Issue #13874: read_null() of faulthandler uses volatile to avoid optimisation
Clang 3.0 removes "y = *x;" instruction if the optimisation level is 3.
diff --git a/Modules/faulthandler.c b/Modules/faulthandler.c
index fcf4d01..f18bbbc 100644
--- a/Modules/faulthandler.c
+++ b/Modules/faulthandler.c
@@ -943,10 +943,13 @@
static PyObject *
faulthandler_read_null(PyObject *self, PyObject *args)
{
- int *x = NULL, y;
+ volatile int *x;
+ volatile int y;
int release_gil = 0;
if (!PyArg_ParseTuple(args, "|i:_read_null", &release_gil))
return NULL;
+
+ x = NULL;
if (release_gil) {
Py_BEGIN_ALLOW_THREADS
y = *x;