gh-131798: JIT: optimize _LOAD_COMMON_CONSTANT

Author: trdthg

Lib/test/test_capi/test_opt.py

@@ -2832,6 +2832,25 @@ def testfunc(n):
         self.assertIn("_GUARD_TYPE_VERSION", uops)
         self.assertNotIn("_CHECK_ATTR_CLASS", uops)
 
+    def test_load_common_constant(self):
+        def testfunc(n):
+            x = 0
+            for _ in range(n):
+                y = list(i for i in (1, 2, 3))
+                if len(y) == 3:
+                    x += 1
+            return x
+        res = testfunc(TIER2_THRESHOLD)
+        self.assertEqual(res, TIER2_THRESHOLD)
+        executors = get_all_executors(testfunc)
+        uops = [
+            opname
+            for executor in executors
+            for opname in get_opnames(executor)
+        ]
+        self.assertIn("_BUILD_LIST", uops)
+        self.assertNotIn("_LOAD_COMMON_CONSTANT", uops)
+
     def test_load_small_int(self):
         def testfunc(n):
             x = 0

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);