Add a dedicated subtype check function for testing against two possible base...

Add a dedicated subtype check function for testing against two possible base classes in Py3 (currently used for generator exception checks).

Cython/Utility/ModuleSetupCode.c

@@ -970,6 +970,24 @@ static CYTHON_INLINE int __Pyx_IsSubtype(PyTypeObject *a, PyTypeObject *b) {
     return __Pyx_InBases(a, b);
 }
 
+static CYTHON_INLINE int __Pyx_IsAnySubtype2(PyTypeObject *cls, PyTypeObject *a, PyTypeObject *b) {
+    PyObject *mro;
+    if (cls == a || cls == b) return 1;
+    mro = cls->tp_mro;
+    if (likely(mro)) {
+        Py_ssize_t i, n;
+        n = PyTuple_GET_SIZE(mro);
+        for (i = 0; i < n; i++) {
+            PyObject *base = PyTuple_GET_ITEM(mro, i);
+            if (base == (PyObject *)a || base == (PyObject *)b)
+                return 1;
+        }
+        return 0;
+    }
+    // should only get here for incompletely initialised types, i.e. never under normal usage patterns
+    return __Pyx_InBases(cls, a) || __Pyx_InBases(cls, b);
+}
+
 
 #if PY_MAJOR_VERSION == 2
 static int __Pyx_inner_PyErr_GivenExceptionMatches2(PyObject *err, PyObject* exc_type1, PyObject* exc_type2) {
@@ -1000,11 +1018,11 @@ static int __Pyx_inner_PyErr_GivenExceptionMatches2(PyObject *err, PyObject* exc
 }
 #else
 static CYTHON_INLINE int __Pyx_inner_PyErr_GivenExceptionMatches2(PyObject *err, PyObject* exc_type1, PyObject *exc_type2) {
-    int res = exc_type1 ? __Pyx_IsSubtype((PyTypeObject*)err, (PyTypeObject*)exc_type1) : 0;
-    if (!res) {
-        res = __Pyx_IsSubtype((PyTypeObject*)err, (PyTypeObject*)exc_type2);
+    if (exc_type1) {
+        return __Pyx_IsAnySubtype2((PyTypeObject*)err, (PyTypeObject*)exc_type1, (PyTypeObject*)exc_type2);
+    } else {
+        return __Pyx_IsSubtype((PyTypeObject*)err, (PyTypeObject*)exc_type2);
     }
-    return res;
 }
 #endif