add test for GVN issue; cleanup in dataflow_const_prop

1 files changed, 24 insertions, 0 deletions

diff --git a/tests/mir-opt/gvn_uninhabited.rs b/tests/mir-opt/gvn_uninhabited.rs
new file mode 100644
index 00000000000..a55b2dd763a
--- /dev/null
+++ b/tests/mir-opt/gvn_uninhabited.rs
@@ -0,0 +1,24 @@
+// unit-test: GVN
+// compile-flags: -O
+// EMIT_MIR_FOR_EACH_PANIC_STRATEGY
+// skip-filecheck
+
+#![feature(never_type)]
+
+#[derive(Copy, Clone)]
+pub enum E {
+    A(!, u32),
+}
+
+pub union U {
+    i: u32,
+    e: E,
+}
+
+// EMIT_MIR gvn_uninhabited.f.GVN.diff
+pub const fn f() -> u32 {
+    let E::A(_, i) = unsafe { (&U { i: 0 }).e };
+    i
+}
+
+fn main() {}