[MIR] Promote temps to alloca on multi-assignment

Fixes #31002

1 files changed, 22 insertions, 0 deletions

diff --git a/src/test/run-pass/mir_temp_promotions.rs b/src/test/run-pass/mir_temp_promotions.rs
new file mode 100644
index 00000000000..de83c1f5ee0
--- /dev/null
+++ b/src/test/run-pass/mir_temp_promotions.rs
@@ -0,0 +1,22 @@
+// 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.
+
+#![feature(rustc_attrs)]
+
+#[rustc_mir]
+fn test1(f: f32) -> bool {
+    // test that we properly promote temporaries to allocas when a temporary is assigned to
+    // multiple times (assignment is still happening once ∀ possible dataflows).
+    !(f.is_nan() || f.is_infinite())
+}
+
+fn main() {
+    assert_eq!(test1(0.0), true);
+}