diff --git a/src/test/ui/init-large-type.rs b/src/test/ui/init-large-type.rs
index 7a3ffbb6ad7..ce905572f2a 100644
--- a/src/test/ui/init-large-type.rs
+++ b/src/test/ui/init-large-type.rs
@@ -1,3 +1,4 @@
+// compile-flags: -O
 // run-pass
 
 #![allow(unused_must_use)]