[all-commits] [llvm/llvm-project] 81e9ed: [VectorCombine] forward walk through instructions ...

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  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 81e9ede3a2db32487c15dc20d5d0be6392fb62bc
      https://github.com/llvm/llvm-project/commit/81e9ede3a2db32487c15dc20d5d0be6392fb62bc
  Author: Sanjay Patel <spatel at rotateright.com>
  Date:   2020-05-16 (Sat, 16 May 2020)

  Changed paths:
    M llvm/lib/Transforms/Vectorize/VectorCombine.cpp
    M llvm/test/Transforms/PhaseOrdering/X86/vector-reductions.ll
    M llvm/test/Transforms/VectorCombine/X86/extract-binop.ll
    M llvm/test/Transforms/VectorCombine/X86/insert-binop.ll

  Log Message:
  -----------
  [VectorCombine] forward walk through instructions to improve chaining of transforms

This is split off from D79799 - where I was proposing to fully iterate
over a function until there are no more transforms. I suspect we are
still going to want to do something like that eventually.

But we can achieve the same gains much more efficiently on the current
set of regression tests just by reversing the order that we visit the
instructions.

This may also reduce the motivation for D79078, but we are still not
getting the optimal pattern for a reduction.