[all-commits] [llvm/llvm-project] b8709a: [LV] Support fixed order recurrences.

[Florian Hahn via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: b8709a9d03f8ba28146f612aa47cc25a44d0723e
      https://github.com/llvm/llvm-project/commit/b8709a9d03f8ba28146f612aa47cc25a44d0723e
  Author: Florian Hahn <flo at fhahn.com>
  Date:   2022-08-18 (Thu, 18 Aug 2022)

  Changed paths:
    M llvm/include/llvm/Analysis/IVDescriptors.h
    M llvm/include/llvm/Transforms/Vectorize/LoopVectorizationLegality.h
    M llvm/lib/Analysis/IVDescriptors.cpp
    M llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
    M llvm/lib/Transforms/Vectorize/LoopVectorizationLegality.cpp
    M llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
    A llvm/test/Transforms/LoopVectorize/first-order-recurrence-chains-vplan.ll
    M llvm/test/Transforms/LoopVectorize/first-order-recurrence-chains.ll
    M llvm/test/Transforms/LoopVectorize/first-order-recurrence.ll

  Log Message:
  -----------
  [LV] Support fixed order recurrences.

If the incoming previous value of a fixed-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.

At the moment, fixed-order recurrences are modeled as a chain of
first-order recurrences.

Reviewed By: Ayal

Differential Revision: https://reviews.llvm.org/D119661