1 //===- MemRefUtils.cpp - Utilities to support the MemRef dialect ----------===//
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 utilities for the MemRef dialect.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "mlir/Dialect/MemRef/Utils/MemRefUtils.h"
14 #include "mlir/Interfaces/SideEffectInterfaces.h"
15 
16 using namespace mlir;
17 
18 /// Finds a single dealloc operation for the given allocated value.
19 llvm::Optional<Operation *> mlir::findDealloc(Value allocValue) {
20   Operation *dealloc = nullptr;
21   for (Operation *user : allocValue.getUsers()) {
22     auto effectInterface = dyn_cast<MemoryEffectOpInterface>(user);
23     if (!effectInterface)
24       continue;
25     // Try to find a free effect that is applied to one of our values
26     // that will be automatically freed by our pass.
27     SmallVector<MemoryEffects::EffectInstance, 2> effects;
28     effectInterface.getEffectsOnValue(allocValue, effects);
29     const bool isFree =
30         llvm::any_of(effects, [&](MemoryEffects::EffectInstance &it) {
31           return isa<MemoryEffects::Free>(it.getEffect());
32         });
33     if (!isFree)
34       continue;
35     // If we found > 1 dealloc, return None.
36     if (dealloc)
37       return llvm::None;
38     dealloc = user;
39   }
40   return dealloc;
41 }
42