From b37ec56952d110e82344a2337aebdbcc4d404daf Mon Sep 17 00:00:00 2001
From: Mingzhu Yan <trdthg47@gmail.com>
Date: Wed, 18 Mar 2026 11:14:05 +0000
Subject: [PATCH] gh-131798: JIT: optimize _LOAD_COMMON_CONSTANT

---
 Lib/test/test_capi/test_opt.py | 12 ++++++++++++
 Python/optimizer_bytecodes.c   |  7 +++++++
 Python/optimizer_cases.c.h     |  5 ++++-
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/Lib/test/test_capi/test_opt.py b/Lib/test/test_capi/test_opt.py
index 2a126a7b29cc73..3f1edb3f9a2db7 100644
--- a/Lib/test/test_capi/test_opt.py
+++ b/Lib/test/test_capi/test_opt.py
@@ -2832,6 +2832,18 @@ def testfunc(n):
         self.assertIn("_GUARD_TYPE_VERSION", uops)
         self.assertNotIn("_CHECK_ATTR_CLASS", uops)
 
+    def test_load_common_constant(self):
+        def testfunc(n):
+            for _ in range(n):
+                x = list(i for i in ())
+            return x
+        res, ex = self._run_with_optimizer(testfunc, TIER2_THRESHOLD)
+        self.assertEqual(res, list(()))
+        self.assertIsNotNone(ex)
+        uops = get_opnames(ex)
+        self.assertIn("_BUILD_LIST", uops)
+        self.assertNotIn("_LOAD_COMMON_CONSTANT", uops)
+
     def test_load_small_int(self):
         def testfunc(n):
             x = 0
diff --git a/Python/optimizer_bytecodes.c b/Python/optimizer_bytecodes.c
index 7ca33e9e77fb74..06ed7db4fb076e 100644
--- a/Python/optimizer_bytecodes.c
+++ b/Python/optimizer_bytecodes.c
@@ -631,6 +631,13 @@ dummy_func(void) {
         value = PyJitRef_Borrow(sym_new_const(ctx, val));
     }
 
+    op(_LOAD_COMMON_CONSTANT, (-- value)) {
+        assert(oparg < NUM_COMMON_CONSTANTS);
+        PyObject *val = _PyInterpreterState_GET()->common_consts[oparg];
+        ADD_OP(_LOAD_CONST_INLINE_BORROW, 0, (uintptr_t)val);
+        value = PyJitRef_Borrow(sym_new_const(ctx, val));
+    }
+
     op(_LOAD_SMALL_INT, (-- value)) {
         PyObject *val = PyLong_FromLong(oparg);
         assert(val);
diff --git a/Python/optimizer_cases.c.h b/Python/optimizer_cases.c.h
index df6368ca8ce011..31ab4b42d922fd 100644
--- a/Python/optimizer_cases.c.h
+++ b/Python/optimizer_cases.c.h
@@ -1435,7 +1435,10 @@
 
         case _LOAD_COMMON_CONSTANT: {
             JitOptRef value;
-            value = sym_new_not_null(ctx);
+            assert(oparg < NUM_COMMON_CONSTANTS);
+            PyObject *val = _PyInterpreterState_GET()->common_consts[oparg];
+            ADD_OP(_LOAD_CONST_INLINE_BORROW, 0, (uintptr_t)val);
+            value = PyJitRef_Borrow(sym_new_const(ctx, val));
             CHECK_STACK_BOUNDS(1);
             stack_pointer[0] = value;
             stack_pointer += 1;