Merging upstream version 1.68.2+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 32 insertions, 0 deletions

diff --git a/tests/codegen/issue-77812.rs b/tests/codegen/issue-77812.rs
new file mode 100644
index 000000000..4cc824145
--- /dev/null
+++ b/tests/codegen/issue-77812.rs
@@ -0,0 +1,32 @@
+// compile-flags: -O
+#![crate_type = "lib"]
+
+// Test that LLVM can eliminate the unreachable `Variant::Zero` branch.
+
+#[derive(Copy, Clone, Eq, PartialEq)]
+pub enum Variant {
+    Zero,
+    One,
+    Two,
+}
+
+extern {
+    fn exf1();
+    fn exf2();
+}
+
+pub static mut GLOBAL: Variant = Variant::Zero;
+
+// CHECK-LABEL: @issue_77812
+#[no_mangle]
+pub unsafe fn issue_77812() {
+    let g = GLOBAL;
+    if g != Variant::Zero {
+        match g {
+            Variant::One => exf1(),
+            Variant::Two => exf2(),
+            // CHECK-NOT: panic
+            Variant::Zero => panic!(),
+        }
+    }
+}