llvm/mlir/lib/Dialect/MemRef/Transforms/MultiBuffer.cpp

//===----------- MultiBuffering.cpp ---------------------------------------===//
//
// 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 multi buffering transformation.
//
//===----------------------------------------------------------------------===//

#include "mlir/Dialect/Affine/IR/AffineOps.h"
#include "mlir/Dialect/Arith/Utils/Utils.h"
#include "mlir/Dialect/MemRef/IR/MemRef.h"
#include "mlir/Dialect/MemRef/Transforms/Passes.h"
#include "mlir/Dialect/MemRef/Transforms/Transforms.h"
#include "mlir/IR/AffineExpr.h"
#include "mlir/IR/BuiltinAttributes.h"
#include "mlir/IR/Dominance.h"
#include "mlir/IR/PatternMatch.h"
#include "mlir/IR/ValueRange.h"
#include "mlir/Interfaces/LoopLikeInterface.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/Debug.h"

usingnamespacemlir;

#define DEBUG_TYPE …
#define DBGS() …
#define DBGSNL() …

/// Return true if the op fully overwrite the given `buffer` value.
static bool overrideBuffer(Operation *op, Value buffer) { … }

/// Replace the uses of `oldOp` with the given `val` and for subview uses
/// propagate the type change. Changing the memref type may require propagating
/// it through subview ops so we cannot just do a replaceAllUse but need to
/// propagate the type change and erase old subview ops.
static void replaceUsesAndPropagateType(RewriterBase &rewriter,
                                        Operation *oldOp, Value val) { … }

// Transformation to do multi-buffering/array expansion to remove dependencies
// on the temporary allocation between consecutive loop iterations.
// Returns success if the transformation happened and failure otherwise.
// This is not a pattern as it requires propagating the new memref type to its
// uses and requires updating subview ops.
FailureOr<memref::AllocOp>
mlir::memref::multiBuffer(RewriterBase &rewriter, memref::AllocOp allocOp,
                          unsigned multiBufferingFactor,
                          bool skipOverrideAnalysis) { … }

FailureOr<memref::AllocOp>
mlir::memref::multiBuffer(memref::AllocOp allocOp,
                          unsigned multiBufferingFactor,
                          bool skipOverrideAnalysis) { … }