From 5783fd2c58d068329c1ddeaea1db8acca5e2577b Mon Sep 17 00:00:00 2001 From: Victor Stinner Date: Sat, 19 Sep 2015 13:39:03 +0200 Subject: [PATCH] Issue #24999: In longobject.c, use two shifts instead of ">> 2*PyLong_SHIFT" to avoid undefined behaviour when LONG_MAX type is smaller than 60 bits. This change should fix a warning with the ICC compiler. --- Objects/longobject.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/Objects/longobject.c b/Objects/longobject.c index 40da0b15af1..5f224557d1f 100644 --- a/Objects/longobject.c +++ b/Objects/longobject.c @@ -4495,11 +4495,13 @@ _PyLong_GCD(PyObject *aarg, PyObject *barg) simple: assert(Py_REFCNT(a) > 0); assert(Py_REFCNT(b) > 0); -#if LONG_MAX >> 2*PyLong_SHIFT +/* Issue #24999: use two shifts instead of ">> 2*PyLong_SHIFT" to avoid + undefined behaviour when LONG_MAX type is smaller than 60 bits */ +#if LONG_MAX >> PyLong_SHIFT >> PyLong_SHIFT /* a fits into a long, so b must too */ x = PyLong_AsLong((PyObject *)a); y = PyLong_AsLong((PyObject *)b); -#elif defined(PY_LONG_LONG) && PY_LLONG_MAX >> 2*PyLong_SHIFT +#elif defined(PY_LONG_LONG) && PY_LLONG_MAX >> PyLong_SHIFT >> PyLong_SHIFT x = PyLong_AsLongLong((PyObject *)a); y = PyLong_AsLongLong((PyObject *)b); #else @@ -4516,9 +4518,9 @@ simple: y = x % y; x = t; } -#if LONG_MAX >> 2*PyLong_SHIFT +#if LONG_MAX >> PyLong_SHIFT >> PyLong_SHIFT return PyLong_FromLong(x); -#elif defined(PY_LONG_LONG) && PY_LLONG_MAX >> 2*PyLong_SHIFT +#elif defined(PY_LONG_LONG) && PY_LLONG_MAX >> PyLong_SHIFT >> PyLong_SHIFT return PyLong_FromLongLong(x); #else # error "_PyLong_GCD"