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

[Hongyu Chen via llvm-commits]

XChy wrote:

> @XChy Can you share how the before/after IR for that case looks like?

@nikic Sure, see also https://gist.github.com/XChy/9fd567c44be7f5097b7edb973ef236f8.

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