[PATCH] D50840: [InstCombine] Extend collectShuffleElements to support extract/zext/insert patterns

[Renlin Li via Phabricator via llvm-commits]

renlin added a comment.

In https://reviews.llvm.org/D50840#1202564, @joey wrote:

> I haven't worked with the SLPVectorizer before, so would need some guidance in making the change there. Or someone could take over the change, if it's easier.
>
> I found that if I apply the following patch:
>
>   diff --git a/lib/Transforms/Vectorize/SLPVectorizer.cpp b/lib/Transforms/Vectorize/SLPVectorizer.cpp
>   index 32df6d58157..76103732adc 100644
>   --- a/lib/Transforms/Vectorize/SLPVectorizer.cpp
>   +++ b/lib/Transforms/Vectorize/SLPVectorizer.cpp 
>   @@ -2431,8 +2431,10 @@ bool BoUpSLP::isFullyVectorizableTinyTree() {
>        return true;
>   
>      // Gathering cost would be too much for tiny trees.
>   +/*
>      if (VectorizableTree[0].NeedToGather || VectorizableTree[1].NeedToGather)
>        return false;
>   +*/
>


It seems that, the buildvector instructions are not counted in the  VectorizableTree while the cost is properly included as a parameter  to tryToVectorizeList.


Repository:
  rL LLVM

https://reviews.llvm.org/D50840