Auto merge of rust-lang#34241 - dsprenkels:issue-32031-test, r=eddyb

add a test case for issue rust-lang#32031

I propose a test case to finish the fix for issue rust-lang#32031. Please review this commit thoroughly, as I have never written a codegen test before.

r? @eddyb

Author: bors

src/test/codegen/issue-32031.rs

@@ -0,0 +1,33 @@
+// 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
+
+#![crate_type = "lib"]
+
+#[no_mangle]
+pub struct F32(f32);
+
+// CHECK: define float @add_newtype_f32(float, float)
+#[inline(never)]
+#[no_mangle]
+pub fn add_newtype_f32(a: F32, b: F32) -> F32 {
+    F32(a.0 + b.0)
+}
+
+#[no_mangle]
+pub struct F64(f64);
+
+// CHECK: define double @add_newtype_f64(double, double)
+#[inline(never)]
+#[no_mangle]
+pub fn add_newtype_f64(a: F64, b: F64) -> F64 {
+    F64(a.0 + b.0)
+}