[llvm] [DFAJumpThreading] Early exit if switch is not in a loop (PR #85360)

[Nikita Popov via llvm-commits]

https://github.com/nikic approved this pull request.

This looks reasonable to me, but I was not able to test compile-time impact, because DFAJumpThreading causes a timeout in the stage 2 build (same as before).

https://github.com/llvm/llvm-project/pull/85360