[PATCH] D101076: [SVE][LoopVectorize] Add support for scalable vectorization of first-order recurrences

[Kerry McLaughlin via Phabricator via llvm-commits]

kmclaughlin created this revision.
kmclaughlin added reviewers: sdesmalen, david-arm, c-rhodes, dmgreen, fhahn, DavidTruby.
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kmclaughlin requested review of this revision.
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Adds support for scalable vectorization of loops containing first-order recurrences, e.g:

  for(int i = 0; i < n; i++)
    b[i] =  a[i] + a[i - 1]

This patch changes fixFirstOrderRecurrence for scalable vectors to take vscale into
account when inserting into and extracting from the last lane of a vector.
CreateVectorSplice has been added to construct a vector for the recurrence, which
returns a splice intrinsic for scalable types. For fixed-width the behaviour
remains unchanged as CreateVectorSplice will return a shufflevector instead.

The tests included here are the same as test/Transform/LoopVectorize/first-order-recurrence.ll


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D101076

Files:
  llvm/include/llvm/IR/IRBuilder.h
  llvm/lib/IR/IRBuilder.cpp
  llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
  llvm/test/Transforms/LoopVectorize/AArch64/first-order-recurrence.ll

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