Add test

Author: aisk

Lib/test/test_capi/test_opt.py

@@ -2880,6 +2880,29 @@ def testfunc(n):
         self.assertIn("_POP_TOP_NOP", uops)
         self.assertLessEqual(count_ops(ex, "_POP_TOP"), 2)
 
+    def test_binary_op_refcount_elimination(self):
+        class CustomAdder:
+            def __init__(self, val):
+                self.val = val
+            def __add__(self, other):
+                return CustomAdder(self.val + other.val)
+
+        def testfunc(n):
+            a = CustomAdder(1)
+            b = CustomAdder(2)
+            res = None
+            for _ in range(n):
+                res = a + b
+            return res.val if res else 0
+
+        res, ex = self._run_with_optimizer(testfunc, TIER2_THRESHOLD)
+        self.assertEqual(res, 3)
+        self.assertIsNotNone(ex)
+        uops = get_opnames(ex)
+        self.assertIn("_BINARY_OP", uops)
+        self.assertIn("_POP_TOP_NOP", uops)
+        self.assertLessEqual(count_ops(ex, "_POP_TOP"), 2)
+
     def test_remove_guard_for_slice_list(self):
         def f(n):
             for i in range(n):