1//===- BufferDeallocationOpInterfaceImpl.cpp ------------------------------===//
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/Arith/Transforms/BufferDeallocationOpInterfaceImpl.h"
10#include "mlir/Dialect/Arith/IR/Arith.h"
11#include "mlir/Dialect/Bufferization/IR/BufferDeallocationOpInterface.h"
12#include "mlir/Dialect/MemRef/IR/MemRef.h"
13#include "mlir/IR/Dialect.h"
14#include "mlir/IR/Operation.h"
15
16using namespace mlir;
17using namespace mlir::bufferization;
18
19namespace {
20/// Provides custom logic to materialize ownership indicator values for the
21/// result value of 'arith.select'. Instead of cloning or runtime alias
22/// checking, this implementation inserts another `arith.select` to choose the
23/// ownership indicator of the operand in the same way the original
24/// `arith.select` chooses the MemRef operand. If at least one of the operand's
25/// ownerships is 'Unknown', fall back to the default implementation.
26///
27/// Example:
28/// ```mlir
29/// // let ownership(%m0) := %o0
30/// // let ownership(%m1) := %o1
31/// %res = arith.select %cond, %m0, %m1
32/// ```
33/// The default implementation would insert a clone and replace all uses of the
34/// result of `arith.select` with that clone:
35/// ```mlir
36/// %res = arith.select %cond, %m0, %m1
37/// %clone = bufferization.clone %res
38/// // let ownership(%res) := 'Unknown'
39/// // let ownership(%clone) := %true
40/// // replace all uses of %res with %clone
41/// ```
42/// This implementation, on the other hand, materializes the following:
43/// ```mlir
44/// %res = arith.select %cond, %m0, %m1
45/// %res_ownership = arith.select %cond, %o0, %o1
46/// // let ownership(%res) := %res_ownership
47/// ```
48struct SelectOpInterface
49 : public BufferDeallocationOpInterface::ExternalModel<SelectOpInterface,
50 arith::SelectOp> {
51 FailureOr<Operation *> process(Operation *op, DeallocationState &state,
52 const DeallocationOptions &options) const {
53 return op; // nothing to do
54 }
55
56 std::pair<Value, Value>
57 materializeUniqueOwnershipForMemref(Operation *op, DeallocationState &state,
58 const DeallocationOptions &options,
59 OpBuilder &builder, Value value) const {
60 auto selectOp = cast<arith::SelectOp>(op);
61 assert(value == selectOp.getResult() &&
62 "Value not defined by this operation");
63
64 Block *block = value.getParentBlock();
65 if (!state.getOwnership(memref: selectOp.getTrueValue(), block).isUnique() ||
66 !state.getOwnership(memref: selectOp.getFalseValue(), block).isUnique())
67 return state.getMemrefWithUniqueOwnership(builder, memref: value,
68 block: value.getParentBlock());
69
70 Value ownership = builder.create<arith::SelectOp>(
71 op->getLoc(), selectOp.getCondition(),
72 state.getOwnership(selectOp.getTrueValue(), block).getIndicator(),
73 state.getOwnership(selectOp.getFalseValue(), block).getIndicator());
74 return {selectOp.getResult(), ownership};
75 }
76};
77
78} // namespace
79
80void mlir::arith::registerBufferDeallocationOpInterfaceExternalModels(
81 DialectRegistry &registry) {
82 registry.addExtension(extensionFn: +[](MLIRContext *ctx, ArithDialect *dialect) {
83 SelectOp::attachInterface<SelectOpInterface>(*ctx);
84 });
85}
86

source code of mlir/lib/Dialect/Arith/Transforms/BufferDeallocationOpInterfaceImpl.cpp