1 files changed, 32 insertions, 0 deletions
diff --git a/tests/mir-opt/early_otherwise_branch_soundness.rs b/tests/mir-opt/early_otherwise_branch_soundness.rs
new file mode 100644
index 000000000..cd4589232
--- /dev/null
+++ b/tests/mir-opt/early_otherwise_branch_soundness.rs
@@ -0,0 +1,32 @@
+// unit-test: EarlyOtherwiseBranch
+
+// Tests various cases that the `early_otherwise_branch` opt should *not* optimize
+
+// From #78496
+enum E<'a> {
+    Empty,
+    Some(&'a E<'a>),
+}
+
+// EMIT_MIR early_otherwise_branch_soundness.no_downcast.EarlyOtherwiseBranch.diff
+fn no_downcast(e: &E) -> u32 {
+    if let E::Some(E::Some(_)) = e { 1 } else { 2 }
+}
+
+// SAFETY: if `a` is `Some`, `b` must point to a valid, initialized value
+// EMIT_MIR early_otherwise_branch_soundness.no_deref_ptr.EarlyOtherwiseBranch.diff
+unsafe fn no_deref_ptr(a: Option<i32>, b: *const Option<i32>) -> i32 {
+    match a {
+        // `*b` being correct depends on `a == Some(_)`
+        Some(_) => match *b {
+            Some(v) => v,
+            _ => 0,
+        },
+        _ => 0,
+    }
+}
+
+fn main() {
+    no_downcast(&E::Empty);
+    unsafe { no_deref_ptr(None, std::ptr::null()) };
+}