[all-commits] [llvm/llvm-project] 91ebc4: [ARM] VMOVN undef folding

[David Green via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 91ebc4e864c061f9a72791700150f82d19bbd003
      https://github.com/llvm/llvm-project/commit/91ebc4e864c061f9a72791700150f82d19bbd003
  Author: David Green <david.green at arm.com>
  Date:   2021-02-28 (Sun, 28 Feb 2021)

  Changed paths:
    M llvm/lib/Target/ARM/ARMISelLowering.cpp
    M llvm/test/CodeGen/Thumb2/mve-vmovn.ll

  Log Message:
  -----------
  [ARM] VMOVN undef folding

If we insert undef using a VMOVN, we can just use the original value in
three out of the four possible combinations. Using VMOVT into a undef
vector will still require the lanes to be moved, but otherwise the
non-undef value can be used.