[mlir][Linalg] NFC - Retire dead FusionOnTensors.cpp

2 files changed, 0 insertions, 418 deletions

diff --git a/mlir/lib/Dialect/Linalg/Transforms/CMakeLists.txt b/mlir/lib/Dialect/Linalg/Transforms/CMakeLists.txt
index d3a1a52e7e7a..7877edee6d19 100644
--- a/mlir/lib/Dialect/Linalg/Transforms/CMakeLists.txt
+++ b/mlir/lib/Dialect/Linalg/Transforms/CMakeLists.txt
@@ -14,7 +14,6 @@ add_mlir_dialect_library(MLIRLinalgTransforms
   EraseUnusedOperandsAndResults.cpp
   FusePadOpWithLinalgProducer.cpp
   Fusion.cpp
-  FusionOnTensors.cpp
   Generalization.cpp
   Hoisting.cpp
   HoistPadding.cpp
diff --git a/mlir/lib/Dialect/Linalg/Transforms/FusionOnTensors.cpp b/mlir/lib/Dialect/Linalg/Transforms/FusionOnTensors.cpp
deleted file mode 100644
index 87aade3a3eec..000000000000
--- a/mlir/lib/Dialect/Linalg/Transforms/FusionOnTensors.cpp
+++ /dev/null
@@ -1,417 +0,0 @@
-//===- FusionOnTensors.cpp - Implementation of linalg Fusion --------------===//
-//
-// 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 linalg fusion on tensors
-//
-//===----------------------------------------------------------------------===//
-
-#include "mlir/Analysis/SliceAnalysis.h"
-#include "mlir/Dialect/Affine/IR/AffineOps.h"
-#include "mlir/Dialect/Linalg/IR/Linalg.h"
-#include "mlir/Dialect/Linalg/Passes.h"
-#include "mlir/Dialect/Linalg/Transforms/Transforms.h"
-#include "mlir/Dialect/Linalg/Utils/Utils.h"
-#include "mlir/Dialect/Tensor/IR/Tensor.h"
-#include "mlir/Dialect/Utils/IndexingUtils.h"
-#include "mlir/IR/AffineExpr.h"
-#include "mlir/IR/AffineMap.h"
-#include "mlir/Support/LLVM.h"
-#include <optional>
-
-using namespace mlir;
-using namespace linalg;
-
-//===----------------------------------------------------------------------===//
-// StructuredOp specific helpers.
-//===----------------------------------------------------------------------===//
-
-/// Returns the tiled slice dimensions given the tiled consumer loop dimensions.
-/// The slice defines a hyper rectangular iteration space and fusing the
-/// producer is always possible. However, depending on the consumer indexing
-/// map, not all slice elements may be consumed and the tiles may overlap. In
-/// these cases, fusion introduces redundant computation.
-static SmallVector<int64_t> getTiledSliceDims(OpOperand *consumerOperand,
-                                              ArrayRef<int64_t> tiledLoopDims) {
-  // Get the consumer operand indexing map.
-  auto consumerOp = cast<LinalgOp>(consumerOperand->getOwner());
-  AffineMap indexingMap = consumerOp.getMatchingIndexingMap(consumerOperand);
-
-  // Search the slice dimensions tiled by a tile loop dimension.
-  DenseSet<int64_t> tiledSliceDimIndices;
-  for (const auto &en : enumerate(indexingMap.getResults())) {
-    for (auto tiledLoopDim : tiledLoopDims) {
-      if (en.value().isFunctionOfDim(tiledLoopDim))
-        tiledSliceDimIndices.insert(en.index());
-    }
-  }
-  return {tiledSliceDimIndices.begin(), tiledSliceDimIndices.end()};
-}
-
-/// Given a vector of `tiledSliceDimIndices` that represent the tiled dimensions
-/// of the producer result slice returns the tiled producer loop dimensions.
-/// Example:
-/// ```
-/// %res = linalg.fill(%cst, %input)
-/// scf.for %i
-///   scf.for %j
-///     %slice = tensor.extract_slice %res[%i, %j]
-/// ```
-/// getTiledProducerLoops(%res, [0, 1]) returns the loop indices [0, 1].
-static SmallVector<int64_t>
-getTiledProducerLoops(OpResult producerResult,
-                      ArrayRef<int64_t> tiledSliceDimIndices) {
-  auto producerOp = cast<LinalgOp>(producerResult.getOwner());
-
-  // Get the indexing map of the `producerOp` output operand that matches
-  // ´producerResult´.
-  AffineMap producerIndexingMap = producerOp.getMatchingIndexingMap(
-      producerOp.getDpsInitOperand(producerResult.getResultNumber()));
-
-  // Keep only the tiled result slice dimensions of `producerIndexingMap`.
-  AffineMap tiledProducerIndexingSubMap =
-      producerIndexingMap.getSubMap(SmallVector<unsigned>(
-          tiledSliceDimIndices.begin(), tiledSliceDimIndices.end()));
-
-  // Compute the producer loop indices mapped to the tiled result slice
-  // dimensions. As the output indexing map of structured operations are
-  // projected permutations, `tiledProducerIndexingSubMap` has to be a
-  // projected permutation as well. We can thus obtain the producer loop indices
-  // by getting the positions of the result dimensions.
-  // Example:
-  // (d0, d1, d2) -> (d0, d2) has the result positions [0, 2].
-  assert(tiledProducerIndexingSubMap.isProjectedPermutation() &&
-         "expect slice and producer loop dimensions map one-to-one");
-  SmallVector<int64_t> tiledProducerLoopIndices;
-  llvm::transform(
-      llvm::seq<unsigned>(0, tiledProducerIndexingSubMap.getNumResults()),
-      std::back_inserter(tiledProducerLoopIndices), [&](unsigned idx) {
-        return tiledProducerIndexingSubMap.getDimPosition(idx);
-      });
-
-  return tiledProducerLoopIndices;
-}
-
-/// Returns the producer fused in place of `sliceOp`. Tile the producer operands
-/// along the `tiledSliceDimIndices` and clone the producer. Consider the case
-/// of fusion of an output tensor:
-/// ```
-/// %1 = producer ins(...) outs(%0)
-/// %2 = consumer ins(...) outs(%1)
-/// ```
-/// When consumer is tiled, %1 appears in the loop iter_args:
-/// ```
-/// %1 = producer ins(...) outs(%0)
-/// %2 = scf.for ... iter_args(%1) .. (%bbarg) {
-///   %t1 = tensor.extract_slice %bbarg[..]
-///   %t2 = consumer ins(...) outs(%t1)
-///   %r = tensor.insert_slice %t2, %bbarg[...]
-/// }
-/// ```
-/// Fusing %1 into the loop requires updating iter_args(%1) to iter_args(%0):
-/// ```
-/// %2 = scf.for ... iter_args(%0) .. (%bbarg) {
-///   %t0 = tensor.extract_slice %bbarg[..]
-///   %t1 = producer ins(...) outs(%t0)
-///   %t2 = consumer ins(...) outs(%t1)
-///   %r = tensor.insert_slice %t2, %bbarg[...]
-/// }
-/// ```
-/// This transformation is only valid if %bbarg is exclusively used by the
-/// output ExtractSliceOp / InsertSliceOp pair, which is checked by the
-/// `fuseProducer` method.
-/// TODO: instead of check and failure, insert new iter_args each time a
-/// producer is fused into a consumer and fold away unused iter_args.
-static LinalgOp getTiledProducer(OpBuilder &b, OpResult producerResult,
-                                 tensor::ExtractSliceOp sliceOp,
-                                 ArrayRef<int64_t> tiledSliceDimIndices,
-                                 ArrayRef<int64_t> tiledProducerLoopIndices,
-                                 OpOperand *iterArg) {
-  // Clone the producer after `sliceOp` since the slice may be reused to pass in
-  // the producer result.
-  OpBuilder::InsertionGuard guard(b);
-  b.setInsertionPointAfter(sliceOp);
-
-  // Get the producer.
-  auto producerOp = cast<LinalgOp>(producerResult.getOwner());
-  Location loc = producerOp.getLoc();
-
-  // Obtain the `producerOp` loop bounds and the `sliceOp` ranges.
-  SmallVector<OpFoldResult> producerLoopBounds;
-  llvm::transform(producerOp.createLoopRanges(b, loc),
-                  std::back_inserter(producerLoopBounds),
-                  [&](Range range) { return range.size; });
-  SmallVector<Range> sliceOpRanges = sliceOp.getOrCreateRanges(b, loc);
-
-  // Tile the producer operands given the `sliceOp` ranges. Iterate the
-  // `tiledSliceDimIndices` and store the tile offset and size for the tiled
-  // slice dimension.
-  SmallVector<OpFoldResult> tileIvs(producerOp.getNumLoops(), nullptr);
-  SmallVector<OpFoldResult> tileSizes(producerOp.getNumLoops(),
-                                      b.getIndexAttr(0));
-  SmallVector<OpFoldResult> allIvs(producerOp.getNumLoops(), nullptr);
-  for (auto it : zip(tiledSliceDimIndices, tiledProducerLoopIndices)) {
-    int64_t tiledSliceDim = std::get<0>(it);
-    int64_t tiledProducerLoop = std::get<1>(it);
-    tileIvs[tiledProducerLoop] = sliceOpRanges[tiledSliceDim].offset;
-    tileSizes[tiledProducerLoop] = sliceOpRanges[tiledSliceDim].size;
-    allIvs[tiledProducerLoop] = tileIvs[tiledProducerLoop];
-  }
-  erase_value(tileIvs, OpFoldResult());
-  SmallVector<Value> tiledOperands = producerOp->getOperands();
-  tiledOperands = makeTiledShapes(b, loc, producerOp, tiledOperands, tileIvs,
-                                  tileSizes, producerLoopBounds,
-                                  /**omitPartialTileCheck=*/false);
-
-  // Output fusion has to update the iteration arguments of the tile loop nest.
-  // In particular, the iteration argument of the outermost tile loop needs to
-  // be set to the producer output instead of the producer result and `clonedOp`
-  // shall use the existing `sliceOp` result instead of the tiled producer
-  // output operand.
-  if (iterArg) {
-    OpOperand *outputOperand =
-        producerOp.getDpsInitOperand(producerResult.getResultNumber());
-    iterArg->set(outputOperand->get());
-    tiledOperands[outputOperand->getOperandNumber()] = sliceOp.getResult();
-  }
-
-  // Clone the producer using the tiled producer operands.
-  TypeRange resultTypes = ValueRange(tiledOperands)
-                              .take_back(producerOp.getNumDpsInits())
-                              .getTypes();
-  LinalgOp clonedOp = clone(b, producerOp, resultTypes, tiledOperands);
-
-  // Shift all IndexOp results by the tile offset.
-  offsetIndices(b, clonedOp, allIvs);
-
-  return clonedOp;
-}
-
-//===----------------------------------------------------------------------===//
-// TileLoopNest specific helpers.
-//===----------------------------------------------------------------------===//
-
-bool TileLoopNest::isEmpty() { return tileLoopOps.empty(); }
-
-bool TileLoopNest::isValid() {
-  // Check if `rootOp` has been tiled at least once.
-  if (isEmpty() || tiledRootAndFusedOpsLoops.count(rootOp) == 0)
-    return false;
-
-  // Check if the number of loop operations and dimensions match.
-  if (tileLoopOps.size() != tiledRootAndFusedOpsLoops[rootOp].size())
-    return false;
-
-  // Check if the innermost tile loop is the parent of `tiledOp`.
-  if (rootOp->getParentOp() != tileLoopOps.back())
-    return false;
-
-  // Check if the tile loops are directly nested.
-  return std::adjacent_find(tileLoopOps.begin(), tileLoopOps.end(),
-                            [](Operation *op1, Operation *op2) {
-                              return op1 != op2->getParentOp();
-                            }) == tileLoopOps.end();
-}
-
-SmallVector<BlockArgument> TileLoopNest::getTiedBBArgs(BlockArgument bbArg) {
-  assert(bbArg && "expect the block argument to be non-zero");
-  SmallVector<BlockArgument> bbArgs;
-
-  // Search all tile loop block arguments from inner to outer.
-  for (auto tileLoop : reverse(tileLoopOps)) {
-    if (bbArg.getOwner()->getParentOp() != tileLoop)
-      return {};
-    bbArgs.push_back(bbArg);
-    OpOperand *iterArg = &tileLoop.getOpOperandForRegionIterArg(bbArg);
-    bbArg = dyn_cast<BlockArgument>(iterArg->get());
-  }
-
-  // Reverse the block arguments to order them from outer to inner.
-  return {bbArgs.rbegin(), bbArgs.rend()};
-}
-
-OpOperand *TileLoopNest::getTiedIterArg(BlockArgument bbArg) {
-  // Search all block arguments and return the matching iteration argument.
-  SmallVector<BlockArgument> bbArgs = getTiedBBArgs(bbArg);
-  if (bbArgs.size() != tileLoopOps.size())
-    return nullptr;
-  return &tileLoopOps.front().getOpOperandForRegionIterArg(bbArgs.front());
-}
-
-bool TileLoopNest::hasOtherUses(BlockArgument bbArg,
-                                tensor::ExtractSliceOp sliceOp) {
-  // Check the innermost block argument is either used by the ExtractSliceOp
-  // `sliceOp`, the matching InsertSliceOp, or by a DimOp. Handle other uses
-  // conservatively.
-  for (Operation *op : bbArg.getUsers()) {
-    if (!isa<tensor::DimOp, tensor::InsertSliceOp, tensor::ExtractSliceOp>(op))
-      return false;
-    if (auto extractSliceOp = dyn_cast<tensor::ExtractSliceOp>(op)) {
-      if (extractSliceOp != sliceOp)
-        return false;
-    }
-    if (auto insertSliceOp = dyn_cast<tensor::InsertSliceOp>(op)) {
-      SetVector<Operation *> backwardSlice;
-      getBackwardSlice(insertSliceOp.getSource(), &backwardSlice,
-                       [](Operation *op) {
-                         return isa<LinalgOp, tensor::InsertSliceOp>(op);
-                       });
-      if (backwardSlice.empty() || backwardSlice.front() != sliceOp)
-        return false;
-    }
-  }
-
-  // Check the block arguments, except for the innermost one, have one use.
-  SmallVector<BlockArgument> bbArgs = getTiedBBArgs(bbArg);
-  return !all_of(bbArgs, [&](BlockArgument bbArg) {
-    return bbArg.hasOneUse() || bbArg == bbArgs.back();
-  });
-}
-
-LogicalResult TileLoopNest::tileRootOp(
-    OpBuilder &b, ArrayRef<int64_t> tileSizes,
-    ArrayRef<int64_t> tileInterchange,
-    std::optional<LinalgLoopDistributionOptions> tileDistribution) {
-  // Exit if all tile sizes are zero.
-  if (tileSizes.size() == static_cast<size_t>(count(tileSizes, 0)))
-    return success();
-
-  // Tile the root operation.
-  LinalgTilingOptions tilingOptions;
-  tilingOptions = tilingOptions
-                      .setInterchange(SmallVector<unsigned>(
-                          tileInterchange.begin(), tileInterchange.end()))
-                      .setTileSizes(tileSizes)
-                      .setLoopType(LinalgTilingLoopType::Loops);
-  if (tileDistribution)
-    tilingOptions = tilingOptions.setDistributionOptions(*tileDistribution);
-
-  // TODO: Propagate RewriterBase everywhere.
-  IRRewriter rewriter(b);
-  FailureOr<TiledLinalgOp> tiledRootOp =
-      tileLinalgOp(rewriter, rootOp, tilingOptions);
-
-  // Exit if tiling the root operation fails.
-  if (failed(tiledRootOp))
-    return failure();
-
-  // Replace all uses of the root operation if it has been tiled before. All
-  // uses of the original untiled root operation are updated by the calling pass
-  // or pattern.
-  if (!isEmpty())
-    rootOp->replaceAllUsesWith(tiledRootOp->tensorResults);
-
-  // Transfer the stored `rootOp` loop dimensions if it has been tiled before.
-  if (tiledRootAndFusedOpsLoops.count(rootOp) != 0) {
-    tiledRootAndFusedOpsLoops[tiledRootOp->op] =
-        tiledRootAndFusedOpsLoops[rootOp];
-  }
-
-  // Update the root operation and append the loops and tile loop dimensions.
-  rootOp = tiledRootOp->op;
-  tileLoopOps.append(tiledRootOp->loops.begin(), tiledRootOp->loops.end());
-  for (const auto &en : enumerate(tileSizes)) {
-    // Copy only the tiled loop dimensions with non-zero tile size.
-    if (en.value() == 0)
-      continue;
-    tiledRootAndFusedOpsLoops[rootOp].push_back(tileInterchange[en.index()]);
-  }
-  assert(isValid() && "expect tile loop nest to be valid after tiling");
-  return success();
-}
-
-FailureOr<LinalgOp> TileLoopNest::fuseProducer(OpBuilder &b,
-                                               OpOperand *consumerOpOperand) {
-  // Check if the consumer has been tiled before. For example, it may not have
-  // been tiled if the outermost tile loop is a reduction loop.
-  if (tiledRootAndFusedOpsLoops.count(consumerOpOperand->getOwner()) == 0)
-    return failure();
-
-  assert(this->isValid() &&
-         "expect the tile loop nest to satisfy all invariants");
-
-  // Check the tile loop nest is non-empty.
-  if (isEmpty())
-    return failure();
-
-  // Check `consumerOpOperand` is defined by an ExtractSliceOp.
-  auto sliceOp =
-      consumerOpOperand->get().getDefiningOp<tensor::ExtractSliceOp>();
-  if (!sliceOp)
-    return failure();
-
-  // Check `sliceOp` and `consumerOp` are in the same block.
-  auto consumerOp = cast<LinalgOp>(consumerOpOperand->getOwner());
-  if (sliceOp->getBlock() != rootOp->getBlock() ||
-      consumerOp->getBlock() != rootOp->getBlock())
-    return failure();
-
-  // Check `consumerOpOperand` is not shape-only to avoid fusion if the data is
-  // not used by the `consumerOp` computation.
-  BlockArgument bbArg = consumerOp.getMatchingBlockArgument(consumerOpOperand);
-  if (bbArg.getUses().empty())
-    return failure();
-
-  // Check if the producer is a LinalgOp possibly passed by iteration argument.
-  OpOperand *iterArg = nullptr;
-  auto producerResult = dyn_cast<OpResult>(sliceOp.getSource());
-  if (auto bbArg = dyn_cast<BlockArgument>(sliceOp.getSource())) {
-    iterArg = getTiedIterArg(bbArg);
-    // Check the iteration argument may be used to pass in the producer output.
-    if (!iterArg || hasOtherUses(bbArg, sliceOp))
-      return failure();
-    producerResult = dyn_cast<OpResult>(iterArg->get());
-  }
-  if (!producerResult || !isa<LinalgOp>(producerResult.getOwner()))
-    return failure();
-
-  // Compute the tiled producer slice dimensions given the tiled consumer loops.
-  SmallVector<int64_t> tiledSliceDimIndices = getTiledSliceDims(
-      consumerOpOperand, tiledRootAndFusedOpsLoops[consumerOp]);
-  if (tiledSliceDimIndices.empty())
-    return failure();
-
-  // Compute the tiled producer loop indices.
-  SmallVector<int64_t> tiledProducerLoopIndices =
-      getTiledProducerLoops(producerResult, tiledSliceDimIndices);
-
-  // Tile the producer operands and clone the producer in place of `sliceOp`.
-  LinalgOp clonedOp =
-      getTiledProducer(b, producerResult, sliceOp, tiledSliceDimIndices,
-                       tiledProducerLoopIndices, iterArg);
-  tiledRootAndFusedOpsLoops[clonedOp] = tiledProducerLoopIndices;
-
-  // Cast the `clonedOp` result to gap type mismatches before canonicalization.
-  Type consumerOperandType = consumerOpOperand->get().getType();
-  Value newResult = clonedOp->getResult(producerResult.getResultNumber());
-  if (newResult.getType() != consumerOperandType) {
-    OpBuilder::InsertionGuard guard(b);
-    b.setInsertionPointAfter(clonedOp);
-    newResult = b.create<tensor::CastOp>(producerResult.getLoc(),
-                                         consumerOperandType, newResult);
-  }
-
-  // Replace the `sliceOp` uses except for the `clonedOp` output uses.
-  sliceOp.getResult().replaceAllUsesExcept(newResult, clonedOp);
-  return clonedOp;
-}
-
-ValueRange TileLoopNest::getRootOpReplacementResults() {
-  assert(!isEmpty() && "expect tile loop nest to be non-empty");
-  return tileLoopOps.front()->getOpResults();
-}
-
-SmallVector<LinalgOp> TileLoopNest::getAllTiledAndFusedOps() {
-  SmallVector<LinalgOp> result;
-  for (const auto &kvp : tiledRootAndFusedOpsLoops) {
-    auto linalgOp = dyn_cast<LinalgOp>(kvp.getFirst());
-    assert(linalgOp &&
-           "expect all tiled and fused operations are linalg operations");
-    result.push_back(linalgOp);
-  }
-  return result;
-}