Mirror
/
cpython
mirror of https://github.com/python/cpython
4
1
Fork 0
Code Issues Releases Wiki Activity

bpo-27145: small_ints[x] could be returned in long_add and long_sub (GH-15716)

This commit is contained in:
HongWeipeng 2019-11-26 15:54:49 +08:00 committed by Inada Naoki
parent 386d00cc34
commit 036fe85bd3
3 changed files with 18 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
Lib/test/test_long.py
View File

@ -956,6 +956,14 @@ class LongTest(unittest.TestCase):
self.assertEqual(huge >> (sys.maxsize + 1), (1 << 499) + 5) self.assertEqual(huge >> (sys.maxsize + 1), (1 << 499) + 5)
self.assertEqual(huge >> (sys.maxsize + 1000), 0) self.assertEqual(huge >> (sys.maxsize + 1000), 0)
@support.cpython_only
def test_small_ints_in_huge_calculation(self):
a = 2 ** 100
b = -a + 1
c = a + 1
self.assertIs(a + b, 1)
self.assertIs(c - a, 1)
def test_small_ints(self): def test_small_ints(self):
for i in range(-5, 257): for i in range(-5, 257):
self.assertIs(i, i + 0) self.assertIs(i, i + 0)

1
Misc/NEWS.d/next/Core and Builtins/2019-09-06-16-40-12.bpo-27145.njuCXU.rst Normal file
View File

@ -0,0 +1 @@
int + int and int - int operators can now return small integer singletons. Patch by hongweipeng.

16
Objects/longobject.c
View File

@ -3206,7 +3206,7 @@ x_sub(PyLongObject *a, PyLongObject *b)
if (sign < 0) { if (sign < 0) {
Py_SIZE(z) = -Py_SIZE(z); Py_SIZE(z) = -Py_SIZE(z);
} }
return long_normalize(z); return maybe_small_long(long_normalize(z));
} }
static PyObject * static PyObject *
@ -3254,13 +3254,15 @@ long_sub(PyLongObject *a, PyLongObject *b)
return PyLong_FromLong(MEDIUM_VALUE(a) - MEDIUM_VALUE(b)); return PyLong_FromLong(MEDIUM_VALUE(a) - MEDIUM_VALUE(b));
} }
if (Py_SIZE(a) < 0) { if (Py_SIZE(a) < 0) {
if (Py_SIZE(b) < 0) if (Py_SIZE(b) < 0) {
z = x_sub(a, b); z = x_sub(b, a);
else }
else {
z = x_add(a, b); z = x_add(a, b);
if (z != NULL) { if (z != NULL) {
assert(Py_SIZE(z) == 0 || Py_REFCNT(z) == 1); assert(Py_SIZE(z) == 0 || Py_REFCNT(z) == 1);
Py_SIZE(z) = -(Py_SIZE(z)); Py_SIZE(z) = -(Py_SIZE(z));
}
} }
} }
else { else {