[PATCH] D87452: [InstCombine] matchRotate - support (uniform) constant rotation amounts (PR46895)

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon created this revision.
RKSimon added reviewers: lebedev.ri, nikic, spatel.
Herald added a subscriber: hiraditya.
Herald added a project: LLVM.
RKSimon requested review of this revision.

This patch adds handling of rotation patterns with constant shift amounts.

It required an extension of the bswap/bitreverse collectBitParts helper to peek through calls to funnel shift intrinsics - this may be additionally useful in the future if we discover the need to merge other calls (inner bswap/bitreverse?).

This fixes the easy half of PR46895 - the next bit will be how we want to support non-uniform constant vectors - does PatternMatch have any equivalent of ISD::matchBinaryPredicate ?


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D87452

Files:
  llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
  llvm/lib/Transforms/Utils/Local.cpp
  llvm/test/Transforms/InstCombine/bswap.ll
  llvm/test/Transforms/InstCombine/fsh.ll
  llvm/test/Transforms/InstCombine/or-concat.ll
  llvm/test/Transforms/InstCombine/rotate.ll

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