diff --git a/libc/bionic/__umask_chk.cpp b/libc/bionic/__umask_chk.cpp
index ff67ed6..8fe95a2 100644
--- a/libc/bionic/__umask_chk.cpp
+++ b/libc/bionic/__umask_chk.cpp
@@ -42,7 +42,7 @@
  * greater than 0.
  */
 extern "C" mode_t __umask_chk(mode_t mode) {
-    if ((mode & 0777) != mode) {
+    if (__predict_false((mode & 0777) != mode)) {
         __fortify_chk_fail("umask called with invalid mask", 0);
     }