[all-commits] [llvm/llvm-project] 734d11: [ARM] Remove reduce(shuffle) if all the lanes are ...

[David Green via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 734d113a6c88f216b9fe7b8b797006927e3167c6
      https://github.com/llvm/llvm-project/commit/734d113a6c88f216b9fe7b8b797006927e3167c6
  Author: David Green <david.green at arm.com>
  Date:   2023-02-07 (Tue, 07 Feb 2023)

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

  Log Message:
  -----------
  [ARM] Remove reduce(shuffle) if all the lanes are used

This looks for vaddv(shuffle) or vmlav(shuffle, shuffle), with a shuffle where
all the lanes are used once. Due to the reduction being commutative the shuffle
can be removed.

Differential Revision: https://reviews.llvm.org/D143382