llvm/mlir/lib/Dialect/Linalg/Transforms/ConstantFold.cpp

//===- ConstantFold.cpp - Implementation of constant folding on Linalg ops ===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file implements constant folding on Linalg operations.
//
//===----------------------------------------------------------------------===//

#include "mlir/Dialect/Affine/IR/AffineOps.h"
#include "mlir/Dialect/Linalg/IR/Linalg.h"
#include "mlir/Dialect/Linalg/Transforms/Transforms.h"
#include "mlir/IR/Matchers.h"
#include "mlir/IR/PatternMatch.h"
#include "mlir/Support/LLVM.h"
#include "mlir/Transforms/GreedyPatternRewriteDriver.h"
#include <optional>

usingnamespacemlir;
usingnamespacemlir::linalg;

namespace {
/// Base class for constant folding linalg structured ops with N inputs, 1
/// output, and permutation indexing maps.
///
/// `ConcreteType` should provide methods with signatures
///
/// ```c++
///   bool matchIndexingMaps(LinalgOp linalgOp) const;
///   RegionComputationFn getRegionComputeFn(LinalgOp) const;
/// ```
///
/// The latter inspects the region and returns the computation inside as a
/// functor. The functor will be invoked with constant elements for all inputs
/// and should return the corresponding computed constant element for output.
template <typename ConcreteType>
class FoldConstantBase : public OpInterfaceRewritePattern<LinalgOp> { … };

// Folds linalg.transpose (and linalg.generic ops that are actually transposes)
// on constant values.
struct FoldConstantTranspose : public FoldConstantBase<FoldConstantTranspose> { … };
} // namespace

void mlir::linalg::populateConstantFoldLinalgOperations(
    RewritePatternSet &patterns, const ControlFusionFn &controlFn) { … }