[PATCH] D113774: [SLP]Improve splat detection.

[Alexey Bataev via Phabricator via llvm-commits]

ABataev added inline comments.


================
Comment at: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:2596
     if (isSplat(Entry->Scalars)) {
       OS << "<splat> " << *Entry->Scalars[0];
       return Str;
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anton-afanasyev wrote:
> ABataev wrote:
> > anton-afanasyev wrote:
> > > ABataev wrote:
> > > > anton-afanasyev wrote:
> > > > > Change it or just remove?
> > > > Why?
> > > `Entry->Scalars[0]` can be `undef` with this patch, for this case the output is uninformative.
> > Hard to tell, this is still the very first element of the entry.
> Hmm, but why do we output the very first element specially? If `Scalars = { undef, add .., add .., add .. }`, we label this as `<splat> undef`. I would just remove this block at all, since "splat" now doesn't mean what it meant before.
Better to output all the scalars here, I think


Repository:
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CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D113774/new/

https://reviews.llvm.org/D113774