[clang] [llvm] [SimplifyCFG] Merge compatible noreturn calls terminating in unreachable (PR #214799)

[Nikita Popov via cfe-commits]

nikic wrote:

Yeah, this was attempted a few times in the past, and never was as profitable in practice as one would expect it to be. A lot of things have changed in the meantime, so it's probably worth another try, but the impact needs to be evaluated.

https://github.com/llvm/llvm-project/pull/214799