[PATCH] D125987: [SLP] Account for cost of removing FMA opportunities by horizontal reduction

[Bill Schmidt via Phabricator via llvm-commits]

wjschmidt added inline comments.


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Comment at: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:9668
 
+void SLPVectorizerPass::adjustForFMAs(InstructionCost &Cost,
+                                      ArrayRef<Value *> &VL) {
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RKSimon wrote:
> ABataev wrote:
> > Can this be hidden in the TTI completely anyhow? To avoid the extra calls of the adjustForFMAs completely in SLP.
> +1 - the only problem if that this will probably end up having to be added on a target-by-target basis in getArithmeticInstrCost - hopefully we can provide a helper wrapper so its only a one-liner in each target.
Hi -- sorry, I'll be out of town for the next week, so can't look at this right away.  In the meantime, can you please give me a little bit more idea exactly what you're looking for?  I've expressed my concerns about making direct changes to getArithmeticInstrCost for this in the comments for this revision -- can you please address those?  It's not at all clear to me what you're looking for other than "hide it from SLP somehow."


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  https://reviews.llvm.org/D125987/new/

https://reviews.llvm.org/D125987