[PATCH] D94034: [ARM] Flatten identity shuffles through vqdmulh nodes

[Dave Green via Phabricator via llvm-commits]

dmgreen created this revision.
dmgreen added reviewers: SjoerdMeijer, samtebbs, efriedma, simon_tatham, ostannard.
Herald added subscribers: danielkiss, hiraditya, kristof.beyls.
dmgreen requested review of this revision.
Herald added a project: LLVM.

Given a shuffle(vqdmulh(shuffle, shuffle), we can flatter the shuffles out if they become an identity mask. This can come up during lane interleaving, when we do that better.


https://reviews.llvm.org/D94034

Files:
  llvm/lib/Target/ARM/ARMISelLowering.cpp
  llvm/test/CodeGen/Thumb2/mve-vqdmulh.ll

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