1//===- RewriteInsertsPass.cpp - MLIR conversion pass ----------------------===//
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 a pass to rewrite sequential chains of
10// `spirv::CompositeInsert` operations into `spirv::CompositeConstruct`
11// operations.
12//
13//===----------------------------------------------------------------------===//
14
15#include "mlir/Dialect/SPIRV/Transforms/Passes.h"
16
17#include "mlir/Dialect/SPIRV/IR/SPIRVOps.h"
18#include "mlir/IR/Builders.h"
19#include "mlir/IR/BuiltinOps.h"
20
21namespace mlir {
22namespace spirv {
23#define GEN_PASS_DEF_SPIRVREWRITEINSERTSPASS
24#include "mlir/Dialect/SPIRV/Transforms/Passes.h.inc"
25} // namespace spirv
26} // namespace mlir
27
28using namespace mlir;
29
30namespace {
31
32/// Replaces sequential chains of `spirv::CompositeInsertOp` operation into
33/// `spirv::CompositeConstructOp` operation if possible.
34class RewriteInsertsPass
35 : public spirv::impl::SPIRVRewriteInsertsPassBase<RewriteInsertsPass> {
36public:
37 void runOnOperation() override;
38
39private:
40 /// Collects a sequential insertion chain by the given
41 /// `spirv::CompositeInsertOp` operation, if the given operation is the last
42 /// in the chain.
43 LogicalResult
44 collectInsertionChain(spirv::CompositeInsertOp op,
45 SmallVectorImpl<spirv::CompositeInsertOp> &insertions);
46};
47
48} // namespace
49
50void RewriteInsertsPass::runOnOperation() {
51 SmallVector<SmallVector<spirv::CompositeInsertOp, 4>, 4> workList;
52 getOperation().walk([this, &workList](spirv::CompositeInsertOp op) {
53 SmallVector<spirv::CompositeInsertOp, 4> insertions;
54 if (succeeded(collectInsertionChain(op, insertions)))
55 workList.push_back(insertions);
56 });
57
58 for (const auto &insertions : workList) {
59 auto lastCompositeInsertOp = insertions.back();
60 auto compositeType = lastCompositeInsertOp.getType();
61 auto location = lastCompositeInsertOp.getLoc();
62
63 SmallVector<Value, 4> operands;
64 // Collect inserted objects.
65 for (auto insertionOp : insertions)
66 operands.push_back(insertionOp.getObject());
67
68 OpBuilder builder(lastCompositeInsertOp);
69 auto compositeConstructOp = builder.create<spirv::CompositeConstructOp>(
70 location, compositeType, operands);
71
72 lastCompositeInsertOp.replaceAllUsesWith(
73 compositeConstructOp->getResult(0));
74
75 // Erase ops.
76 for (auto insertOp : llvm::reverse(insertions)) {
77 auto *op = insertOp.getOperation();
78 if (op->use_empty())
79 insertOp.erase();
80 }
81 }
82}
83
84LogicalResult RewriteInsertsPass::collectInsertionChain(
85 spirv::CompositeInsertOp op,
86 SmallVectorImpl<spirv::CompositeInsertOp> &insertions) {
87 if (isa<spirv::CooperativeMatrixType>(op.getComposite().getType()))
88 return failure();
89
90 auto indicesArrayAttr = cast<ArrayAttr>(op.getIndices());
91 // TODO: handle nested composite object.
92 if (indicesArrayAttr.size() == 1) {
93 auto numElements = cast<spirv::CompositeType>(op.getComposite().getType())
94 .getNumElements();
95
96 auto index = cast<IntegerAttr>(indicesArrayAttr[0]).getInt();
97 // Need a last index to collect a sequential chain.
98 if (index + 1 != numElements)
99 return failure();
100
101 insertions.resize(numElements);
102 while (true) {
103 insertions[index] = op;
104
105 if (index == 0)
106 return success();
107
108 op = op.getComposite().getDefiningOp<spirv::CompositeInsertOp>();
109 if (!op)
110 return failure();
111
112 --index;
113 indicesArrayAttr = cast<ArrayAttr>(op.getIndices());
114 if ((indicesArrayAttr.size() != 1) ||
115 (cast<IntegerAttr>(indicesArrayAttr[0]).getInt() != index))
116 return failure();
117 }
118 }
119 return failure();
120}
121

source code of mlir/lib/Dialect/SPIRV/Transforms/RewriteInsertsPass.cpp