https://github.com/python/cpython/commit/93930eaf0acd64dc0d08d58321d2682cb019bc1a
commit: 93930eaf0acd64dc0d08d58321d2682cb019bc1a
branch: main
author: Victor Stinner <[email protected]>
committer: vstinner <[email protected]>
date: 2024-01-10T16:38:56+01:00
summary:
gh-111139: Optimize math.gcd(int, int) (#113887)
Add a fast-path for the common case.
Benchmark:
python -m pyperf timeit \
-s 'import math; gcd=math.gcd; x=2*3; y=3*5' \
'gcd(x,y)'
Result: 1.07x faster (-3.4 ns)
Mean +- std dev: 52.6 ns +- 4.0 ns -> 49.2 ns +- 0.4 ns: 1.07x faster
files:
M Modules/mathmodule.c
diff --git a/Modules/mathmodule.c b/Modules/mathmodule.c
index 6cd61e9ab75424..2a796c1c55d2f0 100644
--- a/Modules/mathmodule.c
+++ b/Modules/mathmodule.c
@@ -759,13 +759,17 @@ m_log10(double x)
static PyObject *
math_gcd(PyObject *module, PyObject * const *args, Py_ssize_t nargs)
{
- PyObject *res, *x;
- Py_ssize_t i;
+ // Fast-path for the common case: gcd(int, int)
+ if (nargs == 2 && PyLong_CheckExact(args[0]) && PyLong_CheckExact(args[1]))
+ {
+ return _PyLong_GCD(args[0], args[1]);
+ }
if (nargs == 0) {
return PyLong_FromLong(0);
}
- res = PyNumber_Index(args[0]);
+
+ PyObject *res = PyNumber_Index(args[0]);
if (res == NULL) {
return NULL;
}
@@ -775,8 +779,8 @@ math_gcd(PyObject *module, PyObject * const *args,
Py_ssize_t nargs)
}
PyObject *one = _PyLong_GetOne(); // borrowed ref
- for (i = 1; i < nargs; i++) {
- x = _PyNumber_Index(args[i]);
+ for (Py_ssize_t i = 1; i < nargs; i++) {
+ PyObject *x = _PyNumber_Index(args[i]);
if (x == NULL) {
Py_DECREF(res);
return NULL;
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