[libunwind] [llvm] [MC][AArch64] Add .cfi_llvm_set_ra_sign_state for PAuth_LR (PR #205442)

[Jon Roelofs via cfe-commits]

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jroelofs wrote:

Oh, yeah, the check on line 340 is unsatisfiable. That's just completely broken.

https://github.com/llvm/llvm-project/pull/205442