``target`` are specified only the target will be used
+                for checking which gates are supported.
+        """
+        super().__init__()
+        self.target = target
+        self.basis_gates = None
+        if basis_gates is not None:
+            self.basis_gates = set(basis_gates)
+
     def run(self, dag):
         """Run the Unroll3qOrMore pass on `dag`.
 
@@ -33,6 +54,15 @@ def run(self, dag):
         for node in dag.multi_qubit_ops():
             if dag.has_calibration_for(node):
                 continue
+            if self.target is not None:
+                # Treat target instructions as global since this pass can be run
+                # prior to layout and routing we don't have phsyical qubits from
+                # the circuit yet
+                if node.name in self.target:
+                    continue
+            elif self.basis_gates is not None and node.name in self.basis_gates:
+                continue
+
             # TODO: allow choosing other possible decompositions
             rule = node.op.definition.data
             if not rule:

qiskit/transpiler/preset_passmanagers/level0.py

@@ -108,7 +108,7 @@ def level_0_pass_manager(pass_manager_config: PassManagerConfig) -> PassManager:
             plugin_config=unitary_synthesis_plugin_config,
             target=target,
         ),
-        Unroll3qOrMore(),
+        Unroll3qOrMore(target=target, basis_gates=basis_gates),
     ]
 
     # 2. Choose an initial layout if not set by user (default: trivial layout)
@@ -190,7 +190,7 @@ def _swap_condition(property_set):
                 plugin_config=unitary_synthesis_plugin_config,
                 target=target,
             ),
-            Unroll3qOrMore(),
+            Unroll3qOrMore(target=target, basis_gates=basis_gates),
             Collect2qBlocks(),
             Collect1qRuns(),
             ConsolidateBlocks(basis_gates=basis_gates, target=target),

qiskit/transpiler/preset_passmanagers/level1.py

@@ -173,7 +173,7 @@ def _vf2_match_not_found(property_set):
             plugin_config=unitary_synthesis_plugin_config,
             target=target,
         ),
-        Unroll3qOrMore(),
+        Unroll3qOrMore(target=target, basis_gates=basis_gates),
     ]
 
     # 3. Use a better layout on densely connected qubits, if circuit needs swaps
@@ -253,7 +253,7 @@ def _swap_condition(property_set):
                 min_qubits=3,
                 target=target,
             ),
-            Unroll3qOrMore(),
+            Unroll3qOrMore(target=target, basis_gates=basis_gates),
             Collect2qBlocks(),
             ConsolidateBlocks(basis_gates=basis_gates, target=target),
             UnitarySynthesis(

qiskit/transpiler/preset_passmanagers/level2.py

@@ -122,7 +122,7 @@ def level_2_pass_manager(pass_manager_config: PassManagerConfig) -> PassManager:
             plugin_config=unitary_synthesis_plugin_config,
             target=target,
         ),
-        Unroll3qOrMore(),
+        Unroll3qOrMore(target=target, basis_gates=basis_gates),
     ]
 
     # 2. Search for a perfect layout, or choose a dense layout, if no layout given
@@ -238,7 +238,7 @@ def _swap_condition(property_set):
                 min_qubits=3,
                 target=target,
             ),
-            Unroll3qOrMore(),
+            Unroll3qOrMore(target=target, basis_gates=basis_gates),
             Collect2qBlocks(),
             ConsolidateBlocks(basis_gates=basis_gates, target=target),
             UnitarySynthesis(

qiskit/transpiler/preset_passmanagers/level3.py

@@ -125,7 +125,7 @@ def level_3_pass_manager(pass_manager_config: PassManagerConfig) -> PassManager:
             min_qubits=3,
             target=target,
         ),
-        Unroll3qOrMore(),
+        Unroll3qOrMore(target=target, basis_gates=basis_gates),
     ]
 
     # 2. Layout on good qubits if calibration info available, otherwise on dense links
@@ -236,7 +236,7 @@ def _swap_condition(property_set):
                 min_qubits=3,
                 target=target,
             ),
-            Unroll3qOrMore(),
+            Unroll3qOrMore(target=target, basis_gates=basis_gates),
             Collect2qBlocks(),
             ConsolidateBlocks(basis_gates=basis_gates, target=target),
             UnitarySynthesis(

releasenotes/notes/unroll3q-target-bf57cc4365808862.yaml

@@ -0,0 +1,10 @@
+---
+features:
+  - |
+    The constructor for the :class:`~.Unroll3qOrMore` transpiler pass has
+    two new optional keyword arguments, ``target`` and ``basis`` gates. These
+    options enable you to specify the :class:`~.Target` or supported basis
+    gates respectively to describe the target backend. If any of the operations
+    in the circuit are in the ``target`` or ``basis_gates`` those will not
+    be unrolled by the pass as the target device has native support for the
+    operation.

test/python/transpiler/test_unroll_3q_or_more.py

@@ -12,13 +12,16 @@
 
 """Test the Unroll3qOrMore pass"""
 import numpy as np
+
 from qiskit import QuantumRegister, ClassicalRegister, QuantumCircuit
+from qiskit.circuit.library import CCXGate, RCCXGate
 from qiskit.transpiler.passes import Unroll3qOrMore
 from qiskit.converters import circuit_to_dag, dag_to_circuit
 from qiskit.quantum_info.operators import Operator
 from qiskit.quantum_info.random import random_unitary
 from qiskit.test import QiskitTestCase
 from qiskit.extensions import UnitaryGate
+from qiskit.transpiler import Target
 
 
 class TestUnroll3qOrMore(QiskitTestCase):
@@ -91,3 +94,39 @@ def test_identity(self):
         after_dag = pass_.run(dag)
         after_circ = dag_to_circuit(after_dag)
         self.assertTrue(Operator(circuit).equiv(Operator(after_circ)))
+
+    def test_target(self):
+        """Test target is respected by the unroll 3q or more pass."""
+        target = Target(num_qubits=3)
+        target.add_instruction(CCXGate())
+        qc = QuantumCircuit(3)
+        qc.ccx(0, 1, 2)
+        qc.append(RCCXGate(), [0, 1, 2])
+        unroll_pass = Unroll3qOrMore(target=target)
+        res = unroll_pass(qc)
+        self.assertIn('ccx', res.count_ops())
+        self.assertNotIn('rccx', res.count_ops())
+
+    def test_basis_gates(self):
+        """Test basis_gates are respected by the unroll 3q or more pass."""
+        basis_gates = ["rccx"]
+        qc = QuantumCircuit(3)
+        qc.ccx(0, 1, 2)
+        qc.append(RCCXGate(), [0, 1, 2])
+        unroll_pass = Unroll3qOrMore(basis_gates=basis_gates)
+        res = unroll_pass(qc)
+        self.assertNotIn('ccx', res.count_ops())
+        self.assertIn('rccx', res.count_ops())
+
+    def test_target_over_basis_gates(self):
+        """Test target is respected over basis_gates  by the unroll 3q or more pass."""
+        target = Target(num_qubits=3)
+        basis_gates = ['rccx']
+        target.add_instruction(CCXGate())
+        qc = QuantumCircuit(3)
+        qc.ccx(0, 1, 2)
+        qc.append(RCCXGate(), [0, 1, 2])
+        unroll_pass = Unroll3qOrMore(target=target, basis_gates=basis_gates)
+        res = unroll_pass(qc)
+        self.assertIn('ccx', res.count_ops())
+        self.assertNotIn('rccx', res.count_ops())