Use a dedicated C macro for CyFunction type checks instead of repeating the TypeCheck() call.

Cython/Utility/CythonFunction.c

@@ -47,6 +47,8 @@ typedef struct {
 
 static PyTypeObject *__pyx_CyFunctionType = 0;
 
+#define __Pyx_CyFunction_Check(obj)  (__Pyx_TypeCheck(obj, __pyx_CyFunctionType))
+
 #define __Pyx_CyFunction_NewEx(ml, flags, qualname, self, module, globals, code) \
     __Pyx_CyFunction_New(__pyx_CyFunctionType, ml, flags, qualname, self, module, globals, code)
 
@@ -1255,7 +1257,7 @@ static PyObject* __Pyx_Method_ClassMethod(PyObject *method) {
         return PyClassMethod_New(method);
     }
 #ifdef __Pyx_CyFunction_USED
-    else if (__Pyx_TypeCheck(method, __pyx_CyFunctionType)) {
+    else if (__Pyx_CyFunction_Check(method)) {
         return PyClassMethod_New(method);
     }
 #endif

Cython/Utility/ObjectHandling.c

@@ -2234,10 +2234,11 @@ static CYTHON_INLINE PyObject* __Pyx_PyObject_CallNoArg(PyObject *func) {
     }
 #endif
 #ifdef __Pyx_CyFunction_USED
-    if (likely(PyCFunction_Check(func) || __Pyx_TypeCheck(func, __pyx_CyFunctionType))) {
+    if (likely(PyCFunction_Check(func) || __Pyx_CyFunction_Check(func)))
 #else
-    if (likely(PyCFunction_Check(func))) {
+    if (likely(PyCFunction_Check(func)))
 #endif
+    {
         if (likely(PyCFunction_GET_FLAGS(func) & METH_NOARGS)) {
             // fast and simple case that we are optimising for
             return __Pyx_PyObject_CallMethO(func, NULL);