llvm/mlir/lib/Dialect/Linalg/Transforms/Hoisting.cpp

//===- Hoisting.cpp - Linalg hoisting transformations ---------------------===//
//
// 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 functions concerned with hoisting invariant operations
// in the context of Linalg transformations.
//
//===----------------------------------------------------------------------===//

#include "mlir/Dialect/Linalg/Transforms/Hoisting.h"
#include "mlir/Analysis/SliceAnalysis.h"
#include "mlir/Dialect/Affine/Analysis/AffineStructures.h"
#include "mlir/Dialect/Affine/IR/AffineOps.h"
#include "mlir/Dialect/Affine/IR/AffineValueMap.h"
#include "mlir/Dialect/Affine/Utils.h"
#include "mlir/Dialect/Arith/IR/Arith.h"
#include "mlir/Dialect/Func/IR/FuncOps.h"
#include "mlir/Dialect/Linalg/IR/Linalg.h"
#include "mlir/Dialect/Linalg/Transforms/Transforms.h"
#include "mlir/Dialect/SCF/IR/SCF.h"
#include "mlir/Dialect/SCF/Utils/Utils.h"
#include "mlir/Dialect/Tensor/IR/Tensor.h"
#include "mlir/Dialect/Vector/IR/VectorOps.h"
#include "mlir/Dialect/Vector/Utils/VectorUtils.h"
#include "mlir/IR/BuiltinOps.h"
#include "mlir/IR/Dominance.h"
#include "mlir/Transforms/GreedyPatternRewriteDriver.h"
#include "mlir/Transforms/LoopInvariantCodeMotionUtils.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/TypeSwitch.h"
#include "llvm/Support/Debug.h"

dbgs;

#define DEBUG_TYPE …

#define DBGS() …

usingnamespacemlir;
usingnamespacemlir::linalg;

/// Replace `loop` with a new loop that has a different init operand at
/// position `index`. The body of this loop is moved over to the new loop.
///
/// `newInitOperands` specifies the replacement "init" operands.
/// `newYieldValue` is the replacement yield value of the loop at position
/// `index`.
static scf::ForOp replaceWithDifferentYield(RewriterBase &rewriter,
                                            scf::ForOp loop,
                                            Value newInitOperand,
                                            unsigned index,
                                            Value newYieldValue) { … }

// Hoist out a pair of corresponding vector.extract+vector.broadcast
// operations. This function transforms a loop like this:
//  %res = scf.for _ = _ to _ step _ iter_args(%iarg = %v) -> (t1) {
//   %e = vector.extract %iarg : t1 to t2
//   %u = "some_use"(%e) : (t2) -> t2
//   %b = vector.broadcast %u : t2 to t1
//   scf.yield %b : t1
//  }
// into the following:
//  %e = vector.extract %v: t1 to t2
//  %res' = scf.for _ = _ to _ step _ iter_args(%iarg = %e) -> (t2) {
//   %u' = "some_use"(%iarg) : (t2) -> t2
//   scf.yield %u' : t2
//  }
//  %res = vector.broadcast %res' : t2 to t1
void mlir::linalg::hoistRedundantVectorBroadcasts(RewriterBase &rewriter,
                                                  Operation *root) { … }

static bool noAliasingUseInLoop(vector::TransferReadOp transferRead,
                                LoopLikeOpInterface loop) { … }

void mlir::linalg::hoistRedundantVectorTransfers(Operation *root) { … }