[PATCH] D150091: [InstCombine] Transform `icmp eq/ne ({su}div exact X,Y),C` -> `icmp eq/ne X, Y*C`

[Noah Goldstein via Phabricator via llvm-commits]

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We can do this if `Y*C` doesn't overflow. This is trivial if `C` is
0/1. Otherwise we actually generate a `mul` instruction iff the `div`
has one use.

Alive2 Links:

  udiv: https://alive2.llvm.org/ce/z/GWPW67
  sdiv: https://alive2.llvm.org/ce/z/bUoX9h


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D150091

Files:
  llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
  llvm/test/Transforms/InstCombine/sdiv-icmp.ll

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