Split 2-tuple unpacking helper function into a (still) inlineable fast-path...

Split 2-tuple unpacking helper function into a (still) inlineable fast-path and a slow fallback function that does not need inlining.

Cython/Utility/ObjectHandling.c

@@ -80,49 +80,70 @@ static int __Pyx_IternextUnpackEndCheck(PyObject *retval, Py_ssize_t expected) {
 
 /////////////// UnpackTuple2.proto ///////////////
 
-static CYTHON_INLINE int __Pyx_unpack_tuple2(PyObject* tuple, PyObject** value1, PyObject** value2,
-                                             int is_tuple, int has_known_size, int decref_tuple);
+#define __Pyx_unpack_tuple2(tuple, value1, value2, is_tuple, has_known_size, decref_tuple) \
+    (likely(is_tuple || PyTuple_Check(tuple)) ? \
+        (likely(has_known_size || PyTuple_GET_SIZE(tuple) == 2) ? \
+            __Pyx_unpack_tuple2_exact(tuple, value1, value2, decref_tuple) : \
+            (__Pyx_UnpackTupleError(tuple, 2), -1)) : \
+        __Pyx_unpack_tuple2_generic(tuple, value1, value2, has_known_size, decref_tuple))
+
+static CYTHON_INLINE int __Pyx_unpack_tuple2_exact(
+    PyObject* tuple, PyObject** value1, PyObject** value2, int decref_tuple);
+static int __Pyx_unpack_tuple2_generic(
+    PyObject* tuple, PyObject** value1, PyObject** value2, int has_known_size, int decref_tuple);
 
 /////////////// UnpackTuple2 ///////////////
 //@requires: UnpackItemEndCheck
 //@requires: UnpackTupleError
 //@requires: RaiseNeedMoreValuesToUnpack
 
-static CYTHON_INLINE int __Pyx_unpack_tuple2(PyObject* tuple, PyObject** pvalue1, PyObject** pvalue2,
-                                             int is_tuple, int has_known_size, int decref_tuple) {
-    Py_ssize_t index;
-    PyObject *value1 = NULL, *value2 = NULL, *iter = NULL;
-    if (!is_tuple && unlikely(!PyTuple_Check(tuple))) {
-        iternextfunc iternext;
-        iter = PyObject_GetIter(tuple);
-        if (unlikely(!iter)) goto bad;
-        if (decref_tuple) { Py_DECREF(tuple); tuple = NULL; }
-        iternext = Py_TYPE(iter)->tp_iternext;
-        value1 = iternext(iter); if (unlikely(!value1)) { index = 0; goto unpacking_failed; }
-        value2 = iternext(iter); if (unlikely(!value2)) { index = 1; goto unpacking_failed; }
-        if (!has_known_size && unlikely(__Pyx_IternextUnpackEndCheck(iternext(iter), 2))) goto bad;
-        Py_DECREF(iter);
-    } else {
-        if (!has_known_size && unlikely(PyTuple_GET_SIZE(tuple) != 2)) {
-            __Pyx_UnpackTupleError(tuple, 2);
-            goto bad;
-        }
+static CYTHON_INLINE int __Pyx_unpack_tuple2_exact(
+        PyObject* tuple, PyObject** pvalue1, PyObject** pvalue2, int decref_tuple) {
+    PyObject *value1 = NULL, *value2 = NULL;
 #if CYTHON_COMPILING_IN_PYPY
-        value1 = PySequence_ITEM(tuple, 0);
-        if (unlikely(!value1)) goto bad;
-        value2 = PySequence_ITEM(tuple, 1);
-        if (unlikely(!value2)) goto bad;
+    value1 = PySequence_ITEM(tuple, 0);  if (unlikely(!value1)) goto bad;
+    value2 = PySequence_ITEM(tuple, 1);  if (unlikely(!value2)) goto bad;
 #else
-        value1 = PyTuple_GET_ITEM(tuple, 0);
-        value2 = PyTuple_GET_ITEM(tuple, 1);
-        Py_INCREF(value1);
-        Py_INCREF(value2);
+    value1 = PyTuple_GET_ITEM(tuple, 0);  Py_INCREF(value1);
+    value2 = PyTuple_GET_ITEM(tuple, 1);  Py_INCREF(value2);
 #endif
-        if (decref_tuple) { Py_DECREF(tuple); }
+    if (decref_tuple) {
+        Py_DECREF(tuple);
     }
+
     *pvalue1 = value1;
     *pvalue2 = value2;
     return 0;
+#if CYTHON_COMPILING_IN_PYPY
+bad:
+    Py_XDECREF(iter);
+    Py_XDECREF(value1);
+    Py_XDECREF(value2);
+    if (decref_tuple) { Py_XDECREF(tuple); }
+    return -1;
+#endif
+}
+
+static int __Pyx_unpack_tuple2_generic(PyObject* tuple, PyObject** pvalue1, PyObject** pvalue2,
+                                       int has_known_size, int decref_tuple) {
+    Py_ssize_t index;
+    PyObject *value1 = NULL, *value2 = NULL, *iter = NULL;
+    iternextfunc iternext;
+
+    iter = PyObject_GetIter(tuple);
+    if (unlikely(!iter)) goto bad;
+    if (decref_tuple) { Py_DECREF(tuple); tuple = NULL; }
+
+    iternext = Py_TYPE(iter)->tp_iternext;
+    value1 = iternext(iter); if (unlikely(!value1)) { index = 0; goto unpacking_failed; }
+    value2 = iternext(iter); if (unlikely(!value2)) { index = 1; goto unpacking_failed; }
+    if (!has_known_size && unlikely(__Pyx_IternextUnpackEndCheck(iternext(iter), 2))) goto bad;
+
+    Py_DECREF(iter);
+    *pvalue1 = value1;
+    *pvalue2 = value2;
+    return 0;
+
 unpacking_failed:
     if (!has_known_size && __Pyx_IterFinish() == 0)
         __Pyx_RaiseNeedMoreValuesError(index);
@@ -134,6 +155,7 @@ bad:
     return -1;
 }
 
+
 /////////////// IterNext.proto ///////////////
 
 #define __Pyx_PyIter_Next(obj) __Pyx_PyIter_Next2(obj, NULL)