bpo-44698: Restore complex pow behaviour for small integral exponents (GH-27772) (GH-27796)
(cherry picked from commit 4b9a2dcf19e5d13c3bc2afea2de1f65cd994c699)
Co-authored-by: Mark Dickinson <mdickinson@enthought.com>
diff --git a/Objects/complexobject.c b/Objects/complexobject.c
index 05cae32..3e47949 100644
--- a/Objects/complexobject.c
+++ b/Objects/complexobject.c
@@ -172,14 +172,7 @@ c_powu(Py_complex x, long n)
static Py_complex
c_powi(Py_complex x, long n)
{
- Py_complex cn;
-
- if (n > 100 || n < -100) {
- cn.real = (double) n;
- cn.imag = 0.;
- return _Py_c_pow(x,cn);
- }
- else if (n > 0)
+ if (n > 0)
return c_powu(x,n);
else
return _Py_c_quot(c_1, c_powu(x,-n));
@@ -523,19 +516,12 @@ complex_pow(PyObject *v, PyObject *w, PyObject *z)
return NULL;
}
errno = 0;
- // Check if w is an integer value that fits inside a C long, so we can
- // use a faster algorithm. TO_COMPLEX(w, b), above, already handled the
- // conversion from larger longs, as well as other types.
- if (PyLong_Check(w)) {
- int overflow = 0;
- long int_exponent = PyLong_AsLongAndOverflow(w, &overflow);
- if (int_exponent == -1 && PyErr_Occurred())
- return NULL;
- if (overflow == 0)
- p = c_powi(a, int_exponent);
- else
- p = _Py_c_pow(a, b);
- } else {
+ // Check whether the exponent has a small integer value, and if so use
+ // a faster and more accurate algorithm.
+ if (b.imag == 0.0 && b.real == floor(b.real) && fabs(b.real) <= 100.0) {
+ p = c_powi(a, (long)b.real);
+ }
+ else {
p = _Py_c_pow(a, b);
}