1//===- Interchange.cpp - Linalg interchange transformation ----------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements the linalg interchange transformation.
10//
11//===----------------------------------------------------------------------===//
12
13#include "mlir/Dialect/Affine/IR/AffineOps.h"
14#include "mlir/Dialect/Linalg/IR/Linalg.h"
15#include "mlir/Dialect/Linalg/Transforms/Transforms.h"
16#include "mlir/Dialect/Linalg/Utils/Utils.h"
17#include "mlir/Dialect/Utils/IndexingUtils.h"
18#include "mlir/Dialect/Utils/StructuredOpsUtils.h"
19#include "mlir/Dialect/Vector/IR/VectorOps.h"
20#include "mlir/IR/AffineExpr.h"
21#include "mlir/IR/Matchers.h"
22#include "mlir/IR/PatternMatch.h"
23#include "mlir/Pass/Pass.h"
24#include "mlir/Support/LLVM.h"
25#include "llvm/ADT/ScopeExit.h"
26#include "llvm/Support/Debug.h"
27#include "llvm/Support/raw_ostream.h"
28#include <type_traits>
29
30#define DEBUG_TYPE "linalg-interchange"
31
32using namespace mlir;
33using namespace mlir::linalg;
34
35static LogicalResult
36interchangeGenericOpPrecondition(GenericOp genericOp,
37 ArrayRef<unsigned> interchangeVector) {
38 // Interchange vector must be non-empty and match the number of loops.
39 if (interchangeVector.empty() ||
40 genericOp.getNumLoops() != interchangeVector.size())
41 return failure();
42 // Permutation map must be invertible.
43 if (!inversePermutation(AffineMap::getPermutationMap(interchangeVector,
44 genericOp.getContext())))
45 return failure();
46 return success();
47}
48
49FailureOr<GenericOp>
50mlir::linalg::interchangeGenericOp(RewriterBase &rewriter, GenericOp genericOp,
51 ArrayRef<unsigned> interchangeVector) {
52 if (failed(interchangeGenericOpPrecondition(genericOp, interchangeVector)))
53 return rewriter.notifyMatchFailure(genericOp, "preconditions not met");
54
55 // 1. Compute the inverse permutation map, it must be non-null since the
56 // preconditions are satisfied.
57 MLIRContext *context = genericOp.getContext();
58 AffineMap permutationMap = inversePermutation(
59 map: AffineMap::getPermutationMap(permutation: interchangeVector, context));
60 assert(permutationMap && "unexpected null map");
61
62 // Start a guarded inplace update.
63 rewriter.startOpModification(op: genericOp);
64 auto guard = llvm::make_scope_exit(
65 F: [&]() { rewriter.finalizeOpModification(op: genericOp); });
66
67 // 2. Compute the interchanged indexing maps.
68 SmallVector<AffineMap> newIndexingMaps;
69 for (OpOperand &opOperand : genericOp->getOpOperands()) {
70 AffineMap m = genericOp.getMatchingIndexingMap(&opOperand);
71 if (!permutationMap.isEmpty())
72 m = m.compose(permutationMap);
73 newIndexingMaps.push_back(m);
74 }
75 genericOp.setIndexingMapsAttr(
76 rewriter.getAffineMapArrayAttr(newIndexingMaps));
77
78 // 3. Compute the interchanged iterator types.
79 ArrayRef<Attribute> itTypes = genericOp.getIteratorTypes().getValue();
80 SmallVector<Attribute> itTypesVector;
81 llvm::append_range(C&: itTypesVector, R&: itTypes);
82 SmallVector<int64_t> permutation(interchangeVector);
83 applyPermutationToVector(inVec&: itTypesVector, permutation);
84 genericOp.setIteratorTypesAttr(rewriter.getArrayAttr(itTypesVector));
85
86 // 4. Transform the index operations by applying the permutation map.
87 if (genericOp.hasIndexSemantics()) {
88 OpBuilder::InsertionGuard guard(rewriter);
89 for (IndexOp indexOp :
90 llvm::make_early_inc_range(genericOp.getBody()->getOps<IndexOp>())) {
91 rewriter.setInsertionPoint(indexOp);
92 SmallVector<Value> allIndices;
93 allIndices.reserve(genericOp.getNumLoops());
94 llvm::transform(llvm::seq<uint64_t>(0, genericOp.getNumLoops()),
95 std::back_inserter(allIndices), [&](uint64_t dim) {
96 return rewriter.create<IndexOp>(indexOp->getLoc(), dim);
97 });
98 rewriter.replaceOpWithNewOp<affine::AffineApplyOp>(
99 indexOp, permutationMap.getSubMap(indexOp.getDim()), allIndices);
100 }
101 }
102
103 return genericOp;
104}
105

source code of mlir/lib/Dialect/Linalg/Transforms/Interchange.cpp