[all-commits] [llvm/llvm-project] 31ecef: [SystemZ] Don't create PERMUTE nodes with an undef...

[Jonas Paulsson via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 31ecef76275158c87d63772a70fbc282d025e7ab
      https://github.com/llvm/llvm-project/commit/31ecef76275158c87d63772a70fbc282d025e7ab
  Author: Jonas Paulsson <paulsson at linux.vnet.ibm.com>
  Date:   2020-05-18 (Mon, 18 May 2020)

  Changed paths:
    M llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
    A llvm/test/CodeGen/SystemZ/vec-perm-14.ll
    M llvm/test/CodeGen/SystemZ/vector-constrained-fp-intrinsics.ll

  Log Message:
  -----------
  [SystemZ] Don't create PERMUTE nodes with an undef operand.

It's better to reuse the first source value than to use an undef second
operand, because that will make more resulting VPERMs have identical operands
and therefore MachineCSE more successful.

Review: Ulrich Weigand