[llvm] [DFAJumpThreading] Enable DFAJumpThread by default. (PR #157646)

[Nikita Popov via llvm-commits]

nikic wrote:

Would it make sense to limit the number of phi nodes?

Looking at this example, I'm also somewhat surprised that we perform the optimization in a case where the result still has multiple large dispatch switches -- is that expected/profitable?

https://github.com/llvm/llvm-project/pull/157646