llvm/mlir/lib/Dialect/Bufferization/Transforms/OptimizeAllocationLiveness.cpp

//===- OptimizeAllocationLiveness.cpp - impl. optimize allocation liveness pass
//-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements a pass for optimizing allocation liveness.
// The pass moves the deallocation operation after the last user of the
// allocated buffer.
//===----------------------------------------------------------------------===//

#include "mlir/Dialect/Bufferization/Transforms/BufferViewFlowAnalysis.h"
#include "mlir/Dialect/Bufferization/Transforms/Passes.h"
#include "mlir/Dialect/Func/IR/FuncOps.h"
#include "mlir/Dialect/MemRef/IR/MemRef.h"
#include "mlir/IR/Operation.h"
#include "llvm/Support/Debug.h"

#define DEBUG_TYPE …
#define DBGS() …
#define LDBG(X) …

namespace mlir {
namespace bufferization {
#define GEN_PASS_DEF_OPTIMIZEALLOCATIONLIVENESS
#include "mlir/Dialect/Bufferization/Transforms/Passes.h.inc"
} // namespace bufferization
} // namespace mlir

usingnamespacemlir;

namespace {

//===----------------------------------------------------------------------===//
// Helper functions
//===----------------------------------------------------------------------===//

/// Return true if `a` happens before `b`, i.e., `a` or one of its ancestors
/// properly dominates `b` and `b` is not inside `a`.
static bool happensBefore(Operation *a, Operation *b) { … }

/// This method searches for a user of value that is a dealloc operation.
/// If multiple users with free effect are found, return nullptr.
Operation *findUserWithFreeSideEffect(Value value) { … }

/// Checks if the given op allocates memory.
static bool hasMemoryAllocEffect(MemoryEffectOpInterface memEffectOp) { … }

struct OptimizeAllocationLiveness
    : public bufferization::impl::OptimizeAllocationLivenessBase<
          OptimizeAllocationLiveness> { … };

} // end anonymous namespace

//===----------------------------------------------------------------------===//
// OptimizeAllocatinliveness construction
//===----------------------------------------------------------------------===//

std::unique_ptr<Pass>
mlir::bufferization::createOptimizeAllocationLivenessPass() { … }