edit a comment

neonene · neonene · commit 97cfc1454bc7 · 2024-09-17T19:14:52.000+09:00
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
@@ -5377,7 +5377,8 @@ PyType_GetBaseByToken(PyTypeObject *type, void *token, PyTypeObject **result)
     } while (0)
 
     if (result == NULL) {
-        // It is best for this PGO performance to isolate the layout check
+        // If we check the `result` only here, the subsequent branches
+        // will become trivial to optimize.
         return check_base_by_token(type, token);
     }
     if (token == NULL || !PyType_Check(type)) {

Original file line number	Diff line number	Diff line change
`@@ -5377,7 +5377,8 @@ PyType_GetBaseByToken(PyTypeObject type, void token, PyTypeObject **result)`
`5377`	`5377`	`} while (0)`
`5378`	`5378`
`5379`	`5379`	`if (result == NULL) {`
`5380`		`- // It is best for this PGO performance to isolate the layout check`
	`5380`	+ // If we check the `result` only here, the subsequent branches
	`5381`	`+ // will become trivial to optimize.`
`5381`	`5382`	`return check_base_by_token(type, token);`
`5382`	`5383`	`}`
`5383`	`5384`	`if (token == NULL \|\| !PyType_Check(type)) {`