[llvm] [DemandedBits] Support non-constant shift amounts (PR #148880)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

> my transformation contains a loop and the Alive syntax doesn't permit loops

You can use a smaller integer bitwidth (e.g., i4/i8), then unroll the loop with `-src-unroll=8 -tgt-unroll=8`.


https://github.com/llvm/llvm-project/pull/148880