From: Victor Stinner <vstinner@python.org>
Date: Tue, 27 Oct 2020 21:24:33 +0000 (+0100)
Subject: bpo-42161: Micro-optimize _collections._count_elements() (GH-23008)
X-Git-Tag: v3.10.0a2~50
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=35b95aaf21534e4a8e3370dfd6f7482265316c9e;p=thirdparty%2FPython%2Fcpython.git

bpo-42161: Micro-optimize _collections._count_elements() (GH-23008)

Move the _PyLong_GetOne() call outside the fast-path loop.
---

diff --git a/Modules/_collectionsmodule.c b/Modules/_collectionsmodule.c
index 8990071f519e..157875067635 100644
--- a/Modules/_collectionsmodule.c
+++ b/Modules/_collectionsmodule.c
@@ -2278,6 +2278,7 @@ _collections__count_elements_impl(PyObject *module, PyObject *mapping,
     PyObject *dict_get;
     PyObject *mapping_setitem;
     PyObject *dict_setitem;
+    PyObject *one = _PyLong_GetOne();  // borrowed reference
 
     it = PyObject_GetIter(iterable);
     if (it == NULL)
@@ -2324,10 +2325,10 @@ _collections__count_elements_impl(PyObject *module, PyObject *mapping,
             if (oldval == NULL) {
                 if (PyErr_Occurred())
                     goto done;
-                if (_PyDict_SetItem_KnownHash(mapping, key, _PyLong_GetOne(), hash) < 0)
+                if (_PyDict_SetItem_KnownHash(mapping, key, one, hash) < 0)
                     goto done;
             } else {
-                newval = PyNumber_Add(oldval, _PyLong_GetOne());
+                newval = PyNumber_Add(oldval, one);
                 if (newval == NULL)
                     goto done;
                 if (_PyDict_SetItem_KnownHash(mapping, key, newval, hash) < 0)
@@ -2336,13 +2337,13 @@ _collections__count_elements_impl(PyObject *module, PyObject *mapping,
             }
             Py_DECREF(key);
         }
-    } else {
+    }
+    else {
         bound_get = _PyObject_GetAttrId(mapping, &PyId_get);
         if (bound_get == NULL)
             goto done;
 
         PyObject *zero = _PyLong_GetZero();  // borrowed reference
-        PyObject *one = _PyLong_GetOne();  // borrowed reference
         while (1) {
             key = PyIter_Next(it);
             if (key == NULL)