GH-131798: Turn _LOAD_SMALL_INT into _LOAD_CONST_INLINE_BORROW in the JIT (GH-134406)

Author: Zheaoli

Lib/test/test_capi/test_opt.py

@@ -2156,6 +2156,18 @@ def testfunc(n):
         self.assertIn("_GUARD_TYPE_VERSION", uops)
         self.assertNotIn("_CHECK_ATTR_CLASS", uops)
 
+    def test_load_small_int(self):
+        def testfunc(n):
+            x = 0
+            for i in range(n):
+                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.assertNotIn("_LOAD_SMALL_INT", uops)
+        self.assertIn("_LOAD_CONST_INLINE_BORROW", uops)
 
 def global_identity(x):
     return x

Misc/NEWS.d/next/Core_and_Builtins/2025-05-21-13-57-26.gh-issue-131798.QwS5Bb.rst

@@ -0,0 +1 @@
+JIT: replace ``_LOAD_SMALL_INT`` with ``_LOAD_CONST_INLINE_BORROW``

Python/optimizer_bytecodes.c

@@ -528,7 +528,10 @@ dummy_func(void) {
     }
 
     op(_LOAD_SMALL_INT, (-- value)) {
-        PyObject *val = PyLong_FromLong(this_instr->oparg);
+        PyObject *val = PyLong_FromLong(oparg);
+        assert(val);
+        assert(_Py_IsImmortal(val));
+        REPLACE_OP(this_instr, _LOAD_CONST_INLINE_BORROW, 0, (uintptr_t)val);
         value = sym_new_const(ctx, val);
     }