[PATCH] D67955: [AArch64] Convert neon_ushl and neon_sshl with positive constants to VSHL.

[Florian Hahn via Phabricator via llvm-commits]

fhahn created this revision.
fhahn added reviewers: t.p.northover, samparker, dmgreen, anemet.
Herald added subscribers: hiraditya, kristof.beyls.
Herald added a project: LLVM.

I think we should be able to use shl instead of sshl and ushl for
positive constant shift values, unless I am missing something.

We already have the machinery in place to ensure we only replace
nodes, if the shift value is positive and <= the element width.

This is a generalization of an earlier patch rL372565 <https://reviews.llvm.org/rL372565>.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D67955

Files:
  llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
  llvm/test/CodeGen/AArch64/arm64-vshift.ll

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