[PATCH] D98714: [SLP] Add insertelement instructions to vectorizable tree

[Alexey Bataev via Phabricator via llvm-commits]

ABataev added inline comments.


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Comment at: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:2878-2879
+        VL0 = cast<Instruction>(VL[0]);
+        Bundle = BS.tryScheduleBundle(VL, this, S);
+        assert(Bundle && "Bundle isn't scheduled after reordering?");
+      }
----------------
ABataev wrote:
> anton-afanasyev wrote:
> > ABataev wrote:
> > > Why do we need to do this tricky stuff?
> > Why do we need to rearrange `VL`? We make def-use order for this to correctly extract scalars used out-of-tree.
> > 
> > We can get rid of rescheduling here by two ways:
> > 1) Sort `VL` _before_ scheduling, at the beginning of `buildTree_rec()`;
> > 2) Don't sort `VL` at all (use index order made by `findBuildAggregate()` and recover this order every time again when needed.
> > 
> > I'm to try 2) way here.
> Why do you need to reschedule the bundle?
Can you try to sort the VL before calling the buildtree function? To avoid rescheduling?


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  https://reviews.llvm.org/D98714/new/

https://reviews.llvm.org/D98714