[PATCH] D124769: [SLP] AdjustExtractsCost - remove redundant subvector extraction code

[Alexey Bataev via Phabricator via llvm-commits]

ABataev added a comment.

In D124769#3485656 <https://reviews.llvm.org/D124769#3485656>, @RKSimon wrote:

> OK, redundant probably isn't correct - but we still have the situation that removing this code has no effect on tests any more.
>
> It appears to have been added in D99980 <https://reviews.llvm.org/D99980>.

Its just the tests we have are not affected anymore but some real code is still affected. The test codebase is not full, many cases are missing. Removing this code may cause ineffective vectorization in some corner cases. We need to keep this and fix

  Cost += TTIRef.getShuffleCost(TargetTransformInfo::SK_InsertSubvector,
                                        VecTy, None, 0, EEVTy); <---- 0 is not very correct (too optimistic).

instead.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D124769/new/

https://reviews.llvm.org/D124769