[all-commits] [llvm/llvm-project] e0cff3: [X86][SSE] LowerVectorAllZeroTest - add support fo...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: e0cff30c17d585a5618ce00266abf4f2fdb5d415
      https://github.com/llvm/llvm-project/commit/e0cff30c17d585a5618ce00266abf4f2fdb5d415
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2020-06-14 (Sun, 14 Jun 2020)

  Changed paths:
    M llvm/lib/Target/X86/X86ISelLowering.cpp
    M llvm/test/CodeGen/X86/pr45378.ll
    M llvm/test/CodeGen/X86/ptest.ll

  Log Message:
  -----------
  [X86][SSE] LowerVectorAllZeroTest - add support for pre-SSE41 targets

Even without PTEST, we can still efficiently perform an OR reduction as PMOVMSKB(PCMPEQB(X,0)) == 0, avoiding xmm->gpr extractions.