[all-commits] [llvm/llvm-project] 80dee7: [X86][SSE] Fold unpack(hop(), hop()) -> permute(hop())

[Simon Pilgrim via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 80dee7965dffdfb866afa9d74f3a4a97453708b2
      https://github.com/llvm/llvm-project/commit/80dee7965dffdfb866afa9d74f3a4a97453708b2
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2021-01-08 (Fri, 08 Jan 2021)

  Changed paths:
    M llvm/lib/Target/X86/X86ISelLowering.cpp
    M llvm/test/CodeGen/X86/horizontal-shuffle-2.ll

  Log Message:
  -----------
  [X86][SSE] Fold unpack(hop(),hop()) -> permute(hop())

UNPCKL/UNPCKH only uses one op from each hop, so we can merge the hops and then permute the result.