[mlir][vector] Add a custom builder for LowerVectorsOp

[qcolombet]

Summary

The lower_vectors operation of the transform dialect takes a lot of arguments to build.
In order to make C++ code easier to work with when using this instruction, introduce a new structure, named LowerVectorsOptions, that aggregates all the options that are used to build this instruction.

This allows to use patterns like:

LowerVectorsOptions opts;
opts.setOptZ(...)
  .setOptY(...)...;
builder.create<LowerVectorsOp>(target, opts);

Instead of having to pass all N options directly to the builder and set them in the right order.

NFC.

Note: I'm looking whether we can set this structure in a .td file like LoopOptionsAttr but not sure how good/bad this will look.
Note 2: I've derived LowerVectorsOptions from VectorTransformsOptions because LowerVectorsOp needs to cover a couple more options. We could avoid introducing this new structure and stick to VectorTransformsOptions but we would have to pass the missing two booleans, i.e., it felt half way done.

[nicolasvasilache]

Thanks!

[qcolombet]

• Make sure to match the default values of LowerVectorsOp with what is set in the td file (thanks @nicolasvasilache for noticing)

[qcolombet]

Overload the set method for the base options of VectorTransformsOptions to return a LowerVectorsOptions type.

This allows to mix VectorTransformsOptions and LowerVectorsOptions on the same statement. Without this, the base setXXXOpt would return a VectorTransformsOptions and we couldn't chain the newer setYYYOpt.

[qcolombet]

mlir/include/mlir/Dialect/Vector/TransformOps/VectorTransformOps.h

70

That all block may be overkill but is convenient in practice.

mlir/include/mlir/Dialect/Vector/TransformOps/VectorTransformOps.h

 //===- VectorTransformOps.h - Vector transform ops --------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef MLIR_DIALECT_VECTOR_TRANSFORMOPS_VECTORTRANSFORMOPS_H
 #define MLIR_DIALECT_VECTOR_TRANSFORMOPS_VECTORTRANSFORMOPS_H
 
 #include "mlir/Dialect/PDL/IR/PDLTypes.h"
 #include "mlir/Dialect/Transform/IR/TransformInterfaces.h"
+#include "mlir/Dialect/Vector/Transforms/VectorRewritePatterns.h"
 #include "mlir/Dialect/Vector/Transforms/VectorTransforms.h"
 #include "mlir/IR/OpImplementation.h"
 
 namespace mlir {
 namespace vector {
 class VectorOp;
+struct LowerVectorsOptions;
 } // namespace vector
 } // namespace mlir
 
 //===----------------------------------------------------------------------===//
 // Vector Transform Operations
 //===----------------------------------------------------------------------===//
 
 #define GET_OP_CLASSES
 #include "mlir/Dialect/Vector/TransformOps/VectorTransformOps.h.inc"
 
 namespace mlir {
 class DialectRegistry;
 
 namespace vector {
 void registerTransformDialectExtension(DialectRegistry &registry);
+
+/// Helper structure used to hold the different options of LowerVectorsOp.
+struct LowerVectorsOptions : public VectorTransformsOptions {
+  // Have the default values match the LowerVectorsOp values in the td file.
+  LowerVectorsOptions() : VectorTransformsOptions() {
+    setVectorTransformsOptions(VectorContractLowering::OuterProduct);
+    setVectorMultiReductionLowering(
+        VectorMultiReductionLowering::InnerParallel);
+    setVectorTransposeLowering(VectorTransposeLowering::EltWise);
+    setVectorTransferSplit(VectorTransferSplit::LinalgCopy);
+  }
+
+  /// Duplicate the base API of VectorTransformsOptions but return the
+  /// LowerVectorsOptions type. This allows to really set up the different
+  /// options in any order via chained setXXX calls. @{
+  LowerVectorsOptions &setVectorTransformsOptions(VectorContractLowering opt) {
+    VectorTransformsOptions::setVectorTransformsOptions(opt);
+    return *this;
+  }
+
+  LowerVectorsOptions &
+  setVectorMultiReductionLowering(VectorMultiReductionLowering opt) {
+    VectorTransformsOptions::setVectorMultiReductionLowering(opt);
+    return *this;
+  }
+  LowerVectorsOptions &setVectorTransposeLowering(VectorTransposeLowering opt) {
+    VectorTransformsOptions::setVectorTransposeLowering(opt);
+    return *this;
+  }
+  LowerVectorsOptions &setVectorTransferSplit(VectorTransferSplit opt) {
+    VectorTransformsOptions::setVectorTransferSplit(opt);
+    return *this;
+  }
+  /// @}
+
+  bool transposeAVX2Lowering = false;
+  LowerVectorsOptions &setTransposeAVX2Lowering(bool opt) {
+    transposeAVX2Lowering = opt;
+    return *this;
+  }
+
+  bool unrollVectorTransfers = true;
+  LowerVectorsOptions &setUnrollVectorTransfers(bool opt) {
+    unrollVectorTransfers = opt;
+    return *this;
+  }
+};
 } // namespace vector
 } // namespace mlir
 
 #endif // MLIR_DIALECT_VECTOR_TRANSFORMOPS_VECTORTRANSFORMOPS_H

mlir/include/mlir/Dialect/Vector/TransformOps/VectorTransformOps.td

DefaultValuedAttr<VectorTransferSplitAttr,
        "vector::VectorTransferSplit::LinalgCopy">:$split_transfers,
      DefaultValuedAttr<VectorTransposeLoweringAttr,
        "vector::VectorTransposeLowering::EltWise">:$transpose_lowering,
      DefaultValuedAttr<BoolAttr, "false">:$transpose_avx2_lowering,
      DefaultValuedAttr<BoolAttr, "true">:$unroll_vector_transfers
   );
   let results = (outs PDL_Operation:$results);
 
+  let builders = [
+    OpBuilder<(ins "Type":$resultType, "Value":$target,
+      "const vector::LowerVectorsOptions &":$options), [{
+        return build($_builder, $_state, resultType, target,
+          options.vectorContractLowering,
+          options.vectorMultiReductionLowering, options.vectorTransferSplit,
+          options.vectorTransposeLowering, options.transposeAVX2Lowering,
+          options.unrollVectorTransfers);
+      }]
+    >
+  ];
+
   let assemblyFormat = [{
     $target
     oilist (
       `contraction_lowering` `=` $contraction_lowering
       | `multireduction_lowering` `=` $multireduction_lowering
       | `split_transfers` `=` $split_transfers
       | `transpose_lowering` `=` $transpose_lowering
     )
     attr-dict
   }];
 }
 
 #endif // VECTOR_TRANSFORM_OPS