From 00818c896c07527c2cee5c773fdc7e3b2fedbe26 Mon Sep 17 00:00:00 2001
From: Kumar Aditya <kumaraditya@python.org>
Date: Tue, 7 Apr 2026 18:11:42 +0530
Subject: [PATCH 1/2] fix _BINARY_OP_SUBSCR_DICT optimization

---
 Python/optimizer_bytecodes.c | 10 +++++-----
 Python/optimizer_cases.c.h   | 10 +++++-----
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/Python/optimizer_bytecodes.c b/Python/optimizer_bytecodes.c
index 58b50707e55cee..9f0584c50bebf5 100644
--- a/Python/optimizer_bytecodes.c
+++ b/Python/optimizer_bytecodes.c
@@ -515,18 +515,18 @@ dummy_func(void) {
     }
 
     op(_BINARY_OP_SUBSCR_DICT, (dict_st, sub_st -- res, ds, ss)) {
-        PyObject *sub = sym_get_const(ctx, sub_st);
-        if (sub != NULL) {
-            optimize_dict_known_hash(ctx, dependencies, this_instr,
-                                     sub, _BINARY_OP_SUBSCR_DICT_KNOWN_HASH);
-        }
         res = sym_new_not_null(ctx);
         ds = dict_st;
         ss = sub_st;
+        PyObject *sub = sym_get_const(ctx, sub_st);
         if (sym_is_not_container(sub_st) &&
             sym_matches_type(dict_st, &PyFrozenDict_Type)) {
             REPLACE_OPCODE_IF_EVALUATES_PURE(dict_st, sub_st, res);
         }
+        else if (sub != NULL) {
+            optimize_dict_known_hash(ctx, dependencies, this_instr,
+                                     sub, _BINARY_OP_SUBSCR_DICT_KNOWN_HASH);
+        }
     }
 
     op(_BINARY_OP_SUBSCR_LIST_SLICE, (list_st, sub_st -- res, ls, ss)) {
diff --git a/Python/optimizer_cases.c.h b/Python/optimizer_cases.c.h
index 891887301119d7..bb588457d22d5c 100644
--- a/Python/optimizer_cases.c.h
+++ b/Python/optimizer_cases.c.h
@@ -1462,14 +1462,10 @@
             JitOptRef ss;
             sub_st = stack_pointer[-1];
             dict_st = stack_pointer[-2];
-            PyObject *sub = sym_get_const(ctx, sub_st);
-            if (sub != NULL) {
-                optimize_dict_known_hash(ctx, dependencies, this_instr,
-                                     sub, _BINARY_OP_SUBSCR_DICT_KNOWN_HASH);
-            }
             res = sym_new_not_null(ctx);
             ds = dict_st;
             ss = sub_st;
+            PyObject *sub = sym_get_const(ctx, sub_st);
             if (sym_is_not_container(sub_st) &&
                 sym_matches_type(dict_st, &PyFrozenDict_Type)) {
                 if (
@@ -1519,6 +1515,10 @@
                     break;
                 }
             }
+            else if (sub != NULL) {
+                optimize_dict_known_hash(ctx, dependencies, this_instr,
+                                     sub, _BINARY_OP_SUBSCR_DICT_KNOWN_HASH);
+            }
             CHECK_STACK_BOUNDS(1);
             stack_pointer[-2] = res;
             stack_pointer[-1] = ds;

From c9cd8f23e8032fcac4071e3d88a9ba5956bfad97 Mon Sep 17 00:00:00 2001
From: Kumar Aditya <kumaraditya@python.org>
Date: Tue, 7 Apr 2026 22:52:44 +0530
Subject: [PATCH 2/2] add test

---
 Lib/test/test_capi/test_opt.py | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/Lib/test/test_capi/test_opt.py b/Lib/test/test_capi/test_opt.py
index b31c9f68d01bec..6d0a0c7545ec1a 100644
--- a/Lib/test/test_capi/test_opt.py
+++ b/Lib/test/test_capi/test_opt.py
@@ -2340,6 +2340,21 @@ def testfunc(n):
         self.assertIn("_BINARY_OP_SUBSCR_DICT_KNOWN_HASH", uops)
         self.assertNotIn("_BINARY_OP_SUBSCR_DICT", uops)
 
+
+    def test_binary_op_subscr_constant_frozendict_known_hash(self):
+        def testfunc(n):
+            x = 0
+            for _ in range(n):
+                x += FROZEN_DICT_CONST['x']
+            return x
+
+        res, ex = self._run_with_optimizer(testfunc, 2 * TIER2_THRESHOLD)
+        self.assertEqual(res, 2 * TIER2_THRESHOLD)
+        self.assertIsNotNone(ex)
+        uops = get_opnames(ex)
+        self.assertNotIn("_BINARY_OP_SUBSCR_DICT_KNOWN_HASH", uops)
+        self.assertNotIn("_BINARY_OP_SUBSCR_DICT", uops)
+
     def test_store_subscr_dict_known_hash(self):
         # str, int, bytes, float, complex, tuple and any python object which has generic hash
         def testfunc(n):