[Mlir-commits] [mlir] [mlir][VectorOps] Add vector.interleave operation (1/4) (PR #80965)

[Benjamin Maxwell]

================
@@ -478,6 +478,69 @@ def Vector_ShuffleOp :
   let hasCanonicalizer = 1;
 }
 
+def Vector_InterleaveOp :
+  Vector_Op<"interleave", [Pure,
+    AllTypesMatch<["lhs", "rhs"]>,
+    TypesMatchWith<
+    "type of 'result' is double the width of the inputs",
+    "lhs", "result",
+    [{
+      [&]() -> ::mlir::VectorType {
+        auto vectorType = ::llvm::cast<mlir::VectorType>($_self);
+        ::mlir::VectorType::Builder builder(vectorType);
+        if (vectorType.getRank() == 0) {
+          static constexpr int64_t v2xty_shape[] = { 2 };
+          return builder.setShape(v2xty_shape);
+        }
+        auto lastDim = vectorType.getRank() - 1;
+        return builder.setDim(lastDim, vectorType.getDimSize(lastDim) * 2);
+      }()
+    }]>]> {
+  let summary = "constructs a vector by interleaving two input vectors";
+  let description = [{
+    The interleave operation constructs a new vector by interleaving the
+    elements from the trailing (or final) dimension of two input vectors,
+    returning a new vector where the trailing dimension is twice the size.
+
+    Note that for the n-D case this differs from the interleaving possible with
----------------
MacDue wrote:

In LLVM for scalable vectors shufflevector can only perform a splat, there's no support for any other shuffle masks. An interleave for scalable vectors has to use the special interleave2 intrinsic: https://llvm.org/docs/LangRef.html#llvm-experimental-vector-interleave2-intrinsic.

This is because the fixed-size shuffle mask does not make sense in the context of scalable vectors. The length of the mask may be less than the total number of elements in the two vectors.



https://github.com/llvm/llvm-project/pull/80965