Optimize PyList_AsTuple(). Improve cache performance by doing the
pointer copy and object increment in one pass. For small lists,
save the overhead of the call to memcpy() -- this comes up in
calls like f(*listcomp).
diff --git a/Objects/listobject.c b/Objects/listobject.c
index ca767da..3fa256e 100644
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -2186,7 +2186,7 @@
PyList_AsTuple(PyObject *v)
{
PyObject *w;
- PyObject **p;
+ PyObject **p, **q;
Py_ssize_t n;
if (v == NULL || !PyList_Check(v)) {
PyErr_BadInternalCall();
@@ -2197,12 +2197,12 @@
if (w == NULL)
return NULL;
p = ((PyTupleObject *)w)->ob_item;
- memcpy((void *)p,
- (void *)((PyListObject *)v)->ob_item,
- n*sizeof(PyObject *));
+ q = ((PyListObject *)v)->ob_item;
while (--n >= 0) {
- Py_INCREF(*p);
+ Py_INCREF(*q);
+ *p = *q;
p++;
+ q++;
}
return w;
}