2 // min-llvm-version: 15.0
5 use std::mem::MaybeUninit;
7 // Boxing a `MaybeUninit` value should not copy junk from the stack
9 pub fn box_uninitialized() -> Box<MaybeUninit<usize>> {
10 // CHECK-LABEL: @box_uninitialized
15 Box::new(MaybeUninit::uninit())
18 // FIXME: add a test for a bigger box. Currently broken, see
19 // https://github.com/rust-lang/rust/issues/58201.
21 // Hide the `allocalign` attribute in the declaration of __rust_alloc
22 // from the CHECK-NOT above, and also verify the attributes got set reasonably.
23 // CHECK: declare noalias ptr @__rust_alloc(i{{[0-9]+}}, i{{[0-9]+}} allocalign) unnamed_addr [[RUST_ALLOC_ATTRS:#[0-9]+]]
25 // CHECK-DAG: attributes [[RUST_ALLOC_ATTRS]] = { {{.*}} allockind("alloc,uninitialized,aligned") allocsize(0) uwtable "alloc-family"="__rust_alloc" {{.*}} }