diff -r 2c8b81c87520 -r 8dcb1e2a04a0 Include/pythonrun.h
--- a/Include/pythonrun.h	Fri Jan 22 17:43:39 2016 +0100
+++ b/Include/pythonrun.h	Fri Jan 22 23:19:28 2016 +0100
@@ -16,6 +16,7 @@ extern "C" {
 #define PyCF_DONT_IMPLY_DEDENT 0x0200
 #define PyCF_ONLY_AST 0x0400
 #define PyCF_IGNORE_COOKIE 0x0800
+#define PyCF_TRANSFORMED_AST 0x1000

 #ifndef Py_LIMITED_API
 typedef struct {

diff -r 2c8b81c87520 -r 8dcb1e2a04a0 Lib/test/test_pep511.py
--- a/Lib/test/test_pep511.py	Fri Jan 22 17:43:39 2016 +0100
+++ b/Lib/test/test_pep511.py	Fri Jan 22 23:19:28 2016 +0100
@@ -69,7 +69,8 @@ class CodeTransformerTests(unittest.Test
         expected = ast.parse('print("Ni! Ni! Ni!")')

         sys.set_code_transformers([ASTTransformer()])
-        tree = ast.parse('print("Hello World")')
+        tree = compile('print("Hello World")', 'string', 'exec',
+                       flags=ast.PyCF_TRANSFORMED_AST)
         self.assertEqual(ast.dump(tree), ast.dump(expected))

     def test_ast_call(self):
diff -r 2c8b81c87520 -r 8dcb1e2a04a0 Parser/asdl_c.py
--- a/Parser/asdl_c.py	Fri Jan 22 17:43:39 2016 +0100
+++ b/Parser/asdl_c.py	Fri Jan 22 23:19:28 2016 +0100
@@ -1035,6 +1035,8 @@ class ASTModuleVisitor(PickleVisitor):
         self.emit('if (PyDict_SetItemString(d, "AST", (PyObject*)&AST_type) < 0) return NULL;', 1)
         self.emit('if (PyModule_AddIntMacro(m, PyCF_ONLY_AST) < 0)', 1)
         self.emit("return NULL;", 2)
+        self.emit('if (PyModule_AddIntMacro(m, PyCF_TRANSFORMED_AST) < 0)', 1)
+        self.emit("return NULL;", 2)
         for dfn in mod.dfns:
             self.visit(dfn)
         self.emit("return m;", 1)
diff -r 2c8b81c87520 -r 8dcb1e2a04a0 Python/Python-ast.c
--- a/Python/Python-ast.c	Fri Jan 22 17:43:39 2016 +0100
+++ b/Python/Python-ast.c	Fri Jan 22 23:19:28 2016 +0100
@@ -7500,6 +7500,8 @@ PyInit__ast(void)
     if (PyDict_SetItemString(d, "AST", (PyObject*)&AST_type) < 0) return NULL;
     if (PyModule_AddIntMacro(m, PyCF_ONLY_AST) < 0)
         return NULL;
+    if (PyModule_AddIntMacro(m, PyCF_TRANSFORMED_AST) < 0)
+        return NULL;
     if (PyDict_SetItemString(d, "mod", (PyObject*)mod_type) < 0) return NULL;
     if (PyDict_SetItemString(d, "Module", (PyObject*)Module_type) < 0) return
         NULL;
diff -r 2c8b81c87520 -r 8dcb1e2a04a0 Python/bltinmodule.c
--- a/Python/bltinmodule.c	Fri Jan 22 17:43:39 2016 +0100
+++ b/Python/bltinmodule.c	Fri Jan 22 23:19:28 2016 +0100
@@ -688,7 +688,8 @@ builtin_compile_impl(PyModuleDef *module
     cf.cf_flags = flags | PyCF_SOURCE_IS_UTF8;

     if (flags &
-        ~(PyCF_MASK | PyCF_MASK_OBSOLETE | PyCF_DONT_IMPLY_DEDENT | PyCF_ONLY_AST))
+        ~(PyCF_MASK | PyCF_MASK_OBSOLETE | PyCF_DONT_IMPLY_DEDENT
+                    | PyCF_ONLY_AST | PyCF_TRANSFORMED_AST))
     {
         PyErr_SetString(PyExc_ValueError,
                         "compile(): unrecognised flags");
@@ -722,7 +723,7 @@ builtin_compile_impl(PyModuleDef *module
     if (is_ast == -1)
         goto error;
     if (is_ast) {
-        if (flags & PyCF_ONLY_AST) {
+        if (flags & (PyCF_ONLY_AST | PyCF_TRANSFORMED_AST)) {
             Py_INCREF(source);
             result = source;
         }
diff -r 2c8b81c87520 -r 8dcb1e2a04a0 Python/pythonrun.c
--- a/Python/pythonrun.c	Fri Jan 22 17:43:39 2016 +0100
+++ b/Python/pythonrun.c	Fri Jan 22 23:19:28 2016 +0100
@@ -1024,7 +1024,7 @@ Py_CompileStringObject(const char *str,
         PyArena_Free(arena);
         return NULL;
     }
-    if (flags && (flags->cf_flags & PyCF_ONLY_AST)) {
+    if (flags && (flags->cf_flags & (PyCF_ONLY_AST | PyCF_TRANSFORMED_AST))) {
         PyObject *result = PyAST_mod2obj(mod);
         PyArena_Free(arena);
         return result;
@@ -1112,7 +1112,8 @@ ast_transformers_context(PyObject *filen
 }

 static mod_ty
-ast_transformers(mod_ty mod, PyArena *arena, PyObject *filename, int start)
+ast_transformers(mod_ty mod, PyArena *arena, int cf_flags,
+                 PyObject *filename, int start)
 {
     PyObject *ast, *context = NULL;
     int mode;
@@ -1121,6 +1122,9 @@ ast_transformers(mod_ty mod, PyArena *ar

     assert(filename != NULL);

+    if (cf_flags & PyCF_ONLY_AST)
+        return mod;
+
     if (_PySys_GetCodeTransformers(&transformers, &ntransformer) < 0) {
         PyErr_SetString(PyExc_RuntimeError,
                 "failed to get code transformers");
@@ -1223,7 +1227,7 @@ PyParser_ASTFromStringObject(const char
     if (mod == NULL)
         return NULL;

-    return ast_transformers(mod, arena, filename, start);
+    return ast_transformers(mod, arena, flags->cf_flags, filename, start);
 }

 mod_ty
@@ -1273,7 +1277,7 @@ PyParser_ASTFromFileObject(FILE *fp, PyO
     if (mod == NULL)
         return NULL;

-    return ast_transformers(mod, arena, filename, start);
+    return ast_transformers(mod, arena, flags->cf_flags, filename, start);
 }

 mod_ty