Add a test for rust-lang#26468

The fix for rust-lang#26468 was made upstream and landed with the LLVM update in rust-lang#27076.

Closes rust-lang#26468

src/test/run-pass/issue-26468.rs

@@ -0,0 +1,38 @@
+// Copyright 2015 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.
+
+#![allow(dead_code)]
+
+enum FooMode {
+    Check = 0x1001,
+}
+
+enum BarMode {
+    Check = 0x2001,
+}
+
+enum Mode {
+    Foo(FooMode),
+    Bar(BarMode),
+}
+
+#[inline(never)]
+fn broken(mode: &Mode) -> u32 {
+    for _ in 0..1 {
+        if let Mode::Foo(FooMode::Check) = *mode { return 17 }
+        if let Mode::Bar(BarMode::Check) = *mode { return 19 }
+    }
+    return 42;
+}
+
+fn main() {
+    let mode = Mode::Bar(BarMode::Check);
+    assert_eq!(broken(&mode), 19);
+}