llvm/mlir/lib/Dialect/Tensor/Transforms/EmptyOpPatterns.cpp

//===- EmptyOpPatterns.cpp - Patterns related to tensor.empty folding ----===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
#include "mlir/Dialect/Tensor/IR/Tensor.h"
#include "mlir/Dialect/Tensor/Transforms/Transforms.h"
#include "mlir/IR/PatternMatch.h"
#include "llvm/Support/Debug.h"

usingnamespacemlir;
usingnamespacemlir::tensor;

namespace {

template <typename ReshapeOp>
struct FoldEmptyTensorWithReshapeOp : public OpRewritePattern<ReshapeOp> { … };

/// tensor.empty does not define any tensor contents, so a slice of a
/// tensor.empty can be folded to a smaller tensor.empty.
struct FoldEmptyTensorWithExtractSliceOp
    : public OpRewritePattern<ExtractSliceOp> { … };

/// tensor.empty does not define any tensor contents, so an unpadded pack
/// can be folded away.
struct FoldEmptyTensorWithPackOp : public OpRewritePattern<PackOp> { … };

/// tensor.empty does not define any tensor contents, so an unpack
/// can be folded away.
struct FoldEmptyTensorWithUnPackOp : public OpRewritePattern<UnPackOp> { … };

// Fold concat operation where all the operands are empty.
struct FoldConcatsOfEmpty : public OpRewritePattern<ConcatOp> { … };

} // namespace

void mlir::tensor::populateFoldTensorEmptyPatterns(RewritePatternSet &patterns,
                                                   bool foldSingleUseOnly) { … }