Auto merge of #36958 - nikomatsakis:issue-36856, r=eddyb

force `i1` booleans to `i8` when comparing

Work around LLVM bug.

cc #36856

r? @eddyb

src/test/run-pass/issue-36856.rs

@@ -0,0 +1,24 @@
+// Copyright 2012 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.
+
+// Regression test for #36856.
+
+// compile-flags:-g
+
+fn g() -> bool {
+    false
+}
+
+pub fn main() {
+    let a = !g();
+    if a != !g() {
+        panic!();
+    }
+}