[all-commits] [llvm/llvm-project] 4ef9cb: [AArch64][LoopVectorize] Disable tail-folding for ...

[david-arm via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 4ef9cb6c170a00a06be39e40a1fad361d244280f
      https://github.com/llvm/llvm-project/commit/4ef9cb6c170a00a06be39e40a1fad361d244280f
  Author: David Sherwood <david.sherwood at arm.com>
  Date:   2022-08-02 (Tue, 02 Aug 2022)

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

  Log Message:
  -----------
  [AArch64][LoopVectorize] Disable tail-folding for SVE when loop has interleaved accesses

If we have interleave groups in the loop we want to vectorise then
we should fall back on normal vectorisation with a scalar epilogue. In
such cases when tail-folding is enabled we'll almost certainly go on to
create vplans with very high costs for all vector VFs and fall back on
VF=1 anyway. This is likely to be worse than if we'd just used an
unpredicated vector loop in the first place.

Once the vectoriser has proper support for analysing all the costs
for each combination of VF and vectorisation style, then we should
be able to remove this.

Added an extra test here:

  Transforms/LoopVectorize/AArch64/sve-tail-folding-option.ll

Differential Revision: https://reviews.llvm.org/D128342