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

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mayanksolanki393 wrote:

@dtcxzyw @RKSimon
Apologies for all the silly mistakes. This is my first PR.
I can fix the review comments by amending the original commit, right?

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