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

[Dinar Temirbulatov via Phabricator via llvm-commits]

dtemirbulatov added inline comments.


================
Comment at: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:4290
+  auto Cmp = [](const TreeEntry *LHS, const TreeEntry *RHS) {
+    return LHS->Cost > RHS->Cost;
+  };
----------------
ABataev wrote:
> dtemirbulatov wrote:
> > ABataev wrote:
> > > dtemirbulatov wrote:
> > > > 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.
> > > It may trigger for targets like silvermont or in future for vectorized functions.
> > I measured the BFS approach vs this implementation. And with BFS, it is ~10% less efficient on SPEC2006 INT and ~20% less on compilable SPEC2006 FP. By efficiency, I mean the total number of reduced trees while the whole compilation.
> Could you post it anyway to check if it may be improved?
ok, I might miss something. Thanks.


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

https://reviews.llvm.org/D57779