[all-commits] [llvm/llvm-project] ebf83c: [Analysis] simplify code for scaleShuffleMask

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  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: ebf83c36e29ab6f480860de640790795870dcccb
      https://github.com/llvm/llvm-project/commit/ebf83c36e29ab6f480860de640790795870dcccb
  Author: Sanjay Patel <spatel at rotateright.com>
  Date:   2020-03-23 (Mon, 23 Mar 2020)

  Changed paths:
    M llvm/include/llvm/Analysis/VectorUtils.h
    M llvm/unittests/Analysis/VectorUtilsTest.cpp

  Log Message:
  -----------
  [Analysis] simplify code for scaleShuffleMask

This is NFC-ish. The results should be identical, but perf is hopefully
better with the fast-path for no scaling. Added a unit test for that.

The code is adapted from what used to be the DAGCombiner equivalent
function before D76508 (rG0eeee83d7513).