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

[Alexey Bataev via Phabricator via llvm-commits]

ABataev added inline comments.


================
Comment at: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:4670-4671
+        // Create shuffle to resize vector
+        for (unsigned I = 0; I < NumElts; I++)
+          Mask[I] = (I < NumScalars) ? I : UndefMaskElem;
+        V = Builder.CreateShuffleVector(V, UndefValue::get(V->getType()), Mask);
----------------
```
SmallVector<int, 16> Mask(NumElts, UndefMaskElem);
std::iota(Mask.begin(), std::next(Mask.begin(), NumScalars), 0); 
```

Also, I think just `std::iota(Mask.begin(), Mask.end(), 0); ` shall work too


================
Comment at: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:4672-4680
+        V = Builder.CreateShuffleVector(V, UndefValue::get(V->getType()), Mask);
+
+        for (unsigned I = 0; I < NumElts; I++)
+          Mask[I] =
+              (I < MinIndex || I >= MaxIndex) ? I : NumElts - MinIndex + I;
+
+        V = Builder.CreateShuffleVector(
----------------
Can we use `ShuffleBuilder` here?


================
Comment at: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:4672-4680
+        V = Builder.CreateShuffleVector(V, UndefValue::get(V->getType()), Mask);
+
+        for (unsigned I = 0; I < NumElts; I++)
+          Mask[I] =
+              (I < MinIndex || I >= MaxIndex) ? I : NumElts - MinIndex + I;
+
+        V = Builder.CreateShuffleVector(
----------------
ABataev wrote:
> Can we use `ShuffleBuilder` here?
Did you include these costs in the cost model?


================
Comment at: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:5183
+        NumInsertsUsed++;
+      } while (is_contained(Scalars, Insert));
+
----------------
`Scalars.contain(Insert)`


Repository:
  rG LLVM Github Monorepo

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

https://reviews.llvm.org/D98714