[all-commits] [llvm/llvm-project] 241fe8: [VPlan] Introduce ComputeReductionResult VPInstruc...

[Florian Hahn via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 241fe83704476f81e3438e32b6d988ea123e624d
      https://github.com/llvm/llvm-project/commit/241fe83704476f81e3438e32b6d988ea123e624d
  Author: Florian Hahn <flo at fhahn.com>
  Date:   2024-01-04 (Thu, 04 Jan 2024)

  Changed paths:
    M llvm/lib/Transforms/Vectorize/LoopVectorizationPlanner.h
    M llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
    M llvm/lib/Transforms/Vectorize/VPlan.cpp
    M llvm/lib/Transforms/Vectorize/VPlan.h
    M llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
    M llvm/test/Transforms/LoopVectorize/AArch64/scalable-strict-fadd.ll
    M llvm/test/Transforms/LoopVectorize/AArch64/strict-fadd.ll
    M llvm/test/Transforms/LoopVectorize/AArch64/sve-interleaved-accesses.ll
    M llvm/test/Transforms/LoopVectorize/ARM/tail-fold-multiple-icmps.ll
    M llvm/test/Transforms/LoopVectorize/epilog-vectorization-reductions.ll
    M llvm/test/Transforms/LoopVectorize/first-order-recurrence-sink-replicate-region.ll
    M llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll
    M llvm/test/Transforms/LoopVectorize/reduction-with-invariant-store.ll
    M llvm/test/Transforms/LoopVectorize/vplan-printing.ll

  Log Message:
  -----------
  [VPlan] Introduce ComputeReductionResult VPInstruction opcode. (#70253)

This patch introduces a new ComputeReductionResult opcode to compute the
final reduction result in the middle block. The code from fixReduction
has been moved to ComputeReductionResult, after some earlier cleanup
changes to model parts of fixReduction explicitly elsewhere as needed.

The recipe may be broken down further in the future.

Note that  the phi nodes to merge the reduction result from the trip 
count check and the middle block, to be used as resume value for the
scalar remainder loop are also generated based on 
ComputeReductionResult.

Once we have a VPValue for the reduction result, this can also be
modeled explicitly and moved out of the recipe.