[llvm] [DFAJumpThreading] Enable the pass by default (PR #83033)

[Nikita Popov via llvm-commits]

nikic wrote:

Thanks, the new compile-time numbers look a lot better!

While this mostly resolves the compile-time issues for average cases, I am still concerned about the behavior of the pass in pathological cases, in particular the discussion starting at https://github.com/llvm/llvm-project/pull/85015#issuecomment-1998028311. We need to make sure that even if all the early-exit conditions don't trigger, we never inspect an unreasonably large number of paths.

https://github.com/llvm/llvm-project/pull/83033