[mlir][vector] Add build method for vector.to_elements

[newling]

The default builder (added in 7aecd7e) requires result types:

build(builder, result, result_types, elements);

but these types are uniquely defined by the input vector elements. This PR adds a builder to do this mechanical type inference.

Testing: not obvious how to unit test this, I can wait until this PR can be stacked with something that can use it, if that's preferred

[llvmbot]

@llvm/pr-subscribers-mlir-vector

@llvm/pr-subscribers-mlir

Author: James Newling (newling)

Changes

The default builder (added in 7aecd7e) requires result types:

build(builder, result, result_types, elements);

but these types are uniquely defined by the input vector elements. This PR adds a builder to do this mechanical type inference.

Testing: not obvious how to unit test this, I can wait until this PR can be stacked with something that can use it, if that's preferred

---

Full diff: https://github.com/llvm/llvm-project/pull/145114.diff

2 Files Affected:

• (modified) mlir/include/mlir/Dialect/Vector/IR/VectorOps.td (+9-2)
• (modified) mlir/lib/Dialect/Vector/IR/VectorOps.cpp (+8)

diff --git a/mlir/include/mlir/Dialect/Vector/IR/VectorOps.td b/mlir/include/mlir/Dialect/Vector/IR/VectorOps.td
index aef156c5f1d05..fc99a8e30ef1f 100644
--- a/mlir/include/mlir/Dialect/Vector/IR/VectorOps.td
+++ b/mlir/include/mlir/Dialect/Vector/IR/VectorOps.td
@@ -798,7 +798,7 @@ def Vector_ToElementsOp : Vector_Op<"to_elements", [
     This operation decomposes all the scalar elements from a vector. The
     decomposed scalar elements are returned in row-major order. The number of
     scalar results must match the number of elements in the input vector type.
-    All the result elements have the same result type, which must match the
+    All the result elements have the same type, which must match the
     element type of the input vector. Scalable vectors are not supported.
 
     Examples:
@@ -813,7 +813,7 @@ def Vector_ToElementsOp : Vector_Op<"to_elements", [
     // %0#0 = %v1[0]
     // %0#1 = %v1[1]
 
-    // Decompose a 2-D.
+    // Decompose a 2-D vector.
     %0:6 = vector.to_elements %v2 : vector<2x3xf32>
     // %0#0 = %v2[0, 0]
     // %0#1 = %v2[0, 1]
@@ -835,6 +835,13 @@ def Vector_ToElementsOp : Vector_Op<"to_elements", [
 
   let arguments = (ins AnyVectorOfAnyRank:$source);
   let results = (outs Variadic<AnyType>:$elements);
+
+
+  let builders = [
+    // Build method that infers the result types from `elements`.
+    OpBuilder<(ins "Value":$elements)>,
+  ];
+
   let assemblyFormat = "$source attr-dict `:` type($source)";
   let hasFolder = 1;
 }
diff --git a/mlir/lib/Dialect/Vector/IR/VectorOps.cpp b/mlir/lib/Dialect/Vector/IR/VectorOps.cpp
index 6f0ac6bb58282..a2921d3c89d14 100644
--- a/mlir/lib/Dialect/Vector/IR/VectorOps.cpp
+++ b/mlir/lib/Dialect/Vector/IR/VectorOps.cpp
@@ -2417,6 +2417,14 @@ LogicalResult ToElementsOp::fold(FoldAdaptor adaptor,
   return foldToElementsFromElements(*this, results);
 }
 
+void vector::ToElementsOp::build(OpBuilder &builder, OperationState &result, Value elements) {
+  auto vectorType = cast<VectorType>(elements.getType());
+  Type elementType = vectorType.getElementType();
+  int64_t nbElements = vectorType.getNumElements();
+  SmallVector<Type> scalarTypes(nbElements, elementType);
+  build(builder, result, scalarTypes, elements);
+}
+
 //===----------------------------------------------------------------------===//
 // FromElementsOp
 //===----------------------------------------------------------------------===//