[PATCH] D109283: [InstCombine] ror/rol(X, RotAmt) == C --> X == rol/ror(C, RotAmt) (PR51567)

[Dávid Bolvanský via Phabricator via llvm-commits]

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  ----------------------------------------
  define i1 @src(i32 %0) {
  %1:
    %2 = fshl i32 %0, i32 %0, i32 25
    %3 = icmp eq i32 %2, 5
    ret i1 %3
  }
  =>
  define i1 @tgt(i32 %0) {
  %1:
    %2 = icmp eq i32 %0, 640
    ret i1 %2
  }
  Transformation seems to be correct!

https://alive2.llvm.org/ce/z/GdY8Jm

Solves PR51567


https://reviews.llvm.org/D109283

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

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