[PATCH] D57779: [SLP] Add support for throttling.

[Dinar Temirbulatov via Phabricator via llvm-commits]

dtemirbulatov added inline comments.


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Comment at: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:4290
+  auto Cmp = [](const TreeEntry *LHS, const TreeEntry *RHS) {
+    return LHS->Cost > RHS->Cost;
+  };
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ABataev wrote:
> Not sure that this is the best criterion. I think you also need to include the distance from the head of the tree to the entry, because some big costs can be compensated by the vectorizable nodes in the tree.
> What I would do here is just some kind of level ordering search (BFS) starting from the deepest level.
Hmm, implemented, but I don't see any benefit from that, plus we have to do BFS search. And we are going to throw away any non-vectorizable nodes at 4295.


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Comment at: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:4297
+        Entry->State != TreeEntry::ScatterVectorize) || Entry->Cost <= 0 ||
+        !Entry->Idx)
+      continue;
----------------
ABataev wrote:
> I think you can also exclude entries with the number of operands <= 1.
But why? The only thing that matters here is the cost.


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  https://reviews.llvm.org/D57779/new/

https://reviews.llvm.org/D57779