Add more tests

Author: tomasr8

Lib/test/test_capi/test_opt.py

@@ -2204,6 +2204,25 @@ def testfunc(n):
         self.assertNotIn("_POP_CALL_ONE_LOAD_CONST_INLINE_BORROW", uops)
         self.assertNotIn("_POP_CALL_TWO_LOAD_CONST_INLINE_BORROW", uops)
 
+    def test_call_isinstance_tuple_unknown_length(self):
+        def testfunc(n):
+            x = 0
+            for _ in range(n):
+                # tuple with an unknown length, we only narrow to bool
+                tup = tuple(eval('(int, str)'))
+                y = isinstance(42, tup)
+                if y:
+                    x += 1
+            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("_CALL_ISINSTANCE", uops)
+        self.assertNotIn("_TO_BOOL_BOOL", uops)
+        self.assertIn("_GUARD_IS_TRUE_POP", uops)
+
     def test_call_isinstance_metaclass(self):
         class EvenNumberMeta(type):
             def __instancecheck__(self, number):

Python/optimizer_bytecodes.c

@@ -965,11 +965,10 @@ dummy_func(void) {
             // inst is not an instance of any of them.
 
             int length = sym_tuple_length(cls);
-            bool all_items_known = true;
-            PyObject *out = NULL;
-            if (length >= 0) {
-                // We cannot do anything about tuples with unknown (length == -1)
-
+            if (length != -1) {
+                // We cannot do anything about tuples with unknown length
+                bool all_items_known = true;
+                PyObject *out = NULL;
                 for (int i = 0; i < length; i++) {
                     JitOptSymbol *item = sym_tuple_getitem(ctx, cls, i);
                     if (!sym_has_type(item)) {