asvetlov · Nov 12, 2026
diff --git a/Doc/library/dis.rst b/Doc/library/dis.rst
@@ -832,11 +832,16 @@ not have to be) the original ``STACK[-2]``.
 
 .. opcode:: GET_ANEXT
 
-   Implement ``STACK.append(get_awaitable(STACK[-1].__anext__()))`` to the stack.
+   Implement ``STACK.append(get_awaitable(STACK[-1].__anext__()))`` to the stack,
+   then push ``NULL`` and ``None``, ready for :opcode:`SEND`.
    See ``GET_AWAITABLE`` for details about ``get_awaitable``.
 
    .. versionadded:: 3.5
 
+   .. versionchanged:: next
+      Also pushes ``NULL`` and ``None``, which were previously pushed by
+      separate instructions.
+
 
 .. opcode:: END_ASYNC_FOR
 

diff --git a/Include/internal/pycore_magic_number.h b/Include/internal/pycore_magic_number.h
@@ -304,6 +304,7 @@ Known values:
     Python 3.16a1 3704 (Replace DELETE_ATTR with PUSH_NULL; STORE_ATTR)
     Python 3.16a1 3705 (Add INTRINSIC_ADD_CONDITIONAL_ANNOTATION)
     Python 3.16a1 3706 (Add INTRINSIC_MATCH_CLASS_ISINSTANCE)
+    Python 3.16a1 3707 (GET_ANEXT also pushes NULL and None for SEND)
 
     Python 3.17 will start with 3750
 
@@ -313,7 +314,7 @@ Known values:
 
 */
 
-#define PYC_MAGIC_NUMBER 3706
+#define PYC_MAGIC_NUMBER 3707
 /* This is equivalent to converting PYC_MAGIC_NUMBER to 2 bytes
    (little-endian) and then appending b'\r\n'. */
 #define PYC_MAGIC_NUMBER_TOKEN \

diff --git a/Include/internal/pycore_opcode_metadata.h b/Include/internal/pycore_opcode_metadata.h
diff --git a/Include/internal/pycore_uop_ids.h b/Include/internal/pycore_uop_ids.h
diff --git a/Include/internal/pycore_uop_metadata.h b/Include/internal/pycore_uop_metadata.h
diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-11-12-14-46-10.gh-issue-161875.oOjR9w.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-11-12-14-46-10.gh-issue-161875.oOjR9w.rst
@@ -0,0 +1,4 @@
+The :opcode:`GET_ANEXT` instruction now also pushes the ``NULL`` and
+``None`` that start the :opcode:`SEND` loop, so each :keyword:`async for`
+iteration no longer needs separate :opcode:`PUSH_NULL` and ``LOAD_CONST None``
+instructions.
diff --git a/Modules/_testinternalcapi/test_cases.c.h b/Modules/_testinternalcapi/test_cases.c.h
@@ -1641,12 +1641,14 @@ dummy_func(
             iter = PyStackRef_FromPyObjectSteal(iter_o);
         }
 
-        inst(GET_ANEXT, (aiter -- aiter, awaitable)) {
+        inst(GET_ANEXT, (aiter -- aiter, awaitable, null, none)) {
             PyObject *awaitable_o = _PyEval_GetANext(PyStackRef_AsPyObjectBorrow(aiter));
             if (awaitable_o == NULL) {
                 ERROR_NO_POP();
             }
             awaitable = PyStackRef_FromPyObjectSteal(awaitable_o);
+            null = PyStackRef_NULL;
+            none = PyStackRef_None;
         }
 
         inst(GET_AWAITABLE, (iterable -- iter)) {

@@ -2225,8 +2225,6 @@ codegen_async_for(compiler *c, stmt_ty s)
     /* SETUP_FINALLY to guard the __anext__ call */
     ADDOP_JUMP(c, loc, SETUP_FINALLY, except);
     ADDOP(c, loc, GET_ANEXT);
-    ADDOP(c, loc, PUSH_NULL);
-    ADDOP_LOAD_CONST(c, loc, Py_None);
     USE_LABEL(c, send);
     ADD_YIELD_FROM(c, loc, 1);
     ADDOP(c, loc, POP_BLOCK);  /* for SETUP_FINALLY */
@@ -4843,8 +4841,6 @@ codegen_async_comprehension_generator(compiler *c, location loc,
 
     ADDOP_JUMP(c, loc, SETUP_FINALLY, except);
     ADDOP(c, loc, GET_ANEXT);
-    ADDOP(c, loc, PUSH_NULL);
-    ADDOP_LOAD_CONST(c, loc, Py_None);
     USE_LABEL(c, send);
     ADD_YIELD_FROM(c, loc, 1);
     ADDOP(c, loc, POP_BLOCK);

diff --git a/Python/executor_cases.c.h b/Python/executor_cases.c.h
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
@@ -2763,13 +2763,15 @@ dummy_func(void) {
         }
     }
 
-    op(_GET_ANEXT, (aiter -- aiter, awaitable)) {
+    op(_GET_ANEXT, (aiter -- aiter, awaitable, null, none)) {
         if (sym_matches_type(aiter, &PyAsyncGen_Type)) {
             awaitable = sym_new_type(ctx, &_PyAsyncGenASend_Type);
         }
         else {
             awaitable = sym_new_not_null(ctx);
         }
+        null = PyJitRef_Borrow(sym_new_null(ctx));
+        none = PyJitRef_Borrow(sym_new_const(ctx, Py_None));
     }
 
 // END BYTECODES //

diff --git a/Python/optimizer_cases.c.h b/Python/optimizer_cases.c.h