[PATCH] D119661: [LV] Support chained phis as incoming values for first-order recurs.

[Florian Hahn via Phabricator via llvm-commits]

fhahn created this revision.
fhahn added reviewers: Ayal, spatel, gilr.
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If the incoming previous value of a first-order recurrence is a phi in
the header, go through incoming values from the latch until we find a
non-phi value. Use this as the new Previous, all uses in the header
will be dominated by the original phi, but need to be moved after
the non-phi previous value.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D119661

Files:
  llvm/lib/Analysis/IVDescriptors.cpp
  llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
  llvm/test/Transforms/LoopVectorize/first-order-recurrence-chains.ll
  llvm/test/Transforms/LoopVectorize/first-order-recurrence.ll

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