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diff --git a/src/test/ui/extern/issue-64655-allow-unwind-when-calling-panic-directly.rs b/src/test/ui/extern/issue-64655-allow-unwind-when-calling-panic-directly.rs
new file mode 100644
index 000000000..7a91cbdc2
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+++ b/src/test/ui/extern/issue-64655-allow-unwind-when-calling-panic-directly.rs
@@ -0,0 +1,65 @@
+// run-pass
+// needs-unwind
+// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten no threads support
+
+// rust-lang/rust#64655: with panic=unwind, a panic from a subroutine
+// should still run destructors as it unwinds the stack. However,
+// bugs with how the nounwind LLVM attribute was applied led to this
+// simple case being mishandled *if* you had fat LTO turned on.
+
+// Unlike issue-64655-extern-rust-must-allow-unwind.rs, the issue
+// embodied in this test cropped up regardless of optimization level.
+// Therefore it seemed worthy of being enshrined as a dedicated unit
+// test.
+
+// LTO settings cannot be combined with -C prefer-dynamic
+// no-prefer-dynamic
+
+// The revisions just enumerate lto settings (the opt-level appeared irrelevant in practice)
+
+// revisions: no thin fat
+//[no]compile-flags: -C lto=no
+//[thin]compile-flags: -C lto=thin
+//[fat]compile-flags: -C lto=fat
+
+#![feature(core_panic)]
+
+// (For some reason, reproducing the LTO issue requires pulling in std
+// explicitly this way.)
+#![no_std]
+extern crate std;
+
+fn main() {
+    use std::sync::atomic::{AtomicUsize, Ordering};
+    use std::boxed::Box;
+
+    static SHARED: AtomicUsize = AtomicUsize::new(0);
+
+    assert_eq!(SHARED.fetch_add(0, Ordering::SeqCst), 0);
+
+    let old_hook = std::panic::take_hook();
+
+    std::panic::set_hook(Box::new(|_| { } )); // no-op on panic.
+
+    let handle = std::thread::spawn(|| {
+        struct Droppable;
+        impl Drop for Droppable {
+            fn drop(&mut self) {
+                SHARED.fetch_add(1, Ordering::SeqCst);
+            }
+        }
+
+        let _guard = Droppable;
+        core::panicking::panic("???");
+    });
+
+    let wait = handle.join();
+
+    // Reinstate handler to ease observation of assertion failures.
+    std::panic::set_hook(old_hook);
+
+    assert!(wait.is_err());
+
+    assert_eq!(SHARED.fetch_add(0, Ordering::SeqCst), 1);
+}