GH-116468: Use constants instead of oparg in stack effects when oparg is known to be a constant. (GH-116469)

Author: markshannon

Include/internal/pycore_opcode_metadata.h

@@ -129,6 +129,8 @@ dummy_func(
     PyObject *top;
     PyObject *type;
     PyObject *typevars;
+    PyObject *val0;
+    PyObject *val1;
     int values_or_none;
 
     switch (opcode) {
@@ -1223,13 +1225,13 @@ dummy_func(
 
         macro(UNPACK_SEQUENCE) = _SPECIALIZE_UNPACK_SEQUENCE + _UNPACK_SEQUENCE;
 
-        inst(UNPACK_SEQUENCE_TWO_TUPLE, (unused/1, seq -- values[oparg])) {
+        inst(UNPACK_SEQUENCE_TWO_TUPLE, (unused/1, seq -- val1, val0)) {
+            assert(oparg == 2);
             DEOPT_IF(!PyTuple_CheckExact(seq));
             DEOPT_IF(PyTuple_GET_SIZE(seq) != 2);
-            assert(oparg == 2);
             STAT_INC(UNPACK_SEQUENCE, hit);
-            values[0] = Py_NewRef(PyTuple_GET_ITEM(seq, 1));
-            values[1] = Py_NewRef(PyTuple_GET_ITEM(seq, 0));
+            val0 = Py_NewRef(PyTuple_GET_ITEM(seq, 0));
+            val1 = Py_NewRef(PyTuple_GET_ITEM(seq, 1));
             DECREF_INPUTS();
         }
 
@@ -3236,39 +3238,33 @@ dummy_func(
             DISPATCH_INLINED(new_frame);
         }
 
-        inst(CALL_TYPE_1, (unused/1, unused/2, callable, null, args[oparg] -- res)) {
+        inst(CALL_TYPE_1, (unused/1, unused/2, callable, null, arg -- res)) {
             assert(oparg == 1);
             DEOPT_IF(null != NULL);
-            PyObject *obj = args[0];
             DEOPT_IF(callable != (PyObject *)&PyType_Type);
             STAT_INC(CALL, hit);
-            res = Py_NewRef(Py_TYPE(obj));
-            Py_DECREF(obj);
-            Py_DECREF(&PyType_Type);  // I.e., callable
+            res = Py_NewRef(Py_TYPE(arg));
+            Py_DECREF(arg);
         }
 
-        inst(CALL_STR_1, (unused/1, unused/2, callable, null, args[oparg] -- res)) {
+        inst(CALL_STR_1, (unused/1, unused/2, callable, null, arg -- res)) {
             assert(oparg == 1);
             DEOPT_IF(null != NULL);
             DEOPT_IF(callable != (PyObject *)&PyUnicode_Type);
             STAT_INC(CALL, hit);
-            PyObject *arg = args[0];
             res = PyObject_Str(arg);
             Py_DECREF(arg);
-            Py_DECREF(&PyUnicode_Type);  // I.e., callable
             ERROR_IF(res == NULL, error);
             CHECK_EVAL_BREAKER();
         }
 
-        inst(CALL_TUPLE_1, (unused/1, unused/2, callable, null, args[oparg] -- res)) {
+        inst(CALL_TUPLE_1, (unused/1, unused/2, callable, null, arg -- res)) {
             assert(oparg == 1);
             DEOPT_IF(null != NULL);
             DEOPT_IF(callable != (PyObject *)&PyTuple_Type);
             STAT_INC(CALL, hit);
-            PyObject *arg = args[0];
             res = PySequence_Tuple(arg);
             Py_DECREF(arg);
-            Py_DECREF(&PyTuple_Type);  // I.e., tuple
             ERROR_IF(res == NULL, error);
             CHECK_EVAL_BREAKER();
         }
@@ -3490,14 +3486,14 @@ dummy_func(
         }
 
         // This is secretly a super-instruction
-        tier1 inst(CALL_LIST_APPEND, (unused/1, unused/2, callable, self, args[oparg] -- unused)) {
+        tier1 inst(CALL_LIST_APPEND, (unused/1, unused/2, callable, self, arg -- unused)) {
             assert(oparg == 1);
             PyInterpreterState *interp = tstate->interp;
             DEOPT_IF(callable != interp->callable_cache.list_append);
             assert(self != NULL);
             DEOPT_IF(!PyList_Check(self));
             STAT_INC(CALL, hit);
-            if (_PyList_AppendTakeRef((PyListObject *)self, args[0]) < 0) {
+            if (_PyList_AppendTakeRef((PyListObject *)self, arg) < 0) {
                 goto pop_1_error;  // Since arg is DECREF'ed already
             }
             Py_DECREF(self);