[llvm] [InstCombine] Combine trunc (lshr X, BW-1) to i1 --> icmp slt X, 0 (#142593) (PR #143846)

[Simon Pilgrim via llvm-commits]

RKSimon wrote:

sure - better to push additional commits to the branch instead of rebasing if you can

https://github.com/llvm/llvm-project/pull/143846