[all-commits] [llvm/llvm-project] 47abbf: [VPlan] Update VPInst::onlyFirstLaneUsed to check ...

[Florian Hahn via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 47abbf4fe956ad1c12832de03c8ae3294eb5cb78
      https://github.com/llvm/llvm-project/commit/47abbf4fe956ad1c12832de03c8ae3294eb5cb78
  Author: Florian Hahn <flo at fhahn.com>
  Date:   2024-02-03 (Sat, 03 Feb 2024)

  Changed paths:
    M llvm/lib/Transforms/Vectorize/VPlan.h
    M llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
    M llvm/test/Transforms/LoopVectorize/pr45679-fold-tail-by-masking.ll
    M llvm/test/Transforms/LoopVectorize/tail-folding-vectorization-factor-1.ll

  Log Message:
  -----------
  [VPlan] Update VPInst::onlyFirstLaneUsed to check users. (#80269)

A VPInstruction only has its first lane used if all users use its first
lane only. Use vputils::onlyFirstLaneUsed to continue checking the
recipe's users to handle more cases.

Besides allowing additional introduction of scalar steps when
interleaving in some cases, this also enables using an Add VPInstruction
to model the increment - as a follow up.