[llvm] [InstCombine] Fold trunc(lshr(add(shl(X, ShAmt), C), ShrAmt)) (PR #214562)

[Andreas Jonson via llvm-commits]

andjo403 wrote:

also missing generlized proof in the PR description see https://llvm.org/docs/InstCombineContributorGuide.html

https://github.com/llvm/llvm-project/pull/214562