pythonGH-115802: Reduce the size of _INIT_CALL_PY_EXACT_ARGS. (pythonGH-116856)

Author: markshannon

Python/bytecodes.c

@@ -3150,16 +3150,14 @@ dummy_func(
         }
 
         replicate(5) pure op(_INIT_CALL_PY_EXACT_ARGS, (callable, self_or_null, args[oparg] -- new_frame: _PyInterpreterFrame*)) {
-            int argcount = oparg;
-            if (self_or_null != NULL) {
-                args--;
-                argcount++;
-            }
+            int has_self = (self_or_null != NULL);
             STAT_INC(CALL, hit);
             PyFunctionObject *func = (PyFunctionObject *)callable;
-            new_frame = _PyFrame_PushUnchecked(tstate, func, argcount);
-            for (int i = 0; i < argcount; i++) {
-                new_frame->localsplus[i] = args[i];
+            new_frame = _PyFrame_PushUnchecked(tstate, func, oparg + has_self);
+            PyObject **first_non_self_local = new_frame->localsplus + has_self;
+            new_frame->localsplus[0] = self_or_null;
+            for (int i = 0; i < oparg; i++) {
+                first_non_self_local[i] = args[i];
             }
         }