llvm/llvm-project

[AArch64] Add SimplifyDemandedVectorEltsForTargetNode support for AArch64ISD::DUPLANE nodes

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#87,497 opened on 2024年4月3日

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説明

Noticed on #86284 - aarch64 is missing SimplifyDemandedVectorElts handling to/from AArch64ISD::DUPLANE nodes

  • Extend performDUPCombine to call SimplifyDemandedVectorElts from AArch64ISD::DUPLANE nodes as we only demand that one lane element.
  • Add AArch64TargetLowering::SimplifyDemandedVectorEltsForTargetNode to handle AArch64ISD::DUPLANE nodes (and AArch64ISD::DUP?) - if we only demand the dup lane index we might be able to remove the node entirely.
  • The hadd-combine.ll tests might be enough, but we could require some additional test coverage.

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