[Mlir-commits] [mlir] [mlir][linalg] Implement Conv2D using Winograd Conv2D algorithm (PR #96181)

[Hsiangkai Wang]

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+//===- WinogradConv2D.cpp - Winograd Conv2D implementation ----------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// Implement Winograd Conv2D algorithm. The implementation is based on the
+// paper: Fast Algorithms for Convolutional Neural Networks
+// (https://arxiv.org/abs/1509.09308)
+//
+//===----------------------------------------------------------------------===//
+
+#include "mlir/Dialect/Linalg/IR/Linalg.h"
+#include "mlir/Dialect/Tensor/IR/Tensor.h"
+#include "mlir/Dialect/Tosa/Utils/ConversionUtils.h"
+#include "mlir/Dialect/Utils/StaticValueUtils.h"
+#include "mlir/Transforms/GreedyPatternRewriteDriver.h"
+#include "llvm/Support/MathExtras.h"
+
+namespace mlir {
+namespace linalg {
+
+namespace {
+
+using TransformMapKeyTy = std::pair<int, int>;
+
+/// We use F(m, r) to define the size of minimal filtering algorithms.
+/// m is the output dimension and r is the filter dimension. We can get
+/// the input dimension, alpha, from the formula, alpha = m + r - 1.
+///
+/// For example, when m = 2 and r = 3, we know its input size is 4.
+/// The Conv2D will operate on 4x4 input data with 3x3 filter and get
+/// 2x2 output result.
+constexpr TransformMapKeyTy F_2_3{2, 3};
+constexpr TransformMapKeyTy F_4_3{4, 3};
+constexpr TransformMapKeyTy F_2_5{2, 5};
+
+/// This function generates linalg.batch_matmul to multiply input with filter.
+/// linalg.batch_matmul only supports 3-dimensional inputs. We can treat
+/// tileH x tileW x H x W data as the 1-dimensional data array. That is to
+/// convert [tileH, tileW, H, W, N, C] to [tileH x tileW x H x W, N, C]. In this
+/// way, we can convert 6-dimensional inputs to 3-dimensional representation
+/// that is suitable for linalg.batch_matmul.
+///
+/// Batched matmul will do the matrix multiply with the reduction on channel.
+///
+/// We get
+///
+/// %collapsed_input = tensor.collapse_shape %input
+/// %collapsed_filter = tensor.collapse_shape %filter
+/// %ret = linalg.batch_matmul %collapsed_input, %collapsed_filter
+/// %expanded_ret = tensor.expand_shape %ret
+///
+/// After this function, we get return value with data layout
+/// (tileH, tileW, H, W, N, F).
+static Value matrixMultiply(RewriterBase &rewriter, Location loc,
+                            Value transformedFilter, Value transformedInput,
+                            Type outputElementType) {
+  // Convert (alphaH, alphaW, C, F) to (alphaH x alphaW, C, F) for filter.
+  auto filterType = cast<ShapedType>(transformedFilter.getType());
+  assert(filterType.hasStaticShape() && "only support static shapes.");
+  ArrayRef<int64_t> filterShape = filterType.getShape();
+  Type filterElementType = filterType.getElementType();
+  auto filterReassocType = RankedTensorType::get(
+      {filterShape[0] * filterShape[1], filterShape[2], filterShape[3]},
+      filterElementType);
+  SmallVector<ReassociationIndices> filterReassoc = {{0, 1}, {2}, {3}};
+  Value collapseFilter = rewriter.create<tensor::CollapseShapeOp>(
+      loc, filterReassocType, transformedFilter, filterReassoc);
+
+  // Convert (alphaH, alphaW, tileH, tileW, N, C) to
+  // (alphaH x alphaW, tileH x tileW x N, C) for input.
+  auto inputType = cast<ShapedType>(transformedInput.getType());
+  assert(inputType.hasStaticShape() && "only support static shapes.");
+  ArrayRef<int64_t> inputShape = inputType.getShape();
+  Type inputElementType = inputType.getElementType();
+  auto inputReassocType = RankedTensorType::get(
+      {inputShape[0] * inputShape[1],
+       inputShape[2] * inputShape[3] * inputShape[4], inputShape[5]},
+      inputElementType);
+  SmallVector<ReassociationIndices> inputReassoc = {{0, 1}, {2, 3, 4}, {5}};
+  Value collapseInput = rewriter.create<tensor::CollapseShapeOp>(
+      loc, inputReassocType, transformedInput, inputReassoc);
+
+  // Batched matrix multiply.
+  auto matmulType = RankedTensorType::get(
+      {inputShape[0] * inputShape[1],
+       inputShape[2] * inputShape[3] * inputShape[4], filterShape[3]},
+      outputElementType);
+  Value init = rewriter.create<tensor::EmptyOp>(loc, matmulType.getShape(),
+                                                outputElementType);
+
+  auto matmulOp = rewriter.create<linalg::BatchMatmulOp>(
+      loc, matmulType, ValueRange({collapseInput, collapseFilter}),
+      ValueRange{init});
+
+  // The result shape of batch matmul is (alphaH x alphaW, tileH x tileW x N, F)
+  // Expand matmul result to (alphaH, alphaW, tileH, tileW, N, F).
+  SmallVector<ReassociationIndices> outputReassoc = {{0, 1}, {2, 3, 4}, {5}};
+  auto outputReassocType =
+      RankedTensorType::get({inputShape[0], inputShape[1], inputShape[2],
+                             inputShape[3], inputShape[4], filterShape[3]},
+                            outputElementType);
+  auto expandOutput = rewriter.create<tensor::ExpandShapeOp>(
+      loc, outputReassocType, matmulOp.getResult(0), outputReassoc);
+  return expandOutput;
+}
+
+/// Create an empty tensor with alignedType and insert the value into the
+/// created empty tensor with aligned size.
+static Value insertToAlignedTensor(RewriterBase &rewriter, Location loc,
----------------
Hsiangkai wrote:

Done.

https://github.com/llvm/llvm-project/pull/96181