[MIR] Avoid some code generation for stores of ZST

Fixes #30831

1 files changed, 27 insertions, 0 deletions

diff --git a/src/test/codegen/mir_zst_stores.rs b/src/test/codegen/mir_zst_stores.rs
new file mode 100644
index 00000000000..c1acdaf7031
--- /dev/null
+++ b/src/test/codegen/mir_zst_stores.rs
@@ -0,0 +1,27 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// compile-flags: -C no-prepopulate-passes
+
+#![feature(rustc_attrs)]
+#![crate_type = "lib"]
+use std::marker::PhantomData;
+
+
+struct Zst { phantom: PhantomData<Zst> }
+
+// CHECK-LABEL: @mir
+#[no_mangle]
+#[rustc_mir]
+fn mir(){
+    // CHECK-NOT: getelementptr
+    // CHECK-NOT: store{{.*}}undef
+    let x = Zst { phantom: PhantomData };
+}