diff --git a/src/test/codegen/dst-vtable-align-nonzero.rs b/src/test/codegen/dst-vtable-align-nonzero.rs
index 00f82885d65e..021c7b19f89f 100644
--- a/src/test/codegen/dst-vtable-align-nonzero.rs
+++ b/src/test/codegen/dst-vtable-align-nonzero.rs
@@ -1,3 +1,5 @@
+// compile-flags: -O
+
 #![crate_type = "lib"]
 
 // This test checks that we annotate alignment loads from vtables with nonzero range metadata,