[all-commits] [llvm/llvm-project] 4ceade: [X86] Combine concat(shufps, shufps) -> shufps(conc...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 4ceade04284500ca960f6c88b546ba076ec6a643
      https://github.com/llvm/llvm-project/commit/4ceade04284500ca960f6c88b546ba076ec6a643
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2020-03-21 (Sat, 21 Mar 2020)

  Changed paths:
    M llvm/lib/Target/X86/X86ISelLowering.cpp
    M llvm/test/CodeGen/X86/masked_store_trunc.ll
    M llvm/test/CodeGen/X86/masked_store_trunc_ssat.ll
    M llvm/test/CodeGen/X86/masked_store_trunc_usat.ll
    M llvm/test/CodeGen/X86/pr40891.ll
    M llvm/test/CodeGen/X86/vector-reduce-and-bool.ll
    M llvm/test/CodeGen/X86/vector-reduce-or-bool.ll
    M llvm/test/CodeGen/X86/vector-reduce-xor-bool.ll
    M llvm/test/CodeGen/X86/vector-trunc-math.ll
    M llvm/test/CodeGen/X86/vector-trunc-packus.ll
    M llvm/test/CodeGen/X86/vector-trunc-ssat.ll
    M llvm/test/CodeGen/X86/vector-trunc-usat.ll
    M llvm/test/CodeGen/X86/vector-trunc.ll

  Log Message:
  -----------
  [X86] Combine concat(shufps,shufps) -> shufps(concat,concat)

Now that rG18c19441d105 has improved VPERM2X128 handling, we can perform this to improve x64->x32 truncation without poor cross-lane issues.

Someday combineX86ShufflesRecursively will handle this, but we're still really bad at dealing with different vector widths.