[all-commits] [llvm/llvm-project] 9b9e2d: [Analysis] add optional index parameter to isSplat...

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  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 9b9e2da07dd3b103e5a41a3519d839117d994ffa
      https://github.com/llvm/llvm-project/commit/9b9e2da07dd3b103e5a41a3519d839117d994ffa
  Author: Sanjay Patel <spatel at rotateright.com>
  Date:   2020-02-02 (Sun, 02 Feb 2020)

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

  Log Message:
  -----------
  [Analysis] add optional index parameter to isSplatValue()

We want to allow splat value transforms to improve PR44588 and related bugs:
https://bugs.llvm.org/show_bug.cgi?id=44588
...but to do that, we need to know if values are splatted from the same,
specific index (lane) rather than splatted from an arbitrary index.

We can improve the undef handling with 1-liner follow-ups because the
Constant API optionally allow undefs now.

Differential Revision: https://reviews.llvm.org/D73549