Issue #2183: Simplify and optimize bytecode for list comprehensions.
diff --git a/Python/ceval.c b/Python/ceval.c
index bd35185..09501af 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -1294,9 +1294,8 @@
 
 		case LIST_APPEND:
 			w = POP();
-			v = POP();
+			v = stack_pointer[-oparg];
 			err = PyList_Append(v, w);
-			Py_DECREF(v);
 			Py_DECREF(w);
 			if (err == 0) {
 				PREDICT(JUMP_ABSOLUTE);