add test case

Author: noamcohen97

Lib/test/test_capi/test_opt.py

@@ -2094,6 +2094,19 @@ def testfunc(n):
         self.assertNotIn("_POP_CALL_TWO_LOAD_CONST_INLINE_BORROW", uops)
         self.assertNotIn("_SWAP_CALL_TWO_LOAD_CONST_INLINE_BORROW", uops)
 
+    def test_call_isinstance_guards_pop_top(self):
+        def testfunc(n):
+            x = 0
+            for _ in range(n):
+                x += isinstance(42, int)
+            return x
+
+        res, ex = self._run_with_optimizer(testfunc, TIER2_THRESHOLD)
+        self.assertEqual(res, TIER2_THRESHOLD)
+        self.assertIsNotNone(ex)
+        uops = get_opnames(ex)
+        self.assertIn("_POP_TOP_NOP", uops)
+
     def test_call_list_append(self):
         def testfunc(n):
             a = []