[PATCH] D122485: [SimplifyCFG] Fold mutil cases to And mask

[chenglin.bi via Phabricator via llvm-commits]

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When switch with 2^n cases go to one result, check if the 2^n cases can be covered by n bit masks.
If yes we can use "and condition, ~mask" to simplify the switch

Fix one case of https://github.com/llvm/llvm-project/issues/39957


https://reviews.llvm.org/D122485

Files:
  llvm/lib/Transforms/Utils/SimplifyCFG.cpp
  llvm/test/Transforms/SimplifyCFG/switch-to-select-two-case.ll

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