bpo-41922: Use PEP 590 vectorcall to speed up reversed() (GH-22523)
diff --git a/Misc/NEWS.d/next/Core and Builtins/2020-10-04-01-02-58.bpo-41922.kHGT8I.rst b/Misc/NEWS.d/next/Core and Builtins/2020-10-04-01-02-58.bpo-41922.kHGT8I.rst
new file mode 100644
index 0000000..3c4de2c
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2020-10-04-01-02-58.bpo-41922.kHGT8I.rst
@@ -0,0 +1,2 @@
+Speed up calls to ``reversed()`` by using the :pep:`590` ``vectorcall``
+calling convention. Patch by Dong-hee Na.
diff --git a/Objects/enumobject.c b/Objects/enumobject.c
index 4a83bb4..9d8449b 100644
--- a/Objects/enumobject.c
+++ b/Objects/enumobject.c
@@ -314,6 +314,24 @@
return (PyObject *)ro;
}
+static PyObject *
+reversed_vectorcall(PyObject *type, PyObject * const*args,
+ size_t nargsf, PyObject *kwnames)
+{
+ assert(PyType_Check(type));
+
+ if (!_PyArg_NoKwnames("reversed", kwnames)) {
+ return NULL;
+ }
+
+ Py_ssize_t nargs = PyVectorcall_NARGS(nargsf);
+ if (!_PyArg_CheckPositional("reversed", nargs, 1, 1)) {
+ return NULL;
+ }
+
+ return reversed_new_impl((PyTypeObject *)type, args[0]);
+}
+
static void
reversed_dealloc(reversedobject *ro)
{
@@ -445,4 +463,5 @@
PyType_GenericAlloc, /* tp_alloc */
reversed_new, /* tp_new */
PyObject_GC_Del, /* tp_free */
+ .tp_vectorcall = (vectorcallfunc)reversed_vectorcall,
};
