bpo-35696: Simplify long_compare() (GH-16146)

Author: hongweipeng

Objects/longobject.c

@@ -3028,33 +3028,32 @@ PyLong_AsDouble(PyObject *v)
 
 /* Methods */
 
-static int
+/* if a < b, return a negative number
+ if a == b, return 0
+ if a > b, return a positive number */
+
+static Py_ssize_t
 long_compare(PyLongObject *a, PyLongObject *b)
 {
- Py_ssize_t sign;
-
- if (Py_SIZE(a) != Py_SIZE(b)) {
- sign = Py_SIZE(a) - Py_SIZE(b);
- }
- else {
+ Py_ssize_t sign = Py_SIZE(a) - Py_SIZE(b);
+ if (sign == 0) {
  Py_ssize_t i = Py_ABS(Py_SIZE(a));
- while (--i >= 0 && a->ob_digit[i] == b->ob_digit[i])
- ;
- if (i < 0)
- sign = 0;
- else {
- sign = (sdigit)a->ob_digit[i] - (sdigit)b->ob_digit[i];
- if (Py_SIZE(a) < 0)
- sign = -sign;
+ sdigit diff = 0;
+ while (--i >= 0) {
+ diff = (sdigit) a->ob_digit[i] - (sdigit) b->ob_digit[i];
+ if (diff) {
+ break;
+ }
  }
+ sign = Py_SIZE(a) < 0 ? -diff : diff;
  }
- return sign < 0 ? -1 : sign > 0 ? 1 : 0;
+ return sign;
 }
 
 static PyObject *
 long_richcompare(PyObject *self, PyObject *other, int op)
 {
- int result;
+ Py_ssize_t result;
  CHECK_BINOP(self, other);
  if (self == other)
  result = 0;
@@ -5210,7 +5209,8 @@ _PyLong_DivmodNear(PyObject *a, PyObject *b)
 {
  PyLongObject *quo = NULL, *rem = NULL;
  PyObject *twice_rem, *result, *temp;
- int cmp, quo_is_odd, quo_is_neg;
+ int quo_is_odd, quo_is_neg;
+ Py_ssize_t cmp;
 
  /* Equivalent Python code: