1 //===- BufferizableOpInterfaceImpl.cpp - Impl. of BufferizableOpInterface -===//
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 #include "mlir/Dialect/Arithmetic/Transforms/BufferizableOpInterfaceImpl.h"
10 #include "mlir/Dialect/Arithmetic/IR/Arithmetic.h"
11 #include "mlir/Dialect/Bufferization/IR/BufferizableOpInterface.h"
12 #include "mlir/Dialect/Bufferization/Transforms/BufferUtils.h"
13 #include "mlir/Dialect/MemRef/IR/MemRef.h"
14 #include "mlir/IR/Dialect.h"
15 #include "mlir/IR/Operation.h"
16 
17 using namespace mlir::bufferization;
18 
19 namespace mlir {
20 namespace arith {
21 namespace {
22 
23 /// Bufferization of arith.constant. Replace with memref.get_global.
24 struct ConstantOpInterface
25     : public BufferizableOpInterface::ExternalModel<ConstantOpInterface,
26                                                     arith::ConstantOp> {
27   LogicalResult bufferize(Operation *op, RewriterBase &rewriter,
28                           const BufferizationState &state) const {
29     auto constantOp = cast<arith::ConstantOp>(op);
30 
31     // Only ranked tensors are supported.
32     if (!constantOp.getType().isa<RankedTensorType>())
33       return failure();
34 
35     // Only constants inside a module are supported.
36     auto moduleOp = constantOp->getParentOfType<ModuleOp>();
37     if (!moduleOp)
38       return failure();
39 
40     // Create global memory segment and replace tensor with memref pointing to
41     // that memory segment.
42     GlobalCreator globalCreator(moduleOp);
43     auto globalMemref = globalCreator.getGlobalFor(constantOp);
44     replaceOpWithNewBufferizedOp<memref::GetGlobalOp>(
45         rewriter, op, globalMemref.type(), globalMemref.getName());
46 
47     return success();
48   }
49 
50   bool isWritable(Operation *op, Value value,
51                   const BufferizationState &state) const {
52     // Memory locations returned by memref::GetGlobalOp may not be written to.
53     assert(value.isa<OpResult>());
54     return false;
55   }
56 };
57 
58 struct IndexCastOpInterface
59     : public BufferizableOpInterface::ExternalModel<IndexCastOpInterface,
60                                                     arith::IndexCastOp> {
61   bool bufferizesToMemoryRead(Operation *op, OpOperand &opOperand,
62                               const BufferizationState &state) const {
63     return false;
64   }
65 
66   bool bufferizesToMemoryWrite(Operation *op, OpOperand &opOperand,
67                                const BufferizationState &state) const {
68     return false;
69   }
70 
71   OpResult getAliasingOpResult(Operation *op, OpOperand &opOperand,
72                                const BufferizationState &state) const {
73     return op->getResult(0);
74   }
75 
76   BufferRelation bufferRelation(Operation *op, OpResult opResult,
77                                 const BufferizationState &state) const {
78     return BufferRelation::Equivalent;
79   }
80 
81   LogicalResult bufferize(Operation *op, RewriterBase &rewriter,
82                           const BufferizationState &state) const {
83     auto castOp = cast<arith::IndexCastOp>(op);
84 
85     Value source = *state.getBuffer(rewriter, op->getOpOperand(0) /*in*/);
86     auto sourceType = source.getType().cast<BaseMemRefType>();
87 
88     // Result type should have same layout and address space as the source type.
89     MemRefLayoutAttrInterface layout = {};
90     if (auto rankedMemRefType = sourceType.dyn_cast<MemRefType>())
91       layout = rankedMemRefType.getLayout();
92     Type resultType =
93         getMemRefType(castOp.getType().cast<TensorType>(), state.getOptions(),
94                       layout, sourceType.getMemorySpace());
95 
96     replaceOpWithNewBufferizedOp<arith::IndexCastOp>(rewriter, op, source,
97                                                      resultType);
98     return success();
99   }
100 };
101 
102 } // namespace
103 } // namespace arith
104 } // namespace mlir
105 
106 void mlir::arith::registerBufferizableOpInterfaceExternalModels(
107     DialectRegistry &registry) {
108   registry.addOpInterface<ConstantOp, ConstantOpInterface>();
109   registry.addOpInterface<IndexCastOp, IndexCastOpInterface>();
110 }
111