[all-commits] [llvm/llvm-project] 95ba55: Reapply "[VPlan] Move predication to VPlanTransfor...

[Florian Hahn via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 95ba5508e5dca4c9a3dd50c80b89e3f56016a4f3
      https://github.com/llvm/llvm-project/commit/95ba5508e5dca4c9a3dd50c80b89e3f56016a4f3
  Author: Florian Hahn <flo at fhahn.com>
  Date:   2025-05-22 (Thu, 22 May 2025)

  Changed paths:
    M llvm/lib/Transforms/Vectorize/CMakeLists.txt
    M llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
    M llvm/lib/Transforms/Vectorize/VPRecipeBuilder.h
    M llvm/lib/Transforms/Vectorize/VPlanConstruction.cpp
    A llvm/lib/Transforms/Vectorize/VPlanPredicator.cpp
    M llvm/lib/Transforms/Vectorize/VPlanTransforms.h
    M llvm/test/Transforms/LoopVectorize/uniform-blend.ll
    M llvm/unittests/Transforms/Vectorize/VPlanTestBase.h

  Log Message:
  -----------
  Reapply "[VPlan] Move predication to VPlanTransform (NFC). (#128420)"

This reverts commit 793bb6b257fa4d9f4af169a4366cab3da01f2e1f.

The recommitted version contains a fix to make sure only the original
phis are processed in convertPhisToBlends nu collecting them in a vector
first. This fixes a crash when no mask is needed, because there is only
a single incoming value.

Original message:
This patch moves the logic to predicate and linearize a VPlan to a
dedicated VPlan transform. It mostly ports the existing logic directly.

There are a number of follow-ups planned in the near future to
further improve on the implementation:
* Edge and block masks are cached in VPPredicator, but the block masks
are still made available to VPRecipeBuilder, so they can be accessed
during recipe construction. As a follow-up, this should be replaced by
adding mask operands to all VPInstructions that need them and use that
during recipe construction.
* The mask caching in a map also means that this map needs updating each
time a new recipe replaces a VPInstruction; this would also be handled
by adding mask operands.

PR: https://github.com/llvm/llvm-project/pull/128420



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