[PATCH] D107541: [AArch64] Cost-model vector concatenation

[Sjoerd Meijer via Phabricator via llvm-commits]

SjoerdMeijer added a comment.

In D107541#2929005 <https://reviews.llvm.org/D107541#2929005>, @dmgreen wrote:

> Can we also add some more tests, for things that are insert_subvector's but not just the simple concat's?

Yeah, I have tried, but unsuccessfully. The shuffle cost for a `SK_InsertSubvector` is guarded by `isInsertSubvectorMask()`:

  if (Shuffle->isInsertSubvectorMask(NumSubElts, SubIndex))
    return TargetTTI->getShuffleCost(
      TTI::SK_InsertSubvector, VecTy, Shuffle->getShuffleMask(),
      SubIndex,
      FixedVectorType::get(VecTy->getScalarType(), NumSubElts));

And this `isInsertSubvectorMask()` seems to only return true for subverter masks that are identity masks, so I haven't been able to trigger this with other masks.


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