Yingwei Zheng 45be680b1a [SimplifyCFG] Emit rotl directly in ReduceSwitchRange (#77603) ...

This patch emits `ROTL(Cond, BitWidth - Shift)` directly in
`ReduceSwitchRange`. This should give better codegen because
`SimplifyDemandedBits` will break the rotation patterns in the original
form.

See also https://github.com/llvm/llvm-project/pull/73441 and the IR diff
https://github.com/dtcxzyw/llvm-opt-benchmark/pull/115/files.
This patch should cover most of cases handled by #73441.

2024-01-10 22:57:17 +08:00

8.9 KiB

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