Fix bug in circuit decompose (#8364)

* fix bug in circuit decompose * add test * Update test/python/circuit/test_circuit_operations.py Co-authored-by: Matthew Treinish <[email protected]> Co-authored-by: Matthew Treinish <[email protected]> Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
Qiskit · Jul 19, 2022 · 7753560 · 7753560
1 parent 6dd0d69
commit 7753560
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Showing 3 changed files with 12 additions and 3 deletions.
diff --git a/qiskit/transpiler/passes/basis/decompose.py b/qiskit/transpiler/passes/basis/decompose.py
@@ -128,9 +128,7 @@ def _should_decompose(self, node) -> bool:
             node.name in gates or any(fnmatch(node.name, p) for p in strings_list)
         ):
             return True
-        elif not has_label and (  # check if Gate type given
-            any(isinstance(node.op, op) for op in gate_type_list)
-        ):
+        elif any(isinstance(node.op, op) for op in gate_type_list):  # check if Gate type given
             return True
         else:
             return False
diff --git a/releasenotes/notes/decompose-fix-993f7242eaa69407.yaml b/releasenotes/notes/decompose-fix-993f7242eaa69407.yaml
@@ -0,0 +1,4 @@
+---
+fixes:
+  - Fixed a bug in :meth:`.QuantumCircuit.decompose` that caused the
+    `gates_to_decompose` argument to be handled incorrectly.
diff --git a/test/python/circuit/test_circuit_operations.py b/test/python/circuit/test_circuit_operations.py
@@ -1265,3 +1265,10 @@ def test_pop_previous_instruction_removes_parameters(self):
         instruction = test._pop_previous_instruction_in_scope()
         self.assertEqual(list(last_instructions), [instruction])
         self.assertEqual({y}, set(test.parameters))
+
+    def test_decompose_gate_type(self):
+        """Test decompose specifying gate type."""
+        circuit = QuantumCircuit(1)
+        circuit.append(SGate(label="s_gate"), [0])
+        decomposed = circuit.decompose(gates_to_decompose=SGate)
+        self.assertNotIn("s", decomposed.count_ops())