Expand Up @@ -234,6 +234,12 @@ PyList_SetItem(PyObject *op, Py_ssize_t i, return 0; }

/* Threshold at which to switch to using * memmove instead of a for loop in ins1 */ #define INS1_MEMMOVE_THRESHOLD 32
static int ins1(PyListObject *self, Py_ssize_t where, PyObject *v) { Expand All @@ -256,12 +262,15 @@ ins1(PyListObject *self, Py_ssize_t where, PyObject *v) where += n; if (where < 0) where = 0; } if (where > n) } else if (where > n) where = n; items = self->ob_item; for (i = n; --i >= where; ) items[i+1] = items[i]; if (n <= INS1_MEMMOVE_THRESHOLD) for (i = n; --i >= where; ) items[i+1] = items[i]; else memmove(&items[where+1], &items[where], sizeof(PyObject*) * (n - where)); Py_INCREF(v); items[where] = v; return 0; Expand Down