Avoid Python op creation in BasisTranslator (Qiskit#12705)

This commit updates the BasisTranslator transpiler pass. It builds off
of Qiskit#12692 and Qiskit#12701 to adjust access patterns in the python transpiler
path to avoid eagerly creating a Python space operation object. The goal
of this PR is to mitigate the performance regression introduced by the
extra conversion cost of Qiskit#12459 on the BasisTranslator.

crates/circuit/src/dag_node.rs

@@ -270,6 +270,11 @@ impl DAGOpNode {
         self.instruction.params.to_object(py)
     }
 
+    #[setter]
+    fn set_params(&mut self, val: smallvec::SmallVec<[crate::operations::Param; 3]>) {
+        self.instruction.params = val;
+    }
+
     pub fn is_parameterized(&self) -> bool {
         self.instruction.is_parameterized()
     }

qiskit/transpiler/passes/basis/basis_translator.py

@@ -30,11 +30,13 @@
     QuantumCircuit,
     ParameterExpression,
 )
-from qiskit.dagcircuit import DAGCircuit
+from qiskit.dagcircuit import DAGCircuit, DAGOpNode
 from qiskit.converters import circuit_to_dag, dag_to_circuit
 from qiskit.circuit.equivalence import Key, NodeData
 from qiskit.transpiler.basepasses import TransformationPass
 from qiskit.transpiler.exceptions import TranspilerError
+from qiskit.circuit.controlflow import CONTROL_FLOW_OP_NAMES
+from qiskit._accelerate.circuit import StandardGate
 
 logger = logging.getLogger(__name__)
 
@@ -253,7 +255,7 @@ def apply_translation(dag, wire_map):
                 node_qargs = tuple(wire_map[bit] for bit in node.qargs)
                 qubit_set = frozenset(node_qargs)
                 if node.name in target_basis or len(node.qargs) < self._min_qubits:
-                    if isinstance(node.op, ControlFlowOp):
+                    if node.name in CONTROL_FLOW_OP_NAMES:
                         flow_blocks = []
                         for block in node.op.blocks:
                             dag_block = circuit_to_dag(block)
@@ -281,7 +283,7 @@ def apply_translation(dag, wire_map):
                     continue
                 if qubit_set in extra_instr_map:
                     self._replace_node(dag, node, extra_instr_map[qubit_set])
-                elif (node.op.name, node.op.num_qubits) in instr_map:
+                elif (node.name, node.num_qubits) in instr_map:
                     self._replace_node(dag, node, instr_map)
                 else:
                     raise TranspilerError(f"BasisTranslator did not map {node.name}.")
@@ -298,20 +300,29 @@ def apply_translation(dag, wire_map):
         return dag
 
     def _replace_node(self, dag, node, instr_map):
-        target_params, target_dag = instr_map[node.op.name, node.op.num_qubits]
-        if len(node.op.params) != len(target_params):
+        target_params, target_dag = instr_map[node.name, node.num_qubits]
+        if len(node.params) != len(target_params):
             raise TranspilerError(
                 "Translation num_params not equal to op num_params."
-                f"Op: {node.op.params} {node.op.name} Translation: {target_params}\n{target_dag}"
+                f"Op: {node.params} {node.name} Translation: {target_params}\n{target_dag}"
             )
-        if node.op.params:
-            parameter_map = dict(zip(target_params, node.op.params))
+        if node.params:
+            parameter_map = dict(zip(target_params, node.params))
             bound_target_dag = target_dag.copy_empty_like()
             for inner_node in target_dag.topological_op_nodes():
-                if any(isinstance(x, ParameterExpression) for x in inner_node.op.params):
+                new_op = inner_node._raw_op
+                if not isinstance(inner_node._raw_op, StandardGate):
                     new_op = inner_node.op.copy()
+                new_node = DAGOpNode(
+                    new_op,
+                    qargs=inner_node.qargs,
+                    cargs=inner_node.cargs,
+                    params=inner_node.params,
+                    dag=bound_target_dag,
+                )
+                if any(isinstance(x, ParameterExpression) for x in inner_node.params):
                     new_params = []
-                    for param in new_op.params:
+                    for param in new_node.params:
                         if not isinstance(param, ParameterExpression):
                             new_params.append(param)
                         else:
@@ -325,10 +336,10 @@ def _replace_node(self, dag, node, instr_map):
                             if not new_value.parameters:
                                 new_value = new_value.numeric()
                             new_params.append(new_value)
-                    new_op.params = new_params
-                else:
-                    new_op = inner_node.op
-                bound_target_dag.apply_operation_back(new_op, inner_node.qargs, inner_node.cargs)
+                    new_node.params = new_params
+                    if not isinstance(new_op, StandardGate):
+                        new_op.params = new_params
+                bound_target_dag._apply_op_node_back(new_node)
             if isinstance(target_dag.global_phase, ParameterExpression):
                 old_phase = target_dag.global_phase
                 bind_dict = {x: parameter_map[x] for x in old_phase.parameters}
@@ -353,7 +364,7 @@ def _replace_node(self, dag, node, instr_map):
             dag_op = bound_target_dag.op_nodes()[0].op
             # dag_op may be the same instance as other ops in the dag,
             # so if there is a condition, need to copy
-            if getattr(node.op, "condition", None):
+            if getattr(node, "condition", None):
                 dag_op = dag_op.copy()
             dag.substitute_node(node, dag_op, inplace=True)
 
@@ -370,8 +381,8 @@ def _extract_basis(self, circuit):
     def _(self, dag: DAGCircuit):
         for node in dag.op_nodes():
             if not dag.has_calibration_for(node) and len(node.qargs) >= self._min_qubits:
-                yield (node.name, node.op.num_qubits)
-            if isinstance(node.op, ControlFlowOp):
+                yield (node.name, node.num_qubits)
+            if node.name in CONTROL_FLOW_OP_NAMES:
                 for block in node.op.blocks:
                     yield from self._extract_basis(block)
 
@@ -412,10 +423,10 @@ def _extract_basis_target(
                 frozenset(qargs).issuperset(incomplete_qargs)
                 for incomplete_qargs in self._qargs_with_non_global_operation
             ):
-                qargs_local_source_basis[frozenset(qargs)].add((node.name, node.op.num_qubits))
+                qargs_local_source_basis[frozenset(qargs)].add((node.name, node.num_qubits))
             else:
-                source_basis.add((node.name, node.op.num_qubits))
-            if isinstance(node.op, ControlFlowOp):
+                source_basis.add((node.name, node.num_qubits))
+            if node.name in CONTROL_FLOW_OP_NAMES:
                 for block in node.op.blocks:
                     block_dag = circuit_to_dag(block)
                     source_basis, qargs_local_source_basis = self._extract_basis_target(
@@ -628,7 +639,7 @@ def _compose_transforms(basis_transforms, source_basis, source_dag):
             doomed_nodes = [
                 node
                 for node in dag.op_nodes()
-                if (node.op.name, node.op.num_qubits) == (gate_name, gate_num_qubits)
+                if (node.name, node.num_qubits) == (gate_name, gate_num_qubits)
             ]
 
             if doomed_nodes and logger.isEnabledFor(logging.DEBUG):
@@ -642,9 +653,7 @@ def _compose_transforms(basis_transforms, source_basis, source_dag):
 
             for node in doomed_nodes:
 
-                replacement = equiv.assign_parameters(
-                    dict(zip_longest(equiv_params, node.op.params))
-                )
+                replacement = equiv.assign_parameters(dict(zip_longest(equiv_params, node.params)))
 
                 replacement_dag = circuit_to_dag(replacement)
 
@@ -666,8 +675,8 @@ def _get_example_gates(source_dag):
     def recurse(dag, example_gates=None):
         example_gates = example_gates or {}
         for node in dag.op_nodes():
-            example_gates[(node.op.name, node.op.num_qubits)] = node.op
-            if isinstance(node.op, ControlFlowOp):
+            example_gates[(node.name, node.num_qubits)] = node
+            if node.name in CONTROL_FLOW_OP_NAMES:
                 for block in node.op.blocks:
                     example_gates = recurse(circuit_to_dag(block), example_gates)
         return example_gates