inline PyList_Append() a bit more

Cython/Compiler/Builtin.py

@@ -277,7 +277,8 @@ builtin_types_table = [
 
     ("list",    "PyList_Type",     [BuiltinMethod("insert",  "TzO",  "r", "PyList_Insert"),
                                     BuiltinMethod("reverse", "T",    "r", "PyList_Reverse"),
-                                    BuiltinMethod("append",  "TO",   "r", "PyList_Append"),
+                                    BuiltinMethod("append",  "TO",   "r", "__Pyx_PyList_Append",
+                                                  utility_code=UtilityCode.load("ListAppend", "Optimize.c")),
                                     ]),
 
     ("dict",    "PyDict_Type",     [BuiltinMethod("items", "T",   "O", "PyDict_Items"),  # FIXME: Py3 mode?

Cython/Compiler/ExprNodes.py

@@ -5899,8 +5899,9 @@ class ComprehensionAppendNode(Node):
 
     def generate_execution_code(self, code):
         if self.target.type is list_type:
-            code.globalstate.use_utility_code(UtilityCode.load_cached("InternalListAppend", "Optimize.c"))
-            function = "__Pyx_PyList_Append"
+            code.globalstate.use_utility_code(
+                UtilityCode.load_cached("ListCompAppend", "Optimize.c"))
+            function = "__Pyx_ListComp_Append"
         elif self.target.type is set_type:
             function = "PySet_Add"
         else:

Cython/Utility/Optimize.c

@@ -3,10 +3,11 @@
 static CYTHON_INLINE PyObject* __Pyx_PyObject_Append(PyObject* L, PyObject* x); /*proto*/
 
 /////////////// append ///////////////
+//@requires: ListAppend
 
 static CYTHON_INLINE PyObject* __Pyx_PyObject_Append(PyObject* L, PyObject* x) {
     if (likely(PyList_CheckExact(L))) {
-        if (unlikely(PyList_Append(L, x) < 0)) return NULL;
+        if (unlikely(__Pyx_PyList_Append(L, x) < 0)) return NULL;
         Py_INCREF(Py_None);
         return Py_None; /* this is just to have an accurate signature */
     } else {
@@ -14,13 +15,13 @@ static CYTHON_INLINE PyObject* __Pyx_PyObject_Append(PyObject* L, PyObject* x) {
     }
 }
 
-/////////////// InternalListAppend.proto ///////////////
+/////////////// ListAppend.proto ///////////////
 
 #if CYTHON_COMPILING_IN_CPYTHON
 static CYTHON_INLINE int __Pyx_PyList_Append(PyObject* list, PyObject* x) {
     PyListObject* L = (PyListObject*) list;
     Py_ssize_t len = Py_SIZE(list);
-    if (likely(L->allocated > len)) {
+    if (likely(L->allocated > len) & likely(len > (L->allocated >> 1))) {
         Py_INCREF(x);
         PyList_SET_ITEM(list, len, x);
         Py_SIZE(list) = len+1;
@@ -32,6 +33,24 @@ static CYTHON_INLINE int __Pyx_PyList_Append(PyObject* list, PyObject* x) {
 #define __Pyx_PyList_Append(L,x) PyList_Append(L,x)
 #endif
 
+/////////////// ListCompAppend.proto ///////////////
+
+#if CYTHON_COMPILING_IN_CPYTHON
+static CYTHON_INLINE int __Pyx_ListComp_Append(PyObject* list, PyObject* x) {
+    PyListObject* L = (PyListObject*) list;
+    Py_ssize_t len = Py_SIZE(list);
+    if (likely(L->allocated > len)) {
+        Py_INCREF(x);
+        PyList_SET_ITEM(list, len, x);
+        Py_SIZE(list) = len+1;
+        return 0;
+    }
+    return PyList_Append(list, x);
+}
+#else
+#define __Pyx_ListComp_Append(L,x) PyList_Append(L,x)
+#endif
+
 /////////////// pop.proto ///////////////
 
 static CYTHON_INLINE PyObject* __Pyx_PyObject_Pop(PyObject* L); /*proto*/