[PATCH] D54514: [llvm-exegesis] InstructionBenchmarkClustering::dbScan(): use manual std::deque<size_t> + std::vector<char> instead of SetVector.

[Fangrui Song via Phabricator via llvm-commits]

MaskRay added a comment.

In https://reviews.llvm.org/D54514#1303127, @lebedev.ri wrote:

> In https://reviews.llvm.org/D54514#1303114, @MaskRay wrote:
>
> > Anyway, I think this is superseded by https://reviews.llvm.org/D54442
>
>
> I looked at that, and i think it does at least four things at once:
>
> 1. Exactly what this diff does, `llvm::SetVector<>` -> `std::{CONTAINER}<size_t> Workqueue` + `std::{CONTAINER}<size_t> Set`.
> 2. `std::deque<size_t> Workqueue` -> `std::vector<size_t>` with manual begin/end tracking. FIXME: how does this affect the capacity?
> 3. Not removing from the `Set` after processing.
> 4. `assert` instead of `continue`


The queue does not need to use `std::queue`. It can be pre-allocated and use manual begin/end tracking. This does not affect the capacity (<= N).

  Workqueue.assign(Neighbors.begin(), Neighbors.end()); // only elements that have not been added should be assigned

` if (!ClusterIdForPoint_[Q].isUndef()) {` is unnecessary


Repository:
  rL LLVM

https://reviews.llvm.org/D54514