[all-commits] [llvm/llvm-project] 9ab99f: [X86] Twist shuffle mask when fold HOP(SHUFFLE(X, Y...

[Pengfei Wang via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 9ab99f773fec7da4183495a3fdc655a797d3bea2
      https://github.com/llvm/llvm-project/commit/9ab99f773fec7da4183495a3fdc655a797d3bea2
  Author: Wang, Pengfei <pengfei.wang at intel.com>
  Date:   2021-07-05 (Mon, 05 Jul 2021)

  Changed paths:
    M llvm/lib/Target/X86/X86ISelLowering.cpp
    M llvm/test/CodeGen/X86/haddsub-undef.ll
    M llvm/test/CodeGen/X86/packss.ll
    A llvm/test/CodeGen/X86/pr50823.ll

  Log Message:
  -----------
  [X86] Twist shuffle mask when fold HOP(SHUFFLE(X,Y),SHUFFLE(X,Y)) -> SHUFFLE(HOP(X,Y))

This patch fixes PR50823.

The shuffle mask should be twisted twice before gotten the correct one due to the difference between inner HOP and outer.

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D104903