gh-148604: change ADD_OP(_POP_TOP, ...) to optimize_pop_top in optimizer_bytecodes.c

Author: NekoAsakura

Lib/test/test_capi/test_opt.py

@@ -3453,6 +3453,10 @@ def f(n):
         self.assertEqual(res, TIER2_THRESHOLD)
         uops = get_opnames(ex)
         self.assertNotIn("_LOAD_SPECIAL", uops)
+        # __enter__/__exit__ produce 2 _POP_TOP_NOP
+        # x += 1 produces 2 _POP_TOP_NOP
+        # __exit__()'s None return produces 1 _POP_TOP_NOP
+        self.assertGreaterEqual(count_ops(ex, "_POP_TOP_NOP"), 5)
 
     def test_store_fast_refcount_elimination(self):
         def foo(x):

Python/optimizer_bytecodes.c

@@ -1902,7 +1902,7 @@ dummy_func(void) {
                 ADD_OP(immortal ? _LOAD_CONST_INLINE_BORROW : _LOAD_CONST_INLINE,
                        0, (uintptr_t)descr);
                 ADD_OP(_SWAP, 3, 0);
-                ADD_OP(_POP_TOP, 0, 0);
+                optimize_pop_top(ctx, this_instr, method_and_self[0]);
                 if ((type->tp_flags & Py_TPFLAGS_IMMUTABLETYPE) == 0) {
                     PyType_Watch(TYPE_WATCHER_ID, (PyObject *)type);
                     _Py_BloomFilter_Add(dependencies, type);