[all-commits] [llvm/llvm-project] 564180: [DAG] MatchRotate - Add funnel shift by variable s...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 564180429818dd48f2fab970fdb42d172ebd2a5f
      https://github.com/llvm/llvm-project/commit/564180429818dd48f2fab970fdb42d172ebd2a5f
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2020-03-15 (Sun, 15 Mar 2020)

  Changed paths:
    M llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
    M llvm/test/CodeGen/AMDGPU/fshl.ll
    M llvm/test/CodeGen/AMDGPU/fshr.ll
    M llvm/test/CodeGen/X86/shift-double-x86_64.ll
    M llvm/test/CodeGen/X86/shift-double.ll

  Log Message:
  -----------
  [DAG] MatchRotate - Add funnel shift by variable support

Followup to D75114, this patch reuses the existing MatchRotate ROTL/ROTR rotation pattern code to also recognize the more general FSHL/FSHR funnel shift patterns when we have variable shift amounts, matched with MatchFunnelPosNeg which acts in an (almost) equivalent manner to MatchRotatePosNeg.