[all-commits] [llvm/llvm-project] c00cab: [InstCombine] add test for or-of-icmps; NFC

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  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: c00cab878aa523e20a5dbd618e9852e191504cfe
      https://github.com/llvm/llvm-project/commit/c00cab878aa523e20a5dbd618e9852e191504cfe
  Author: Sanjay Patel <spatel at rotateright.com>
  Date:   2021-10-10 (Sun, 10 Oct 2021)

  Changed paths:
    M llvm/test/Transforms/InstCombine/or.ll

  Log Message:
  -----------
  [InstCombine] add test for or-of-icmps; NFC


  Commit: da210f5d3425e8877ceabaf6ed3483d52cbd7448
      https://github.com/llvm/llvm-project/commit/da210f5d3425e8877ceabaf6ed3483d52cbd7448
  Author: Sanjay Patel <spatel at rotateright.com>
  Date:   2021-10-10 (Sun, 10 Oct 2021)

  Changed paths:
    M llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
    M llvm/test/Transforms/InstCombine/2007-12-18-AddSelCmpSub.ll
    M llvm/test/Transforms/InstCombine/icmp-sub.ll
    M llvm/test/Transforms/InstCombine/or.ll

  Log Message:
  -----------
  [InstCombine] canonicalize "(C2 - Y) > C" as (Y + ~C2) < ~C

The test diffs show that we have better analysis/folds for 'add'
(although we should at least have the simplifications
independently, so we don't have the one-use restriction).

This is related to solving regressions that would appear in
transforms related to D111410, and that is part of a series
of enhancements that may eventually helpi solve PR34047.

https://alive2.llvm.org/ce/z/3tB9KG

  define i1 @src(i8 %x, i8 %C, i8 %C2) {
    %sub = sub nuw i8 %C2, %x
    %r = icmp slt i8 %sub, %C
    ret i1 %r
  }

  define i1 @tgt(i8 %x, i8 %C, i8 %C2) {
    %Cnot = xor i8 %C, -1
    %C2not = xor i8 %C2, -1
    %add = add nuw i8 %x, %C2not
    %r = icmp sgt i8 %add, %Cnot
    ret i1 %r
  }


Compare: https://github.com/llvm/llvm-project/compare/4ead32d1cf8e...da210f5d3425