[all-commits] [llvm/llvm-project] 9bccf6: [AArch64][LV] Set MaxInterleaving to 4 for Neovers...

[Sjoerd Meijer via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 9bccf61f5fd20a52f997b23a56c13ada72c46eae
      https://github.com/llvm/llvm-project/commit/9bccf61f5fd20a52f997b23a56c13ada72c46eae
  Author: Sjoerd Meijer <smeijer at nvidia.com>
  Date:   2024-11-20 (Wed, 20 Nov 2024)

  Changed paths:
    M llvm/include/llvm/Analysis/TargetTransformInfo.h
    M llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
    M llvm/include/llvm/CodeGen/BasicTTIImpl.h
    M llvm/lib/Analysis/TargetTransformInfo.cpp
    M llvm/lib/Target/AArch64/AArch64Subtarget.cpp
    M llvm/lib/Target/AArch64/AArch64Subtarget.h
    M llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
    M llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h
    M llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
    M llvm/test/Transforms/LoopVectorize/AArch64/interleaving-load-store.ll
    M llvm/test/Transforms/LoopVectorize/AArch64/interleaving-reduction.ll
    A llvm/test/Transforms/LoopVectorize/AArch64/neoverse-epilogue-vect.ll
    M llvm/test/Transforms/LoopVectorize/AArch64/sve-epilog-vect-vscale-tune.ll

  Log Message:
  -----------
  [AArch64][LV] Set MaxInterleaving to 4 for Neoverse V2 and V3 (#100385)

Set the maximum interleaving factor to 4, aligning with the number of available
SIMD pipelines. This increases the number of vector instructions in the vectorised
loop body, enhancing performance during its execution. However, for very low
iteration counts, the vectorised body might not execute at all, leaving only the
epilogue loop to run. This issue affects e.g. cam4_r from SPEC FP, which
experienced a performance regression. To address this, the patch reduces the
minimum epilogue vectorisation factor from 16 to 8, enabling the epilogue to be
vectorised and largely mitigating the regression.



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