bpo-41902: Micro optimization for range.index if step is 1 (GH-22479)
diff --git a/Objects/rangeobject.c b/Objects/rangeobject.c
index eaa48d5..babf55b 100644
--- a/Objects/rangeobject.c
+++ b/Objects/rangeobject.c
@@ -582,13 +582,19 @@ range_index(rangeobject *r, PyObject *ob)
return NULL;
if (contains) {
- PyObject *idx, *tmp = PyNumber_Subtract(ob, r->start);
- if (tmp == NULL)
+ PyObject *idx = PyNumber_Subtract(ob, r->start);
+ if (idx == NULL) {
return NULL;
+ }
+
+ if (r->step == _PyLong_One) {
+ return idx;
+ }
+
/* idx = (ob - r.start) // r.step */
- idx = PyNumber_FloorDivide(tmp, r->step);
- Py_DECREF(tmp);
- return idx;
+ PyObject *sidx = PyNumber_FloorDivide(idx, r->step);
+ Py_DECREF(idx);
+ return sidx;
}
/* object is not in the range */