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| author | Martin v. Löwis <martin@v.loewis.de> | 2006-10-04 05:47:47 +0000 |
|---|---|---|
| committer | Martin v. Löwis <martin@v.loewis.de> | 2006-10-04 05:47:47 +0000 |
| commit | 10525ad31383e33c6e2dcdfcc9180ada55fa3b50 (patch) | |
| tree | d089bc2b2ef19eb4ced5b07150db8038e0399ca8 | |
| parent | a027bac30aef8eeb129a9173dfc1c4dfedc44993 (diff) | |
| download | cpython-git-10525ad31383e33c6e2dcdfcc9180ada55fa3b50.tar.gz | |
Fix integer negation and absolute value to not rely
on undefined behaviour of the C compiler anymore.
| -rw-r--r-- | Lib/test/test_builtin.py | 1 | ||||
| -rw-r--r-- | Misc/NEWS | 3 | ||||
| -rw-r--r-- | Objects/intobject.c | 7 |
3 files changed, 7 insertions, 4 deletions
diff --git a/Lib/test/test_builtin.py b/Lib/test/test_builtin.py index ca7a8f38c0..f3bdbe29c4 100644 --- a/Lib/test/test_builtin.py +++ b/Lib/test/test_builtin.py @@ -116,6 +116,7 @@ class BuiltinTest(unittest.TestCase): self.assertEqual(abs(0), 0) self.assertEqual(abs(1234), 1234) self.assertEqual(abs(-1234), 1234) + self.assertTrue(abs(-sys.maxint-1) > 0) # float self.assertEqual(abs(0.0), 0.0) self.assertEqual(abs(3.14), 3.14) @@ -12,6 +12,9 @@ What's New in Python 2.5.1c1? Core and builtins ----------------- +- Integer negation and absolute value were fixed to not rely + on undefined behaviour of the C compiler anymore. + - Bug #1566800: make sure that EnvironmentError can be called with any number of arguments, as was the case in Python 2.4. diff --git a/Objects/intobject.c b/Objects/intobject.c index b94e3e9887..28f7606710 100644 --- a/Objects/intobject.c +++ b/Objects/intobject.c @@ -760,10 +760,9 @@ int_pow(PyIntObject *v, PyIntObject *w, PyIntObject *z) static PyObject * int_neg(PyIntObject *v) { - register long a, x; + register long a; a = v->ob_ival; - x = -a; - if (a < 0 && x < 0) { + if (a < 0 && (unsigned long)a == 0-(unsigned long)a) { PyObject *o = PyLong_FromLong(a); if (o != NULL) { PyObject *result = PyNumber_Negative(o); @@ -772,7 +771,7 @@ int_neg(PyIntObject *v) } return NULL; } - return PyInt_FromLong(x); + return PyInt_FromLong(-a); } static PyObject * |