GH-122155: Track local variables between pops and pushes in cases generator (GH-122286)

4 files changed, 192 insertions, 48 deletions

diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index 4afce2c..abfd803 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -1357,8 +1357,8 @@ dummy_func(
             (void)counter;
         }
 
-        op(_UNPACK_SEQUENCE, (seq -- unused[oparg])) {
-            _PyStackRef *top = stack_pointer + oparg - 1;
+        op(_UNPACK_SEQUENCE, (seq -- output[oparg])) {
+            _PyStackRef *top = output + oparg;
             int res = _PyEval_UnpackIterableStackRef(tstate, seq, oparg, -1, top);
             DECREF_INPUTS();
             ERROR_IF(res == 0, error);
@@ -1401,9 +1401,8 @@ dummy_func(
             DECREF_INPUTS();
         }
 
-        inst(UNPACK_EX, (seq -- unused[oparg & 0xFF], unused, unused[oparg >> 8])) {
-            int totalargs = 1 + (oparg & 0xFF) + (oparg >> 8);
-            _PyStackRef *top = stack_pointer + totalargs - 1;
+        inst(UNPACK_EX, (seq -- left[oparg & 0xFF], unused, right[oparg >> 8])) {
+            _PyStackRef *top = right + (oparg >> 8);
             int res = _PyEval_UnpackIterableStackRef(tstate, seq, oparg & 0xFF, oparg >> 8, top);
             DECREF_INPUTS();
             ERROR_IF(res == 0, error);
diff --git a/Python/executor_cases.c.h b/Python/executor_cases.c.h
index 6265403..f0acc3b 100644
--- a/Python/executor_cases.c.h
+++ b/Python/executor_cases.c.h
@@ -1440,9 +1440,11 @@
 
         case _UNPACK_SEQUENCE: {
             _PyStackRef seq;
+            _PyStackRef *output;
             oparg = CURRENT_OPARG();
             seq = stack_pointer[-1];
-            _PyStackRef *top = stack_pointer + oparg - 1;
+            output = &stack_pointer[-1];
+            _PyStackRef *top = output + oparg;
             int res = _PyEval_UnpackIterableStackRef(tstate, seq, oparg, -1, top);
             PyStackRef_CLOSE(seq);
             if (res == 0) JUMP_TO_ERROR();
@@ -1532,14 +1534,15 @@
 
         case _UNPACK_EX: {
             _PyStackRef seq;
+            _PyStackRef *right;
             oparg = CURRENT_OPARG();
             seq = stack_pointer[-1];
-            int totalargs = 1 + (oparg & 0xFF) + (oparg >> 8);
-            _PyStackRef *top = stack_pointer + totalargs - 1;
+            right = &stack_pointer[(oparg & 0xFF)];
+            _PyStackRef *top = right + (oparg >> 8);
             int res = _PyEval_UnpackIterableStackRef(tstate, seq, oparg & 0xFF, oparg >> 8, top);
             PyStackRef_CLOSE(seq);
             if (res == 0) JUMP_TO_ERROR();
-            stack_pointer += (oparg >> 8) + (oparg & 0xFF);
+            stack_pointer += (oparg & 0xFF) + (oparg >> 8);
             assert(WITHIN_STACK_BOUNDS());
             break;
         }
@@ -3595,6 +3598,7 @@
             args = &stack_pointer[-oparg];
             self_or_null = stack_pointer[-1 - oparg];
             callable = stack_pointer[-2 - oparg];
+            args = &stack_pointer[-oparg];
             if (PyStackRef_TYPE(callable) == &PyMethod_Type && PyStackRef_IsNull(self_or_null)) {
                 PyObject *callable_o = PyStackRef_AsPyObjectBorrow(callable);
                 PyObject *self = ((PyMethodObject *)callable_o)->im_self;
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index 3c643f6..ff8c4ea 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -610,11 +610,19 @@
                 for (int _i = oparg; --_i >= 0;) {
                     PyStackRef_CLOSE(values[_i]);
                 }
-                if (true) { stack_pointer += -oparg; goto error; }
+                if (true) {
+                    stack_pointer += -oparg;
+                    assert(WITHIN_STACK_BOUNDS());
+                    goto error;
+                }
             }
             PyObject *list_o = _PyList_FromArraySteal(values_o, oparg);
             STACKREFS_TO_PYOBJECTS_CLEANUP(values_o);
-            if (list_o == NULL) { stack_pointer += -oparg; goto error; }
+            if (list_o == NULL) {
+                stack_pointer += -oparg;
+                assert(WITHIN_STACK_BOUNDS());
+                goto error;
+            }
             list = PyStackRef_FromPyObjectSteal(list_o);
             stack_pointer[-oparg] = list;
             stack_pointer += 1 - oparg;
@@ -634,7 +642,11 @@
                 for (int _i = oparg*2; --_i >= 0;) {
                     PyStackRef_CLOSE(values[_i]);
                 }
-                if (true) { stack_pointer += -oparg*2; goto error; }
+                if (true) {
+                    stack_pointer += -oparg*2;
+                    assert(WITHIN_STACK_BOUNDS());
+                    goto error;
+                }
             }
             PyObject *map_o = _PyDict_FromItems(
                 values_o, 2,
@@ -644,7 +656,11 @@
             for (int _i = oparg*2; --_i >= 0;) {
                 PyStackRef_CLOSE(values[_i]);
             }
-            if (map_o == NULL) { stack_pointer += -oparg*2; goto error; }
+            if (map_o == NULL) {
+                stack_pointer += -oparg*2;
+                assert(WITHIN_STACK_BOUNDS());
+                goto error;
+            }
             map = PyStackRef_FromPyObjectSteal(map_o);
             stack_pointer[-oparg*2] = map;
             stack_pointer += 1 - oparg*2;
@@ -664,7 +680,11 @@
                 for (int _i = oparg; --_i >= 0;) {
                     PyStackRef_CLOSE(values[_i]);
                 }
-                if (true) { stack_pointer += -oparg; goto error; }
+                if (true) {
+                    stack_pointer += -oparg;
+                    assert(WITHIN_STACK_BOUNDS());
+                    goto error;
+                }
             }
             int err = 0;
             for (int i = 0; i < oparg; i++) {
@@ -676,7 +696,11 @@
             }
             if (err != 0) {
                 Py_DECREF(set_o);
-                if (true) { stack_pointer += -oparg; goto error; }
+                if (true) {
+                    stack_pointer += -oparg;
+                    assert(WITHIN_STACK_BOUNDS());
+                    goto error;
+                }
             }
             set = PyStackRef_FromPyObjectSteal(set_o);
             stack_pointer[-oparg] = set;
@@ -703,7 +727,11 @@
             PyStackRef_CLOSE(start);
             PyStackRef_CLOSE(stop);
             PyStackRef_XCLOSE(step);
-            if (slice_o == NULL) { stack_pointer += -2 - ((oparg == 3) ? 1 : 0); goto error; }
+            if (slice_o == NULL) {
+                stack_pointer += -2 - ((oparg == 3) ? 1 : 0);
+                assert(WITHIN_STACK_BOUNDS());
+                goto error;
+            }
             slice = PyStackRef_FromPyObjectSteal(slice_o);
             stack_pointer[-2 - ((oparg == 3) ? 1 : 0)] = slice;
             stack_pointer += -1 - ((oparg == 3) ? 1 : 0);
@@ -723,14 +751,22 @@
                 for (int _i = oparg; --_i >= 0;) {
                     PyStackRef_CLOSE(pieces[_i]);
                 }
-                if (true) { stack_pointer += -oparg; goto error; }
+                if (true) {
+                    stack_pointer += -oparg;
+                    assert(WITHIN_STACK_BOUNDS());
+                    goto error;
+                }
             }
             PyObject *str_o = _PyUnicode_JoinArray(&_Py_STR(empty), pieces_o, oparg);
             STACKREFS_TO_PYOBJECTS_CLEANUP(pieces_o);
             for (int _i = oparg; --_i >= 0;) {
                 PyStackRef_CLOSE(pieces[_i]);
             }
-            if (str_o == NULL) { stack_pointer += -oparg; goto error; }
+            if (str_o == NULL) {
+                stack_pointer += -oparg;
+                assert(WITHIN_STACK_BOUNDS());
+                goto error;
+            }
             str = PyStackRef_FromPyObjectSteal(str_o);
             stack_pointer[-oparg] = str;
             stack_pointer += 1 - oparg;
@@ -746,7 +782,11 @@
             _PyStackRef tup;
             values = &stack_pointer[-oparg];
             PyObject *tup_o = _PyTuple_FromStackRefSteal(values, oparg);
-            if (tup_o == NULL) { stack_pointer += -oparg; goto error; }
+            if (tup_o == NULL) {
+                stack_pointer += -oparg;
+                assert(WITHIN_STACK_BOUNDS());
+                goto error;
+            }
             tup = PyStackRef_FromPyObjectSteal(tup_o);
             stack_pointer[-oparg] = tup;
             stack_pointer += 1 - oparg;
@@ -780,7 +820,6 @@
             self_or_null = stack_pointer[-1 - oparg];
             callable = stack_pointer[-2 - oparg];
             {
-                args = &stack_pointer[-oparg];
                 uint16_t counter = read_u16(&this_instr[1].cache);
                 (void)counter;
                 #if ENABLE_SPECIALIZATION
@@ -795,7 +834,9 @@
             }
             /* Skip 2 cache entries */
             // _MAYBE_EXPAND_METHOD
+            args = &stack_pointer[-oparg];
             {
+                args = &stack_pointer[-oparg];
                 if (PyStackRef_TYPE(callable) == &PyMethod_Type && PyStackRef_IsNull(self_or_null)) {
                     PyObject *callable_o = PyStackRef_AsPyObjectBorrow(callable);
                     PyObject *self = ((PyMethodObject *)callable_o)->im_self;
@@ -813,6 +854,7 @@
                 }
             }
             // _DO_CALL
+            args = &stack_pointer[-oparg];
             self_or_null = maybe_self;
             callable = func;
             {
@@ -852,7 +894,11 @@
                     for (int _i = oparg; --_i >= 0;) {
                         PyStackRef_CLOSE(args[_i]);
                     }
-                    if (true) { stack_pointer += -2 - oparg; goto error; }
+                    if (true) {
+                        stack_pointer += -2 - oparg;
+                        assert(WITHIN_STACK_BOUNDS());
+                        goto error;
+                    }
                 }
                 PyObject *res_o = PyObject_Vectorcall(
                     callable_o, args_o,
@@ -881,7 +927,11 @@
                 for (int i = 0; i < total_args; i++) {
                     PyStackRef_CLOSE(args[i]);
                 }
-                if (res_o == NULL) { stack_pointer += -2 - oparg; goto error; }
+                if (res_o == NULL) {
+                    stack_pointer += -2 - oparg;
+                    assert(WITHIN_STACK_BOUNDS());
+                    goto error;
+                }
                 res = PyStackRef_FromPyObjectSteal(res_o);
             }
             // _CHECK_PERIODIC
@@ -1190,7 +1240,11 @@
                     for (int _i = oparg; --_i >= 0;) {
                         PyStackRef_CLOSE(args[_i]);
                     }
-                    if (true) { stack_pointer += -2 - oparg; goto error; }
+                    if (true) {
+                        stack_pointer += -2 - oparg;
+                        assert(WITHIN_STACK_BOUNDS());
+                        goto error;
+                    }
                 }
                 PyObject *res_o = tp->tp_vectorcall((PyObject *)tp, args_o, total_args, NULL);
                 STACKREFS_TO_PYOBJECTS_CLEANUP(args_o);
@@ -1199,7 +1253,11 @@
                     PyStackRef_CLOSE(args[i]);
                 }
                 PyStackRef_CLOSE(callable);
-                if (res_o == NULL) { stack_pointer += -2 - oparg; goto error; }
+                if (res_o == NULL) {
+                    stack_pointer += -2 - oparg;
+                    assert(WITHIN_STACK_BOUNDS());
+                    goto error;
+                }
                 res = PyStackRef_FromPyObjectSteal(res_o);
             }
             // _CHECK_PERIODIC
@@ -1247,7 +1305,11 @@
                     for (int _i = oparg; --_i >= 0;) {
                         PyStackRef_CLOSE(args[_i]);
                     }
-                    if (true) { stack_pointer += -2 - oparg; goto error; }
+                    if (true) {
+                        stack_pointer += -2 - oparg;
+                        assert(WITHIN_STACK_BOUNDS());
+                        goto error;
+                    }
                 }
                 PyObject *res_o = ((PyCFunctionFast)(void(*)(void))cfunc)(
                     PyCFunction_GET_SELF(callable_o),
@@ -1260,7 +1322,11 @@
                     PyStackRef_CLOSE(args[i]);
                 }
                 PyStackRef_CLOSE(callable);
-                if (res_o == NULL) { stack_pointer += -2 - oparg; goto error; }
+                if (res_o == NULL) {
+                    stack_pointer += -2 - oparg;
+                    assert(WITHIN_STACK_BOUNDS());
+                    goto error;
+                }
                 res = PyStackRef_FromPyObjectSteal(res_o);
             }
             // _CHECK_PERIODIC
@@ -1310,7 +1376,11 @@
                     for (int _i = oparg; --_i >= 0;) {
                         PyStackRef_CLOSE(args[_i]);
                     }
-                    if (true) { stack_pointer += -2 - oparg; goto error; }
+                    if (true) {
+                        stack_pointer += -2 - oparg;
+                        assert(WITHIN_STACK_BOUNDS());
+                        goto error;
+                    }
                 }
                 PyObject *res_o = cfunc(PyCFunction_GET_SELF(callable_o), args_o, total_args, NULL);
                 STACKREFS_TO_PYOBJECTS_CLEANUP(args_o);
@@ -1320,7 +1390,11 @@
                     PyStackRef_CLOSE(args[i]);
                 }
                 PyStackRef_CLOSE(callable);
-                if (res_o == NULL) { stack_pointer += -2 - oparg; goto error; }
+                if (res_o == NULL) {
+                    stack_pointer += -2 - oparg;
+                    assert(WITHIN_STACK_BOUNDS());
+                    goto error;
+                }
                 res = PyStackRef_FromPyObjectSteal(res_o);
             }
             // _CHECK_PERIODIC
@@ -1370,7 +1444,11 @@
                 assert((res_o != NULL) ^ (_PyErr_Occurred(tstate) != NULL));
                 PyStackRef_CLOSE(arg);
                 PyStackRef_CLOSE(callable);
-                if (res_o == NULL) { stack_pointer += -2 - oparg; goto error; }
+                if (res_o == NULL) {
+                    stack_pointer += -2 - oparg;
+                    assert(WITHIN_STACK_BOUNDS());
+                    goto error;
+                }
                 res = PyStackRef_FromPyObjectSteal(res_o);
             }
             // _CHECK_PERIODIC
@@ -1467,7 +1545,11 @@
             PyStackRef_CLOSE(callargs_st);
             PyStackRef_XCLOSE(kwargs_st);
             assert(PyStackRef_AsPyObjectBorrow(PEEK(2 + (oparg & 1))) == NULL);
-            if (PyStackRef_IsNull(result)) { stack_pointer += -3 - (oparg & 1); goto error; }
+            if (PyStackRef_IsNull(result)) {
+                stack_pointer += -3 - (oparg & 1);
+                assert(WITHIN_STACK_BOUNDS());
+                goto error;
+            }
             stack_pointer[-3 - (oparg & 1)] = result;
             stack_pointer += -2 - (oparg & 1);
             assert(WITHIN_STACK_BOUNDS());
@@ -1625,7 +1707,11 @@
                     PyStackRef_CLOSE(args[_i]);
                 }
                 PyStackRef_CLOSE(kwnames);
-                if (true) { stack_pointer += -3 - oparg; goto error; }
+                if (true) {
+                    stack_pointer += -3 - oparg;
+                    assert(WITHIN_STACK_BOUNDS());
+                    goto error;
+                }
             }
             PyObject *res_o = PyObject_Vectorcall(
                 callable_o, args_o,
@@ -1655,7 +1741,11 @@
             for (int i = 0; i < total_args; i++) {
                 PyStackRef_CLOSE(args[i]);
             }
-            if (res_o == NULL) { stack_pointer += -3 - oparg; goto error; }
+            if (res_o == NULL) {
+                stack_pointer += -3 - oparg;
+                assert(WITHIN_STACK_BOUNDS());
+                goto error;
+            }
             res = PyStackRef_FromPyObjectSteal(res_o);
             stack_pointer[-3 - oparg] = res;
             stack_pointer += -2 - oparg;
@@ -1785,7 +1875,11 @@
                     for (int _i = oparg; --_i >= 0;) {
                         PyStackRef_CLOSE(args[_i]);
                     }
-                    if (true) { stack_pointer += -2 - oparg; goto error; }
+                    if (true) {
+                        stack_pointer += -2 - oparg;
+                        assert(WITHIN_STACK_BOUNDS());
+                        goto error;
+                    }
                 }
                 PyObject *res_o = cfunc(self, (args_o + 1), nargs);
                 STACKREFS_TO_PYOBJECTS_CLEANUP(args_o);
@@ -1795,7 +1889,11 @@
                     PyStackRef_CLOSE(args[i]);
                 }
                 PyStackRef_CLOSE(callable);
-                if (res_o == NULL) { stack_pointer += -2 - oparg; goto error; }
+                if (res_o == NULL) {
+                    stack_pointer += -2 - oparg;
+                    assert(WITHIN_STACK_BOUNDS());
+                    goto error;
+                }
                 res = PyStackRef_FromPyObjectSteal(res_o);
             }
             // _CHECK_PERIODIC
@@ -1848,7 +1946,11 @@
                     for (int _i = oparg; --_i >= 0;) {
                         PyStackRef_CLOSE(args[_i]);
                     }
-                    if (true) { stack_pointer += -2 - oparg; goto error; }
+                    if (true) {
+                        stack_pointer += -2 - oparg;
+                        assert(WITHIN_STACK_BOUNDS());
+                        goto error;
+                    }
                 }
                 PyObject *res_o = cfunc(self, (args_o + 1), nargs, NULL);
                 STACKREFS_TO_PYOBJECTS_CLEANUP(args_o);
@@ -1858,7 +1960,11 @@
                     PyStackRef_CLOSE(args[i]);
                 }
                 PyStackRef_CLOSE(callable);
-                if (res_o == NULL) { stack_pointer += -2 - oparg; goto error; }
+                if (res_o == NULL) {
+                    stack_pointer += -2 - oparg;
+                    assert(WITHIN_STACK_BOUNDS());
+                    goto error;
+                }
                 res = PyStackRef_FromPyObjectSteal(res_o);
             }
             // _CHECK_PERIODIC
@@ -1912,7 +2018,11 @@
                 assert((res_o != NULL) ^ (_PyErr_Occurred(tstate) != NULL));
                 PyStackRef_CLOSE(self_stackref);
                 PyStackRef_CLOSE(callable);
-                if (res_o == NULL) { stack_pointer += -2 - oparg; goto error; }
+                if (res_o == NULL) {
+                    stack_pointer += -2 - oparg;
+                    assert(WITHIN_STACK_BOUNDS());
+                    goto error;
+                }
                 res = PyStackRef_FromPyObjectSteal(res_o);
             }
             // _CHECK_PERIODIC
@@ -1969,7 +2079,11 @@
                 PyStackRef_CLOSE(self_stackref);
                 PyStackRef_CLOSE(arg_stackref);
                 PyStackRef_CLOSE(callable);
-                if (res_o == NULL) { stack_pointer += -2 - oparg; goto error; }
+                if (res_o == NULL) {
+                    stack_pointer += -2 - oparg;
+                    assert(WITHIN_STACK_BOUNDS());
+                    goto error;
+                }
                 res = PyStackRef_FromPyObjectSteal(res_o);
             }
             // _CHECK_PERIODIC
@@ -2022,7 +2136,11 @@
                     for (int _i = oparg; --_i >= 0;) {
                         PyStackRef_CLOSE(args[_i]);
                     }
-                    if (true) { stack_pointer += -2 - oparg; goto error; }
+                    if (true) {
+                        stack_pointer += -2 - oparg;
+                        assert(WITHIN_STACK_BOUNDS());
+                        goto error;
+                    }
                 }
                 PyObject *res_o = PyObject_Vectorcall(
                     callable_o, args_o,
@@ -2034,7 +2152,11 @@
                 for (int i = 0; i < total_args; i++) {
                     PyStackRef_CLOSE(args[i]);
                 }
-                if (res_o == NULL) { stack_pointer += -2 - oparg; goto error; }
+                if (res_o == NULL) {
+                    stack_pointer += -2 - oparg;
+                    assert(WITHIN_STACK_BOUNDS());
+                    goto error;
+                }
                 res = PyStackRef_FromPyObjectSteal(res_o);
             }
             // _CHECK_PERIODIC
@@ -3526,6 +3648,7 @@
             self_or_null = stack_pointer[-1 - oparg];
             callable = stack_pointer[-2 - oparg];
             {
+                args = &stack_pointer[-oparg];
                 if (PyStackRef_TYPE(callable) == &PyMethod_Type && PyStackRef_IsNull(self_or_null)) {
                     PyObject *callable_o = PyStackRef_AsPyObjectBorrow(callable);
                     PyObject *self = ((PyMethodObject *)callable_o)->im_self;
@@ -3543,6 +3666,7 @@
                 }
             }
             // _MONITOR_CALL
+            args = &stack_pointer[-oparg];
             {
                 int is_meth = !PyStackRef_IsNull(maybe_self);
                 PyObject *function = PyStackRef_AsPyObjectBorrow(func);
@@ -3563,6 +3687,7 @@
                 if (err) goto error;
             }
             // _DO_CALL
+            args = &stack_pointer[-oparg];
             self_or_null = maybe_self;
             callable = func;
             {
@@ -3602,7 +3727,11 @@
                     for (int _i = oparg; --_i >= 0;) {
                         PyStackRef_CLOSE(args[_i]);
                     }
-                    if (true) { stack_pointer += -2 - oparg; goto error; }
+                    if (true) {
+                        stack_pointer += -2 - oparg;
+                        assert(WITHIN_STACK_BOUNDS());
+                        goto error;
+                    }
                 }
                 PyObject *res_o = PyObject_Vectorcall(
                     callable_o, args_o,
@@ -3631,7 +3760,11 @@
                 for (int i = 0; i < total_args; i++) {
                     PyStackRef_CLOSE(args[i]);
                 }
-                if (res_o == NULL) { stack_pointer += -2 - oparg; goto error; }
+                if (res_o == NULL) {
+                    stack_pointer += -2 - oparg;
+                    assert(WITHIN_STACK_BOUNDS());
+                    goto error;
+                }
                 res = PyStackRef_FromPyObjectSteal(res_o);
             }
             // _CHECK_PERIODIC
@@ -5777,7 +5910,11 @@
                                  "bad RAISE_VARARGS oparg");
                 break;
             }
-            if (true) { stack_pointer += -oparg; goto error; }
+            if (true) {
+                stack_pointer += -oparg;
+                assert(WITHIN_STACK_BOUNDS());
+                goto error;
+            }
         }
 
         TARGET(RERAISE) {
@@ -6834,13 +6971,14 @@
             next_instr += 1;
             INSTRUCTION_STATS(UNPACK_EX);
             _PyStackRef seq;
+            _PyStackRef *right;
             seq = stack_pointer[-1];
-            int totalargs = 1 + (oparg & 0xFF) + (oparg >> 8);
-            _PyStackRef *top = stack_pointer + totalargs - 1;
+            right = &stack_pointer[(oparg & 0xFF)];
+            _PyStackRef *top = right + (oparg >> 8);
             int res = _PyEval_UnpackIterableStackRef(tstate, seq, oparg & 0xFF, oparg >> 8, top);
             PyStackRef_CLOSE(seq);
             if (res == 0) goto pop_1_error;
-            stack_pointer += (oparg >> 8) + (oparg & 0xFF);
+            stack_pointer += (oparg & 0xFF) + (oparg >> 8);
             assert(WITHIN_STACK_BOUNDS());
             DISPATCH();
         }
@@ -6853,6 +6991,7 @@
             _Py_CODEUNIT *this_instr = next_instr - 2;
             (void)this_instr;
             _PyStackRef seq;
+            _PyStackRef *output;
             // _SPECIALIZE_UNPACK_SEQUENCE
             seq = stack_pointer[-1];
             {
@@ -6872,7 +7011,8 @@
             }
             // _UNPACK_SEQUENCE
             {
-                _PyStackRef *top = stack_pointer + oparg - 1;
+                output = &stack_pointer[-1];
+                _PyStackRef *top = output + oparg;
                 int res = _PyEval_UnpackIterableStackRef(tstate, seq, oparg, -1, top);
                 PyStackRef_CLOSE(seq);
                 if (res == 0) goto pop_1_error;
diff --git a/Python/optimizer_cases.c.h b/Python/optimizer_cases.c.h
index 4fa40ff..b704c9e 100644
--- a/Python/optimizer_cases.c.h
+++ b/Python/optimizer_cases.c.h
@@ -753,7 +753,7 @@
             for (int i = 0; i < totalargs; i++) {
                 values[i] = sym_new_unknown(ctx);
             }
-            stack_pointer += (oparg >> 8) + (oparg & 0xFF);
+            stack_pointer += (oparg & 0xFF) + (oparg >> 8);
             assert(WITHIN_STACK_BOUNDS());
             break;
         }
@@ -1607,6 +1607,7 @@
             args = &stack_pointer[-oparg];
             self_or_null = stack_pointer[-1 - oparg];
             callable = stack_pointer[-2 - oparg];
+            args = &stack_pointer[-oparg];
             (void)callable;
             (void)self_or_null;
             (void)args;