https://github.com/python/cpython/commit/a059e85866adb8ccd98d216b78428eb37fa70509
commit: a059e85866adb8ccd98d216b78428eb37fa70509
branch: main
author: Wulian233 <[email protected]>
committer: Fidget-Spinner <[email protected]>
date: 2026-04-11T23:02:46+08:00
summary:
gh-131798: Add `_IS_NONE` to the JIT optimizer (GH-148369)
files:
M Lib/test/test_capi/test_opt.py
M Python/optimizer_bytecodes.c
M Python/optimizer_cases.c.h
diff --git a/Lib/test/test_capi/test_opt.py b/Lib/test/test_capi/test_opt.py
index 6d8ad8798de5e2..f11413cc625422 100644
--- a/Lib/test/test_capi/test_opt.py
+++ b/Lib/test/test_capi/test_opt.py
@@ -4662,6 +4662,24 @@ def return_true():
# v + 1 should be constant folded
self.assertNotIn("_BINARY_OP", uops)
+ def test_is_none_narrows_to_constant(self):
+ def testfunc(n):
+ value = None
+ hits = 0
+ for _ in range(n):
+ if value is None:
+ hits += 1
+ return hits
+
+ res, ex = self._run_with_optimizer(testfunc, TIER2_THRESHOLD)
+ self.assertEqual(res, TIER2_THRESHOLD)
+ self.assertIsNotNone(ex)
+ uops = get_opnames(ex)
+
+ self.assertNotIn("_IS_NONE", uops)
+ self.assertIn("_GUARD_IS_NONE_POP", uops)
+ self.assertIn("_POP_TOP_NOP", uops)
+
def test_is_false_narrows_to_constant(self):
def f(n):
def return_false():
diff --git a/Python/optimizer_bytecodes.c b/Python/optimizer_bytecodes.c
index 9b1a69649978c7..c7fe34bf785c0b 100644
--- a/Python/optimizer_bytecodes.c
+++ b/Python/optimizer_bytecodes.c
@@ -724,6 +724,16 @@ dummy_func(void) {
r = right;
}
+ op(_IS_NONE, (value -- b)) {
+ if (sym_is_const(ctx, value)) {
+ PyObject *value_o = sym_get_const(ctx, value);
+ b = sym_new_const(ctx, Py_IsNone(value_o) ? Py_True : Py_False);
+ }
+ else {
+ b = sym_new_type(ctx, &PyBool_Type);
+ }
+ }
+
op(_CONTAINS_OP, (left, right -- b, l, r)) {
b = sym_new_type(ctx, &PyBool_Type);
l = left;
diff --git a/Python/optimizer_cases.c.h b/Python/optimizer_cases.c.h
index e5c67b6cf0e333..98287e7f841761 100644
--- a/Python/optimizer_cases.c.h
+++ b/Python/optimizer_cases.c.h
@@ -3193,8 +3193,16 @@
/* _POP_JUMP_IF_TRUE is not a viable micro-op for tier 2 */
case _IS_NONE: {
+ JitOptRef value;
JitOptRef b;
- b = sym_new_not_null(ctx);
+ value = stack_pointer[-1];
+ if (sym_is_const(ctx, value)) {
+ PyObject *value_o = sym_get_const(ctx, value);
+ b = sym_new_const(ctx, Py_IsNone(value_o) ? Py_True :
Py_False);
+ }
+ else {
+ b = sym_new_type(ctx, &PyBool_Type);
+ }
stack_pointer[-1] = b;
break;
}
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