[all-commits] [llvm/llvm-project] 47cea9: Revert rG66e7dce714fab "Revert "[X86][SSE] Shuffle...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 47cea9e82dda941e49a2d9cc11f0414436336d46
      https://github.com/llvm/llvm-project/commit/47cea9e82dda941e49a2d9cc11f0414436336d46
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2020-08-04 (Tue, 04 Aug 2020)

  Changed paths:
    M llvm/lib/Target/X86/X86ISelLowering.cpp
    M llvm/test/CodeGen/X86/insertelement-ones.ll
    M llvm/test/CodeGen/X86/shuffle-vs-trunc-256.ll
    M llvm/test/CodeGen/X86/vector-shuffle-128-v8.ll
    M llvm/test/CodeGen/X86/vector-shuffle-256-v32.ll

  Log Message:
  -----------
  Revert rG66e7dce714fab "Revert "[X86][SSE] Shuffle combine blends to OR(X,Y) if the relevant elements are known zero.""

[X86][SSE] Shuffle combine blends to OR(X,Y) if the relevant elements are known zero (REAPPLIED)

This allows us to remove the (depth violating) code in getFauxShuffleMask where we were combining the OR(SHUFFLE,SHUFFLE) shuffle inputs as well, and not just the OR().

This is a minor step toward being able to shuffle combine from/to SELECT/BLENDV as a faux shuffle.

Reapplied with fixed signed/unsigned comparisons.