[PATCH] D146128: [SVE][LoopVectorize] Add option to disable tail-folding for reverse loops

[David Sherwood via Phabricator via llvm-commits]

david-arm created this revision.
david-arm added reviewers: sdesmalen, kmclaughlin, paulwalker-arm, dmgreen, MattDevereau.
Herald added subscribers: shiva0217, ctetreau, psnobl, hiraditya, tschuett.
Herald added a reviewer: efriedma.
Herald added a project: All.
david-arm requested review of this revision.
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If we use tail-folding for reverse loops that contain loads
and stores then we will need to reverse the loop predicate.
This patch adds a new 'reverse' sve-tail-folding option and
ensures they are not considered 'simple'.

Adding this logic required changing the preferPredicateOverEpilogue
TTI interface to pass in a new boolean - NeedsReversePred.
We use a new LoopVectorizationLegality function to determine
whether or not we need a reversed predicate.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D146128

Files:
  llvm/include/llvm/Analysis/TargetTransformInfo.h
  llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
  llvm/include/llvm/CodeGen/BasicTTIImpl.h
  llvm/include/llvm/Transforms/Vectorize/LoopVectorizationLegality.h
  llvm/lib/Analysis/TargetTransformInfo.cpp
  llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
  llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h
  llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp
  llvm/lib/Target/ARM/ARMTargetTransformInfo.h
  llvm/lib/Transforms/Vectorize/LoopVectorizationLegality.cpp
  llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
  llvm/test/Transforms/LoopVectorize/AArch64/sve-tail-folding-option.ll

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