[all-commits] [llvm/llvm-project] 7d5f79: [InstCombine] Handle equality comparison when floo...

[Antonio Frighetto via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 7d5f79f13b498ba19ae257d75a726e354a076ed9
      https://github.com/llvm/llvm-project/commit/7d5f79f13b498ba19ae257d75a726e354a076ed9
  Author: Antonio Frighetto <me at antoniofrighetto.com>
  Date:   2023-11-30 (Thu, 30 Nov 2023)

  Changed paths:
    M llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
    M llvm/test/Transforms/InstCombine/add.ll

  Log Message:
  -----------
  [InstCombine] Handle equality comparison when flooring by constant 2

Support `icmp eq` when reducing signed divisions by power of 2 to
arithmetic shift right, as `icmp ugt` may have been canonicalized
into `icmp eq` by the time additions are folded into `ashr`.

Fixes: https://github.com/llvm/llvm-project/issues/73622.

Proof: https://alive2.llvm.org/ce/z/8-eUdb.