test that MaybeUninit<bool> is not noundef

src/test/codegen/function-arguments.rs

@@ -3,6 +3,8 @@
 #![crate_type = "lib"]
 #![feature(rustc_attrs)]
 
+use std::mem::MaybeUninit;
+
 pub struct S {
   _field: [i32; 8],
 }
@@ -17,6 +19,12 @@ pub fn boolean(x: bool) -> bool {
   x
 }
 
+// CHECK: i8 @maybeuninit_boolean(i8 %x)
+#[no_mangle]
+pub fn maybeuninit_boolean(x: MaybeUninit<bool>) -> MaybeUninit<bool> {
+  x
+}
+
 // CHECK: @readonly_borrow(i32* noalias readonly align 4 dereferenceable(4) %_1)
 // FIXME #25759 This should also have `nocapture`
 #[no_mangle]