python · Fidget-Spinner · Dec 14, 2025 · Jun 28, 2025 · Jun 28, 2025 · Dec 11, 2025
diff --git a/Include/internal/pycore_opcode_metadata.h b/Include/internal/pycore_opcode_metadata.h
diff --git a/Include/internal/pycore_uop_ids.h b/Include/internal/pycore_uop_ids.h
diff --git a/Include/internal/pycore_uop_metadata.h b/Include/internal/pycore_uop_metadata.h
diff --git a/Lib/test/test_capi/test_opt.py b/Lib/test/test_capi/test_opt.py
@@ -1957,6 +1957,20 @@ def testfunc(n):
        self.assertNotIn("_GUARD_NOS_NULL", uops)
        self.assertNotIn("_GUARD_CALLABLE_STR_1", uops)

+    def test_call_str_1_pop_top(self):
+        def testfunc(n):
+            x = 0
+            for _ in range(n):
+                t = str("")
+                x += 1 if len(t) == 0 else 0
+            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_STR_1", uops)
+        self.assertIn("_POP_TOP_NOP", uops)
+
    def test_call_str_1_result_is_str(self):
        def testfunc(n):
            x = 0

diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2025-06-28-17-54-27.gh-issue-134584.EXgPub.rst b/Misc/NEWS.d/next/Core_and_Builtins/2025-06-28-17-54-27.gh-issue-134584.EXgPub.rst
@@ -0,0 +1 @@
+Eliminate redundant refcounting from ``_CALL_STR_1``.
@@ -4040,18 +4040,17 @@ dummy_func(
            DEOPT_IF(callable_o != (PyObject *)&PyUnicode_Type);
        }

-        op(_CALL_STR_1, (callable, null, arg -- res)) {
+        op(_CALL_STR_1, (callable, null, arg -- res, a)) {
            PyObject *arg_o = PyStackRef_AsPyObjectBorrow(arg);

            assert(oparg == 1);
            STAT_INC(CALL, hit);
            PyObject *res_o = PyObject_Str(arg_o);
-            DEAD(null);
-            DEAD(callable);
-            (void)callable; // Silence compiler warnings about unused variables
-            (void)null;
-            PyStackRef_CLOSE(arg);
-            ERROR_IF(res_o == NULL);
+            if (res_o == NULL) {
+                ERROR_NO_POP();
+            }
+            a = arg;
+            INPUTS_DEAD();
            res = PyStackRef_FromPyObjectSteal(res_o);
        }

@@ -4061,6 +4060,7 @@ dummy_func(
            _GUARD_NOS_NULL +
            _GUARD_CALLABLE_STR_1 +
            _CALL_STR_1 +
+            POP_TOP +
            _CHECK_PERIODIC_AT_END;

        op(_GUARD_CALLABLE_TUPLE_1, (callable, unused, unused -- callable, unused, unused)) {

diff --git a/Python/executor_cases.c.h b/Python/executor_cases.c.h
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
@@ -951,7 +951,7 @@ dummy_func(void) {
        }
    }

-    op(_CALL_STR_1, (unused, unused, arg -- res)) {
+    op(_CALL_STR_1, (unused, unused, arg -- res, a)) {
        if (sym_matches_type(arg, &PyUnicode_Type)) {
            // e.g. str('foo') or str(foo) where foo is known to be a string
            // Note: we must strip the reference information because it goes
@@ -961,6 +961,7 @@ dummy_func(void) {
        else {
            res = sym_new_type(ctx, &PyUnicode_Type);
        }
+        a = arg;
    }

    op(_CALL_ISINSTANCE, (unused, unused, instance, cls -- res)) {

diff --git a/Python/optimizer_cases.c.h b/Python/optimizer_cases.c.h
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		Eliminate redundant refcounting from ``_CALL_STR_1``.