1 //===- LinalgTransforms.cpp - Linalg transformations as patterns ----------===//
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 logic and helpers to expose Linalg transforms as rewrite
10 // patterns.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "mlir/Dialect/Linalg/Transforms/Transforms.h"
15 #include "mlir/Dialect/Affine/Utils.h"
16 #include "mlir/Dialect/Arithmetic/IR/Arithmetic.h"
17 #include "mlir/Dialect/Linalg/Analysis/DependenceAnalysis.h"
18 #include "mlir/Dialect/Linalg/IR/LinalgOps.h"
19 #include "mlir/Dialect/Linalg/Transforms/HoistPadding.h"
20 #include "mlir/Dialect/Linalg/Utils/Utils.h"
21 #include "mlir/Dialect/SCF/Transforms.h"
22 #include "mlir/Dialect/Tensor/IR/Tensor.h"
23 #include "mlir/Dialect/Utils/StaticValueUtils.h"
24 #include "mlir/Dialect/Utils/StructuredOpsUtils.h"
25 #include "mlir/Dialect/Vector/VectorOps.h"
26 #include "mlir/IR/AffineExpr.h"
27 #include "mlir/IR/Matchers.h"
28 #include "mlir/Pass/Pass.h"
29 #include "mlir/Support/LLVM.h"
30 #include "mlir/Transforms/GreedyPatternRewriteDriver.h"
31 #include "llvm/ADT/ScopeExit.h"
32 #include "llvm/ADT/TypeSwitch.h"
33 #include "llvm/Support/Debug.h"
34 #include "llvm/Support/raw_ostream.h"
35 #include <type_traits>
36 
37 #define DEBUG_TYPE "linalg-transforms"
38 
39 using namespace mlir;
40 using namespace mlir::linalg;
41 
42 #define DBGS() (llvm::dbgs() << "[" DEBUG_TYPE << "]: ")
43 
44 //===----------------------------------------------------------------------===//
45 // Transformations exposed as rewrite patterns.
46 //===----------------------------------------------------------------------===//
47 // Marker used as attribute name in generated Linalg rewriting transformations.
48 const StringLiteral mlir::linalg::LinalgTransforms::kLinalgTransformMarker =
49     "__internal_linalg_transform__";
50 
51 mlir::linalg::LinalgTransformationFilter::LinalgTransformationFilter(
52     ArrayRef<StringAttr> matchDisjunction, Optional<StringAttr> replacement)
53     : matchDisjunction(matchDisjunction.begin(), matchDisjunction.end()),
54       replacement(replacement), matchByDefault(false) {}
55 
56 mlir::linalg::LinalgTransformationFilter::LinalgTransformationFilter(
57     FilterFunction f, ArrayRef<StringAttr> matchDisjunction,
58     Optional<StringAttr> replacement)
59     : filters(),
60       matchDisjunction(matchDisjunction.begin(), matchDisjunction.end()),
61       replacement(replacement), matchByDefault(false) {
62   if (f)
63     filters.push_back(f);
64 }
65 
66 LogicalResult mlir::linalg::LinalgTransformationFilter::checkAndNotify(
67     PatternRewriter &rewriter, Operation *op) const {
68   if (llvm::any_of(filters,
69                    [&](const FilterFunction &f) { return failed(f(op)); }))
70     return failure();
71 
72   auto attr = op->template getAttrOfType<StringAttr>(
73       LinalgTransforms::kLinalgTransformMarker);
74 
75   if (!attr) {
76     // 1. Has no filter case and matchDisjunction is empty.
77     if (matchDisjunction.empty() || matchByDefault)
78       return success();
79 
80     // 2. Has no filter but was expecting a filter.
81     return rewriter.notifyMatchFailure(op, [&](Diagnostic &diag) {
82       diag << " does not have any filter from list: ";
83       interleaveComma(matchDisjunction, diag);
84     });
85   }
86 
87   // 4. Match explicit filter.
88   for (auto filter : matchDisjunction)
89     if (attr.getValue() == filter)
90       return success();
91 
92   // 5. Fail to match.
93   return rewriter.notifyMatchFailure(op, [&](Diagnostic &diag) {
94     diag << " does not have any filter from list: ";
95     interleaveComma(matchDisjunction, diag);
96   });
97 }
98 
99 void mlir::linalg::LinalgTransformationFilter::
100     replaceLinalgTransformationFilter(PatternRewriter &rewriter,
101                                       Operation *op) const {
102   if (replacement.hasValue())
103     op->setAttr(LinalgTransforms::kLinalgTransformMarker,
104                 replacement.getValue());
105   else
106     op->removeAttr(
107         rewriter.getStringAttr(LinalgTransforms::kLinalgTransformMarker));
108 }
109 
110 bool mlir::linalg::LinalgTransformationFilter::hasReplacementFilter(
111     Operation *op) const {
112   if (!replacement)
113     return false;
114   auto attr = op->getAttr(LinalgTransforms::kLinalgTransformMarker)
115                   .dyn_cast<StringAttr>();
116   return attr && attr == replacement.getValue();
117 }
118 
119 LinalgTilingOptions &
120 mlir::linalg::LinalgTilingOptions::setTileSizes(ArrayRef<int64_t> ts) {
121   assert(!tileSizeComputationFunction && "tile sizes already set");
122   SmallVector<int64_t, 4> tileSizes(ts.begin(), ts.end());
123   tileSizeComputationFunction = [tileSizes](OpBuilder &b, Operation *op) {
124     OpBuilder::InsertionGuard guard(b);
125     b.setInsertionPointToStart(
126         &op->getParentOfType<FuncOp>().getBody().front());
127     return llvm::to_vector<4>(map_range(tileSizes, [&](int64_t s) {
128       Value v = b.create<arith::ConstantIndexOp>(op->getLoc(), s);
129       return v;
130     }));
131   };
132   return *this;
133 }
134 
135 LinalgTilingOptions &mlir::linalg::LinalgTilingOptions::scalarizeDynamicDims() {
136   assert(!tileSizeComputationFunction && "tile sizes already set");
137   tileSizeComputationFunction = [](OpBuilder &b, Operation *op) {
138     SmallVector<Value, 4> tileSizes;
139     auto linalgOp = dyn_cast<LinalgOp>(op);
140     if (!linalgOp)
141       return tileSizes;
142     Location loc = linalgOp.getLoc();
143     auto allShapeSizes = linalgOp.createFlatListOfOperandDims(b, loc);
144     AffineMap map = linalgOp.getShapesToLoopsMap();
145     if (!map)
146       return tileSizes;
147     auto shapeSizes = applyMapToValues(b, loc, map, allShapeSizes);
148     // If the shape size is dynamic, tile by 1. Otherwise, do not tile (tile
149     // size 0).
150     for (Value shapeSize : shapeSizes)
151       tileSizes.push_back(getConstantIntValue(shapeSize).hasValue()
152                               ? b.create<arith::ConstantIndexOp>(loc, 0)
153                               : b.create<arith::ConstantIndexOp>(loc, 1));
154     return tileSizes;
155   };
156   return *this;
157 }
158 
159 /// Helper function that tries to pad `opOperand`. Exit early for scalar
160 /// operands, if `paddingFunc` returns failure, or if `opOperand` is not defined
161 /// by an ExtractSliceOp. Otherwise, try to pad the operand even if it already
162 /// has a static shape. Set `result` to the result of the created PadTensorOp or
163 /// and return success if the operand either has been padded to a static shape
164 /// or already had a static shape and failure otherwise.
165 static LogicalResult padOperandToSmallestStaticBoundingBox(
166     OpBuilder &b, linalg::LinalgOp opToPad, OpOperand *opOperand,
167     const PaddingValueComputationFunction &paddingFunc,
168     const PaddingNoFoldComputationFunction &nofoldFunc, Value &result) {
169   // Get the shape of the operand and check if it has a dynamic shape. Only
170   // return failure if the operand is not a scalar and has a dynamic shape.
171   ArrayRef<int64_t> shape = opToPad.getShape(opOperand);
172   bool hasDynamicShape = llvm::is_contained(shape, ShapedType::kDynamicSize);
173 
174   // Cannot pad scalar operands.
175   if (shape.empty())
176     return success();
177 
178   // Cannot pad if the padding value is unknown.
179   FailureOr<Value> paddingValue = paddingFunc(b, *opOperand);
180   if (failed(paddingValue))
181     return failure(hasDynamicShape);
182 
183   // Cannot construct a static bounding box if the operand is not defined by an
184   // ExtractSliceOp.
185   auto sliceOp = opOperand->get().getDefiningOp<tensor::ExtractSliceOp>();
186   if (!sliceOp)
187     return failure(hasDynamicShape);
188 
189   // Upper bound the `sliceOp` sizes to obtain a static bounding box.
190   SmallVector<int64_t> staticSizes;
191   staticSizes.reserve(opToPad.getRank(opOperand));
192   auto shapedOp = cast<OffsetSizeAndStrideOpInterface>(sliceOp.getOperation());
193   for (auto size : shapedOp.getMixedSizes()) {
194     // If the size is an attribute add it directly to `staticSizes`.
195     if (size.is<Attribute>()) {
196       staticSizes.push_back(
197           size.get<Attribute>().dyn_cast<IntegerAttr>().getInt());
198       continue;
199     }
200     // Otherwise, try to compute a constant upper bound for the size value.
201     FailureOr<int64_t> upperBound =
202         getConstantUpperBoundForIndex(size.get<Value>());
203     if (failed(upperBound)) {
204       LLVM_DEBUG(DBGS() << "No constant bounding box can be found for padding");
205       return failure();
206     }
207     staticSizes.push_back(upperBound.getValue());
208   }
209 
210   // Pad the operand to the bounding box defined by `staticSizes`.
211   auto staticTensorType = RankedTensorType::get(
212       staticSizes, getElementTypeOrSelf(opOperand->get()));
213   bool nofold = nofoldFunc ? nofoldFunc(*opOperand) : false;
214   result =
215       makeComposedPadHighOp(b, opToPad->getLoc(), staticTensorType,
216                             opOperand->get(), paddingValue.getValue(), nofold);
217   return success();
218 }
219 
220 FailureOr<SmallVector<Value>>
221 linalg::rewriteAsPaddedOp(OpBuilder &b, LinalgOp opToPad,
222                           const PaddingValueComputationFunction &paddingFunc,
223                           const PaddingNoFoldComputationFunction &nofoldFunc,
224                           LinalgOp &paddedOp) {
225   Location loc = opToPad->getLoc();
226 
227   // TODO: there are cases where we may still want to pad to larger sizes.
228   assert(opToPad.hasTensorSemantics() &&
229          "expected operation to have tensor semantics");
230 
231   OpBuilder::InsertionGuard g(b);
232   // Set IP after op because we also take the dims of the original output.
233   b.setInsertionPointAfter(opToPad);
234   // Make a copy of the shaped operands and update it.
235   SmallVector<Value> newOperands;
236   newOperands.reserve(opToPad.getNumInputsAndOutputs());
237   for (OpOperand *opOperand : opToPad.getInputAndOutputOperands()) {
238     Value paddedOperand;
239     // If padding was requested but the shape cannot be bounded statically then
240     // the pattern fails to apply.
241     if (failed(padOperandToSmallestStaticBoundingBox(
242             b, opToPad, opOperand, paddingFunc, nofoldFunc, paddedOperand)))
243       return failure();
244     newOperands.push_back(paddedOperand ? paddedOperand : opOperand->get());
245   }
246 
247   SmallVector<SmallVector<Value>> reifiedResultShapes;
248   if (failed(cast<ReifyRankedShapedTypeOpInterface>(opToPad.getOperation())
249                  .reifyResultShapes(b, reifiedResultShapes)))
250     return failure();
251   assert(reifiedResultShapes.size() == opToPad->getNumResults() &&
252          "expected same number of results");
253 
254   // Clone `opToPad` to operate on the statically padded shapes.
255   auto resultTensorTypes =
256       ValueRange(newOperands).take_back(opToPad.getNumOutputs()).getTypes();
257   paddedOp = opToPad.clone(b, loc, resultTensorTypes, newOperands);
258 
259   // Recover the slice out of the new static results. This keeps the original
260   // linalg op around because it uses the dims of the original results.
261   SmallVector<Value> paddedSubviewResults;
262   paddedSubviewResults.reserve(opToPad->getNumResults());
263   for (auto en : llvm::enumerate(paddedOp->getResults())) {
264     Value paddedResult = en.value();
265     int64_t resultNumber = en.index();
266     int64_t rank = paddedResult.getType().cast<RankedTensorType>().getRank();
267     SmallVector<OpFoldResult> offsets(rank, b.getIndexAttr(0));
268     SmallVector<OpFoldResult> sizes;
269     for (Value v : reifiedResultShapes[resultNumber])
270       sizes.push_back(getAsOpFoldResult(v));
271     SmallVector<OpFoldResult> strides(rank, b.getIndexAttr(1));
272     paddedSubviewResults.push_back(b.create<tensor::ExtractSliceOp>(
273         loc, paddedResult, offsets, sizes, strides));
274   }
275   return paddedSubviewResults;
276 }
277 
278 /// Linalg base tiling pattern.
279 mlir::linalg::LinalgBaseTilingPattern::LinalgBaseTilingPattern(
280     StringRef opName, MLIRContext *context, LinalgTilingOptions options,
281     LinalgTransformationFilter filter, PatternBenefit benefit)
282     : RewritePattern(opName, benefit, context), filter(filter),
283       options(options) {}
284 
285 mlir::linalg::LinalgBaseTilingPattern::LinalgBaseTilingPattern(
286     MLIRContext *context, LinalgTilingOptions options,
287     LinalgTransformationFilter filter, PatternBenefit benefit)
288     : RewritePattern(MatchAnyOpTypeTag(), benefit, context), filter(filter),
289       options(options) {}
290 
291 /// Try to peel a loop `op` and return the new result.
292 // TODO: Add support for scf.parallel and affine.for loops.
293 static SmallVector<Value, 4> peelLoop(RewriterBase &rewriter, Operation *op) {
294   return llvm::TypeSwitch<Operation *, SmallVector<Value, 4>>(op)
295       .Case<scf::ForOp>([&](scf::ForOp forOp) {
296         scf::ForOp partialIteration;
297         if (succeeded(scf::peelAndCanonicalizeForLoop(rewriter, forOp,
298                                                       partialIteration)))
299           return partialIteration->getResults();
300         assert(!partialIteration && "expected that loop was not peeled");
301         return forOp->getResults();
302       })
303       .Default([&](Operation *op) { return op->getResults(); });
304 }
305 
306 /// Try to peel a TiledLoopOp and return the new result.
307 static SmallVector<Value, 4> peelLoop(RewriterBase &rewriter,
308                                       TiledLoopOp tiledLoop, int64_t idx) {
309   assert(idx < static_cast<int64_t>(tiledLoop.iterator_types().size()) &&
310          "requested peeling of non-existing loop");
311   TiledLoopOp result;
312   if (succeeded(peelAndCanonicalizeTiledLoop(rewriter, tiledLoop, idx, result)))
313     return result->getResults();
314   assert(!result && "expected that loop was not peeled");
315   return tiledLoop->getResults();
316 }
317 
318 /// Peel loops after tiling.
319 static void peelLoops(RewriterBase &rewriter, TiledLinalgOp &res,
320                       const LinalgTilingOptions &options) {
321   for (int64_t loop : options.peeledLoops) {
322     assert(loop < static_cast<int64_t>(res.loops.size()) &&
323            "requested peeling of non-existing loop");
324     SmallVector<Value, 4> loopResults;
325     Operation *loopOp = res.loops[loop];
326     if (options.loopType == LinalgTilingLoopType::TiledLoops) {
327       assert(llvm::all_of(
328                  res.loops,
329                  [&](Operation *op) { return op == res.loops.front(); }) &&
330              "expected that all loop ops are the same TiledLoopOp");
331       auto tiledLoopOp = dyn_cast<TiledLoopOp>(loopOp);
332       assert(tiledLoopOp && "expected TiledLoopOp");
333       loopResults = peelLoop(rewriter, tiledLoopOp, loop);
334     } else {
335       loopResults = peelLoop(rewriter, loopOp);
336     }
337 
338     // The result of the loop nest may change with peeling.
339     if (res.tensorResults.size() == loopOp->getNumResults() &&
340         std::equal(res.tensorResults.begin(), res.tensorResults.end(),
341                    loopOp->getResults().begin()))
342       res.tensorResults = loopResults;
343   }
344 }
345 
346 LogicalResult mlir::linalg::LinalgBaseTilingPattern::matchAndRewriteBase(
347     Operation *op, PatternRewriter &rewriter, TiledLinalgOp &result) const {
348   LinalgOp linalgOp = dyn_cast<LinalgOp>(op);
349   if (!linalgOp)
350     return failure();
351   if (failed(filter.checkAndNotify(rewriter, linalgOp)))
352     return failure();
353 
354   Optional<TiledLinalgOp> res = tileLinalgOp(rewriter, linalgOp, options);
355 
356   if (!res)
357     return failure();
358   // Clear filter to stop recursive pattern application.
359   filter.replaceLinalgTransformationFilter(rewriter, res->op);
360 
361   // Peel loops.
362   peelLoops(rewriter, *res, options);
363 
364   result = *res;
365   return success();
366 }
367 
368 static ValueRange getTiledOpResult(TiledLinalgOp tiledOp) {
369   if (tiledOp.loops.empty())
370     return tiledOp.op.getOperation()->getResults();
371   return tiledOp.loops.front()->getResults();
372 }
373 
374 static ValueRange
375 getTiledAndFusedOpResult(TiledAndFusedLinalgOps tiledAndFusedOp) {
376   if (tiledAndFusedOp.fusedLoops.empty())
377     return tiledAndFusedOp.op.getOperation()->getResults();
378   return tiledAndFusedOp.fusedLoops.front()->getResults();
379 }
380 
381 mlir::linalg::LinalgBaseTileAndFusePattern::LinalgBaseTileAndFusePattern(
382     StringRef opName, MLIRContext *context,
383     const LinalgDependenceGraph &dependenceGraph,
384     LinalgTilingOptions tilingOptions, LinalgFusionOptions fusionOptions,
385     LinalgTransformationFilter filter, LinalgTransformationFilter fusedOpMarker,
386     LinalgTransformationFilter originalOpMarker, PatternBenefit benefit)
387     : RewritePattern(opName, benefit, context, {}),
388       dependenceGraph(dependenceGraph), tilingOptions(tilingOptions),
389       fusionOptions(fusionOptions), filter(filter),
390       fusedOpMarker(fusedOpMarker), originalOpMarker(originalOpMarker) {}
391 
392 LogicalResult mlir::linalg::LinalgBaseTileAndFusePattern::matchAndRewrite(
393     Operation *op, PatternRewriter &rewriter) const {
394   LinalgOp linalgOp = dyn_cast<LinalgOp>(op);
395   // TODO: remove hasIndexSemantics check once index ops are supported.
396   if (!linalgOp || linalgOp.hasIndexSemantics())
397     return failure();
398   if (failed(filter.checkAndNotify(rewriter, linalgOp)))
399     return failure();
400 
401   DenseSet<Operation *> producers;
402   producers.insert(linalgOp);
403   for (auto dependence : dependenceGraph.getDependentOperationsInto(linalgOp)) {
404     Optional<unsigned> operandNumber = dependence.getIndexingOpViewOperandNum();
405     // When looking at dependences into, indexingOp is always OpOperand. We
406     // could assert, but continue if this is not the case.
407     if (!operandNumber)
408       continue;
409     if (!fusionOptions.indicesToFuse.count(operandNumber.getValue()))
410       continue;
411     if (isa<LinalgOp>(dependence.getDependentOp()))
412       producers.insert(dependence.getDependentOp());
413   }
414 
415   SmallVector<LinalgOp, 1> fusionOps;
416   for (auto it = op->getBlock()->begin(), ie = Block::iterator(op); it != ie;
417        ++it) {
418     auto producerLinalgOp = dyn_cast<LinalgOp>(&(*it));
419     if (producerLinalgOp && producers.count(producerLinalgOp))
420       fusionOps.push_back(producerLinalgOp);
421   }
422   fusionOps.push_back(linalgOp);
423 
424   SmallVector<Value, 4> tileSizes =
425       tilingOptions.tileSizeComputationFunction(rewriter, op);
426   LinalgTilingOptions instanceTilingOptions = tilingOptions;
427   instanceTilingOptions.setTileSizes(tileSizes);
428   Optional<TiledAndFusedLinalgOps> tiledAndFusedOps = tileAndFuseLinalgOps(
429       rewriter, fusionOps, dependenceGraph, instanceTilingOptions);
430   if (!tiledAndFusedOps)
431     return failure();
432 
433   // Tile the unfused loops;
434   SmallVector<Value, 4> unfusedLoopTileSizes;
435   Value zero = rewriter.create<arith::ConstantIndexOp>(op->getLoc(), 0);
436   for (auto tileSize : enumerate(tileSizes)) {
437     if (tiledAndFusedOps->fusedLoopDims.count(tileSize.index()))
438       unfusedLoopTileSizes.push_back(zero);
439     else
440       unfusedLoopTileSizes.push_back(tileSize.value());
441   }
442   // Tile the loop only if there is a non-zero tile size.
443   if (unfusedLoopTileSizes.size() > linalgOp.getNumLoops())
444     unfusedLoopTileSizes.resize(linalgOp.getNumLoops());
445   if (llvm::any_of(unfusedLoopTileSizes, [](Value val) {
446         if (auto cst = val.getDefiningOp<arith::ConstantIndexOp>())
447           return cst.value() != 0;
448         return true;
449       })) {
450     LinalgTilingOptions unfusedTilingOptions = tilingOptions;
451     unfusedTilingOptions.setTileSizes(unfusedLoopTileSizes);
452     Optional<TiledLinalgOp> unfusedTiledOp =
453         tileLinalgOp(rewriter, tiledAndFusedOps->op, unfusedTilingOptions);
454     if (!unfusedTiledOp)
455       return failure();
456     rewriter.replaceOp(tiledAndFusedOps->op,
457                        getTiledOpResult(unfusedTiledOp.getValue()));
458     tiledAndFusedOps->op = unfusedTiledOp->op;
459   }
460   op->replaceAllUsesWith(getTiledAndFusedOpResult(tiledAndFusedOps.getValue()));
461 
462   filter.replaceLinalgTransformationFilter(rewriter,
463                                            tiledAndFusedOps->op.getOperation());
464   for (auto fusedOp : tiledAndFusedOps->fusedProducers) {
465     fusedOpMarker.replaceLinalgTransformationFilter(rewriter,
466                                                     fusedOp.getOperation());
467   }
468   for (auto origProducerOp : ArrayRef<LinalgOp>(fusionOps).drop_back()) {
469     originalOpMarker.replaceLinalgTransformationFilter(
470         rewriter, origProducerOp.getOperation());
471   }
472   rewriter.updateRootInPlace(op, [&]() {
473     originalOpMarker.replaceLinalgTransformationFilter(rewriter, op);
474   });
475   return success();
476 }
477 
478 /// Linalg padding pattern.
479 mlir::linalg::LinalgPaddingPattern::LinalgPaddingPattern(
480     MLIRContext *context, LinalgPaddingOptions options,
481     LinalgTransformationFilter filter, PatternBenefit benefit)
482     : RewritePattern(MatchAnyOpTypeTag(), benefit, context), filter(filter),
483       options(options) {}
484 
485 mlir::linalg::LinalgPaddingPattern::LinalgPaddingPattern(
486     StringRef opName, MLIRContext *context, LinalgPaddingOptions options,
487     LinalgTransformationFilter filter, PatternBenefit benefit)
488     : RewritePattern(opName, benefit, context, {}), filter(filter),
489       options(options) {}
490 
491 LogicalResult mlir::linalg::LinalgPaddingPattern::matchAndRewrite(
492     Operation *op, PatternRewriter &rewriter) const {
493   LinalgOp linalgOp = dyn_cast<LinalgOp>(op);
494   if (!linalgOp)
495     return failure();
496   if (!linalgOp.hasTensorSemantics())
497     return failure();
498   if (failed(filter.checkAndNotify(rewriter, op)))
499     return failure();
500 
501   // Pad the operation.
502   LinalgOp paddedOp;
503   FailureOr<SmallVector<Value>> newResults = rewriteAsPaddedOp(
504       rewriter, linalgOp, options.paddingValueComputationFunction,
505       options.paddingNoFoldComputationFunction, paddedOp);
506   if (failed(newResults))
507     return failure();
508 
509   // Compute the desired hoisting depths.
510   SmallVector<int64_t> depths;
511   if (options.paddingHoistComputationFunction) {
512     for (OpOperand *opOperand : linalgOp.getInputAndOutputOperands())
513       depths.push_back(options.paddingHoistComputationFunction(*opOperand));
514   }
515 
516   // Hoist the padding.
517   for (auto en : enumerate(depths)) {
518     OpOperand &opOperand = paddedOp->getOpOperand(en.index());
519     auto padTensorOp = opOperand.get().getDefiningOp<PadTensorOp>();
520     if (!padTensorOp || en.value() == 0)
521       continue;
522     PadTensorOp hoistedOp;
523     FailureOr<Value> newResult =
524         hoistPaddingOnTensors(padTensorOp, en.value(), hoistedOp);
525     if (failed(newResult))
526       continue;
527     rewriter.replaceOp(padTensorOp, newResult.getValue());
528   }
529 
530   // Replace the original operation to pad.
531   rewriter.replaceOp(op, newResults.getValue());
532   filter.replaceLinalgTransformationFilter(rewriter, paddedOp);
533   return success();
534 }
535 
536 /// Linalg tile and fuse tensor ops pattern.
537 mlir::linalg::LinalgTileAndFuseTensorOpsPattern::
538     LinalgTileAndFuseTensorOpsPattern(MLIRContext *context,
539                                       LinalgTilingAndFusionOptions options,
540                                       LinalgTransformationFilter filter,
541                                       PatternBenefit benefit)
542     : RewritePattern(MatchAnyOpTypeTag(), benefit, context), filter(filter),
543       options(options) {}
544 
545 mlir::linalg::LinalgTileAndFuseTensorOpsPattern::
546     LinalgTileAndFuseTensorOpsPattern(StringRef opName, MLIRContext *context,
547                                       LinalgTilingAndFusionOptions options,
548                                       LinalgTransformationFilter filter,
549                                       PatternBenefit benefit)
550     : RewritePattern(opName, benefit, context), filter(filter),
551       options(options) {}
552 
553 LogicalResult mlir::linalg::LinalgTileAndFuseTensorOpsPattern::matchAndRewrite(
554     Operation *op, PatternRewriter &rewriter) const {
555   LinalgOp rootOp = dyn_cast<LinalgOp>(op);
556   if (!rootOp)
557     return failure();
558   if (failed(filter.checkAndNotify(rewriter, op)))
559     return failure();
560 
561   // Check `tileSizes` contains a tile size for every `rootOp` loop dimension.
562   if (options.tileSizes.size() < rootOp.getNumLoops())
563     return rewriter.notifyMatchFailure(op, "expect #tile sizes >= #loops");
564 
565   // Check `tileInterchange` contains no entries or as many as `tileSizes`.
566   if (!options.tileInterchange.empty() &&
567       options.tileInterchange.size() != options.tileSizes.size())
568     return rewriter.notifyMatchFailure(
569         op, "expect the number of tile sizes and interchange dims to match");
570 
571   // Copy the `tileSizes` and `tileInterchange` prefixes needed for `rootOp`.
572   SmallVector<int64_t> rootTileSizes(options.tileSizes.begin(),
573                                      options.tileSizes.begin() +
574                                          rootOp.getNumLoops());
575   SmallVector<int64_t> rootInterchange =
576       options.tileInterchange.empty()
577           ? llvm::to_vector<6>(llvm::seq<int64_t>(0, rootOp.getNumLoops()))
578           : SmallVector<int64_t>(options.tileInterchange.begin(),
579                                  options.tileInterchange.begin() +
580                                      rootOp.getNumLoops());
581 
582   // Check `rootInterchange` is a permutation of the `rootOp` loop dimensions.
583   // It has to be a permutation since the tiling cannot tile the same loop
584   // dimension multiple times.
585   if (!isPermutation(rootInterchange))
586     return rewriter.notifyMatchFailure(
587         op, "expect the tile interchange permutes the root loops");
588 
589   // Tile `rootOp` and fuse its producers.
590   FailureOr<TileLoopNest> tileLoopNest = tileConsumerAndFuseProducers(
591       rewriter, rootOp, rootTileSizes, rootInterchange);
592   if (failed(tileLoopNest))
593     return rewriter.notifyMatchFailure(
594         op, "tileConsumerAndFuseProducers failed unexpectedly");
595 
596   // Replace all uses of the tiled loop operation.
597   rootOp->replaceAllUsesWith(tileLoopNest->getRootOpReplacementResults());
598 
599   // Apply the filter if specified.
600   for (LinalgOp linalgOp : tileLoopNest->getAllTiledAndFusedOps())
601     filter.replaceLinalgTransformationFilter(rewriter, linalgOp);
602   return failure();
603 }
604 
605 /// Linalg generic interchange pattern.
606 mlir::linalg::GenericOpInterchangePattern::GenericOpInterchangePattern(
607     MLIRContext *context, ArrayRef<unsigned> interchangeVector,
608     LinalgTransformationFilter filter, PatternBenefit benefit)
609     : OpRewritePattern(context, benefit), filter(filter),
610       interchangeVector(interchangeVector.begin(), interchangeVector.end()) {}
611 
612 LogicalResult mlir::linalg::GenericOpInterchangePattern::matchAndRewrite(
613     GenericOp genericOp, PatternRewriter &rewriter) const {
614   if (failed(filter.checkAndNotify(rewriter, genericOp)))
615     return failure();
616   if (failed(interchangeGenericOpPrecondition(genericOp, interchangeVector)))
617     return failure();
618 
619   // TODO: figure out how this interplays with named ops. In particular this
620   // should break the named op property.
621   rewriter.updateRootInPlace(genericOp, [&]() {
622     interchangeGenericOp(rewriter, genericOp, interchangeVector);
623     // New filter if specified.
624     filter.replaceLinalgTransformationFilter(rewriter, genericOp);
625   });
626   return success();
627 }
628 
629 /// Linalg generalization pattern.
630 mlir::linalg::LinalgGeneralizationPattern::LinalgGeneralizationPattern(
631     MLIRContext *context, LinalgTransformationFilter filter,
632     PatternBenefit benefit)
633     : RewritePattern(MatchAnyOpTypeTag(), benefit, context), filter(filter) {}
634 
635 mlir::linalg::LinalgGeneralizationPattern::LinalgGeneralizationPattern(
636     StringRef opName, MLIRContext *context, LinalgTransformationFilter filter,
637     PatternBenefit benefit)
638     : RewritePattern(opName, benefit, context, {}), filter(filter) {}
639 
640 LogicalResult mlir::linalg::LinalgGeneralizationPattern::matchAndRewrite(
641     Operation *op, PatternRewriter &rewriter) const {
642   if (failed(filter.checkAndNotify(rewriter, op)))
643     return failure();
644   if (failed(generalizeNamedOpPrecondition(op)))
645     return failure();
646 
647   GenericOp genericOp = generalizeNamedOp(rewriter, op);
648   rewriter.replaceOp(op, genericOp.getResults());
649   filter.replaceLinalgTransformationFilter(rewriter, genericOp);
650   return success();
651 }
652 
653 mlir::linalg::LinalgBasePromotionPattern::LinalgBasePromotionPattern(
654     MLIRContext *context, LinalgTransformationFilter filter,
655     LinalgPromotionOptions options, PatternBenefit benefit)
656     : RewritePattern(MatchAnyOpTypeTag(), benefit, context), filter(filter),
657       options(options) {}
658 
659 mlir::linalg::LinalgBasePromotionPattern::LinalgBasePromotionPattern(
660     StringRef opName, MLIRContext *context, LinalgPromotionOptions options,
661     LinalgTransformationFilter filter, PatternBenefit benefit)
662     : RewritePattern(opName, benefit, context, {}), filter(filter),
663       options(options) {}
664 
665 LogicalResult mlir::linalg::LinalgBasePromotionPattern::matchAndRewrite(
666     Operation *op, PatternRewriter &rewriter) const {
667   if (failed(filter.checkAndNotify(rewriter, op)))
668     return failure();
669   if (failed(promoteSubviewsPrecondition(op, options)))
670     return failure();
671 
672   // TODO: We cannot use root update here. This pattern is creating other ops,
673   // so if the promotion fails, those need to be cleaned up, which doesnt seem
674   // to be happening here. So to fail properly, we should be cloning the op and
675   // deleting the previous op. This needs more investigation.
676   rewriter.startRootUpdate(op);
677   Optional<LinalgOp> promotedOp = promoteSubViews(rewriter, op, options);
678   if (!promotedOp) {
679     rewriter.cancelRootUpdate(op);
680     return op->emitError("subview promotion failed");
681   }
682   rewriter.finalizeRootUpdate(op);
683   filter.replaceLinalgTransformationFilter(rewriter, op);
684   return success();
685 }
686 
687 mlir::linalg::LinalgBaseVectorizationPattern::LinalgBaseVectorizationPattern(
688     MLIRContext *context, LinalgTransformationFilter filter,
689     PatternBenefit benefit)
690     : RewritePattern(MatchAnyOpTypeTag(), benefit, context), filter(filter) {}
691 
692 mlir::linalg::LinalgBaseVectorizationPattern::LinalgBaseVectorizationPattern(
693     StringRef opName, MLIRContext *context, LinalgTransformationFilter filter,
694     PatternBenefit benefit)
695     : RewritePattern(opName, benefit, context, {}), filter(filter) {}
696 
697 LogicalResult mlir::linalg::LinalgBaseVectorizationPattern::matchAndRewrite(
698     Operation *op, PatternRewriter &rewriter) const {
699   LinalgOp linalgOp = dyn_cast<LinalgOp>(op);
700   if (!linalgOp)
701     return failure();
702   if (failed(filter.checkAndNotify(rewriter, linalgOp)))
703     return failure();
704   SmallVector<Value> newResults;
705   if (failed(vectorizeLinalgOp(rewriter, op, newResults)))
706     return failure();
707   if (!newResults.empty())
708     rewriter.replaceOp(op, newResults);
709   else
710     rewriter.eraseOp(op);
711   return success();
712 }
713 
714 LogicalResult mlir::linalg::applyStagedPatterns(
715     Operation *op, ArrayRef<FrozenRewritePatternSet> stage1Patterns,
716     const FrozenRewritePatternSet &stage2Patterns,
717     function_ref<LogicalResult(Operation *)> stage3Lambda) {
718   unsigned iteration = 0;
719   (void)iteration;
720   for (const auto &patterns : stage1Patterns) {
721     LLVM_DEBUG(DBGS() << "Before 1st stage, iter: " << ++iteration << "\n"
722                       << *op);
723     if (failed(applyPatternsAndFoldGreedily(op, patterns))) {
724       LLVM_DEBUG(DBGS() << "Underlying first stage rewrite did not converge");
725       return failure();
726     }
727     LLVM_DEBUG(DBGS() << "After 1st stage, iter: " << ++iteration << "\n"
728                       << *op);
729     if (failed(applyPatternsAndFoldGreedily(op, stage2Patterns))) {
730       LLVM_DEBUG(DBGS() << "Underlying 2nd stage rewrite did not converge");
731       return failure();
732     }
733     LLVM_DEBUG(DBGS() << "After 2nd stage, iter : " << iteration << "\n"
734                       << *op);
735     if (stage3Lambda) {
736       if (failed(stage3Lambda(op)))
737         return failure();
738       LLVM_DEBUG(DBGS() << "After 3rd stage, iter : " << iteration << "\n"
739                         << *op);
740     }
741   }
742   return success();
743 }
744 
745 static SmallVector<StringRef> getNParallelLoopsAttrs(unsigned nParallelLoops) {
746   return SmallVector<StringRef>(nParallelLoops, getParallelIteratorTypeName());
747 }
748 
749 /// Rewrite a PadTensorOp into a sequence of InitTensorOp, FillOp (to initialize
750 /// with pad_val) and GenericOp (to copy contents).
751 LogicalResult PadTensorOpTransformationPattern::matchAndRewrite(
752     linalg::PadTensorOp padOp, PatternRewriter &rewriter) const {
753 
754   auto inputShapedType = padOp.source().getType().cast<ShapedType>();
755   auto resultShapedType = padOp.result().getType().cast<ShapedType>();
756 
757   // Bail on non-static shapes.
758   if (!inputShapedType.hasStaticShape())
759     return failure();
760   if (!resultShapedType.hasStaticShape())
761     return failure();
762 
763   // Only support padding with a constant for now, i.e. either:
764   //   1. A BBarg from a different block.
765   //   2. A value defined outside of the current block.
766   Block &block = padOp.region().front();
767   auto yieldOp = cast<YieldOp>(block.getTerminator());
768   assert(yieldOp.getNumOperands() == 1 && "expected single operand yield");
769   Value padValue = yieldOp.values().front();
770   Operation *definingOp = padValue.getDefiningOp();
771   if (definingOp && definingOp->getBlock() == &block)
772     return failure();
773   if (!definingOp && padValue.cast<BlockArgument>().getOwner() == &block)
774     return failure();
775 
776   // Create tensor with the padded shape
777   Location loc = padOp.getLoc();
778   SmallVector<Value> indices(resultShapedType.getRank(),
779                              rewriter.create<arith::ConstantIndexOp>(loc, 0));
780   Value initTensor = rewriter.create<InitTensorOp>(
781       loc, resultShapedType.getShape(), resultShapedType.getElementType());
782 
783   // Initialize tensor with the pad value
784   Value tmpTensor =
785       rewriter.create<linalg::FillOp>(loc, padValue, initTensor).result();
786 
787   // Copy original contents into new tensor
788   // Uses linalg.generic, but could be done with tensor.insert_slice
789   SmallVector<AffineExpr, 4> outputExprs;
790   for (unsigned i = 0; i < resultShapedType.getRank(); ++i) {
791     outputExprs.push_back(getAffineDimExpr(i, rewriter.getContext()) +
792                           padOp.static_low()[i].cast<IntegerAttr>().getInt());
793   }
794 
795   SmallVector<AffineMap, 2> transferMaps = {
796       rewriter.getMultiDimIdentityMap(inputShapedType.getRank()),
797       AffineMap::get(resultShapedType.getRank(),
798                      /*symbolCount=*/0, outputExprs, rewriter.getContext())};
799 
800   rewriter.replaceOpWithNewOp<linalg::GenericOp>(
801       padOp, resultShapedType, padOp.source(), tmpTensor, transferMaps,
802       getNParallelLoopsAttrs(resultShapedType.getRank()),
803       [&](OpBuilder &nestedBuilder, Location nestedLoc, ValueRange args) {
804         nestedBuilder.create<linalg::YieldOp>(nestedLoc, args[0]);
805       });
806 
807   return success();
808 }
809 
810 /// Filling `dest` using FillOp constant padding value if possible.
811 /// Otherwise, generate a tensor::GenerateOp.
812 Value GeneralizePadTensorOpPattern::createFillOrGenerateOp(
813     PatternRewriter &rewriter, PadTensorOp padOp, Value dest,
814     const SmallVector<Value> &dynSizes) const {
815   auto padValue = padOp.getConstantPaddingValue();
816   if (padValue)
817     return rewriter.create<FillOp>(padOp.getLoc(), padValue, dest).result();
818 
819   // Fill could not be optimized: Lower to tensor::GenerateOp with region.
820   auto generateOp = rewriter.create<tensor::GenerateOp>(
821       padOp.getLoc(), padOp.getResultType(), dynSizes);
822   // Copy region to new op.
823   BlockAndValueMapping bvm;
824   padOp.region().cloneInto(&generateOp.getRegion(), bvm);
825   // Rewrite linalg::YieldOp to tensor::YieldOp.
826   OpBuilder::InsertionGuard guard(rewriter);
827   auto yieldOp =
828       dyn_cast<linalg::YieldOp>(generateOp.getRegion().front().getTerminator());
829   assert(yieldOp && "malformed PadTensorOp: expected YieldOp terminator");
830   assert(yieldOp.values().size() == 1);
831   rewriter.setInsertionPoint(yieldOp);
832   rewriter.replaceOpWithNewOp<tensor::YieldOp>(yieldOp, yieldOp.values()[0]);
833   return generateOp;
834 }
835 
836 LogicalResult
837 GeneralizePadTensorOpPattern::matchAndRewrite(PadTensorOp padOp,
838                                               PatternRewriter &rewriter) const {
839   // Given an OpFoldResult, return an index-typed value.
840   auto getIdxValue = [&](OpFoldResult ofr) {
841     if (auto val = ofr.dyn_cast<Value>())
842       return val;
843     return rewriter
844         .create<arith::ConstantIndexOp>(
845             padOp.getLoc(), ofr.get<Attribute>().cast<IntegerAttr>().getInt())
846         .getResult();
847   };
848 
849   auto resultType = padOp.getResultType();
850   // Compute size of InitTensorOp. Any combination of static/dynamic is
851   // supported.
852   SmallVector<Value> dynSizes;
853   SmallVector<int64_t> staticSizes;
854   for (unsigned dim = 0; dim < resultType.getRank(); ++dim) {
855     if (resultType.isDynamicDim(dim)) {
856       auto srcSize = rewriter.createOrFold<tensor::DimOp>(padOp.getLoc(),
857                                                           padOp.source(), dim);
858       // Add low and high padding value.
859       auto plusLow = rewriter.createOrFold<arith::AddIOp>(
860           padOp.getLoc(), srcSize, getIdxValue(padOp.getMixedLowPad()[dim]));
861       auto plusHigh = rewriter.createOrFold<arith::AddIOp>(
862           padOp.getLoc(), plusLow, getIdxValue(padOp.getMixedHighPad()[dim]));
863       dynSizes.push_back(plusHigh);
864     }
865     staticSizes.push_back(resultType.getDimSize(dim));
866   }
867 
868   // Init tensor and fill it with padding.
869   Value init = rewriter.create<InitTensorOp>(
870       padOp.getLoc(), dynSizes, staticSizes, resultType.getElementType());
871   Value fill = createFillOrGenerateOp(rewriter, padOp, init, dynSizes);
872 
873   // Try optimize the copy of source.
874   if (optimizeCopyFn && optimizeCopyFn(rewriter, padOp, fill).succeeded())
875     return success();
876 
877   // PadTensorOps cannot be optimized. Generate a InsertSliceOp instead
878   // for copying the PadOp source.
879   auto sourceType = padOp.getSourceType();
880   // Compute size of source of PadTensorOp.
881   SmallVector<OpFoldResult> srcSizes;
882   for (unsigned dim = 0; dim < sourceType.getRank(); ++dim) {
883     if (sourceType.isDynamicDim(dim)) {
884       srcSizes.push_back(rewriter.createOrFold<tensor::DimOp>(
885           padOp.getLoc(), padOp.source(), dim));
886     } else {
887       srcSizes.push_back(rewriter.getIndexAttr(sourceType.getDimSize(dim)));
888     }
889   }
890   // Strides of InsertSliceOp are all 1.
891   SmallVector<OpFoldResult> strides(sourceType.getRank(),
892                                     rewriter.getIndexAttr(1));
893   rewriter.replaceOpWithNewOp<tensor::InsertSliceOp>(
894       padOp, padOp.source(), fill, padOp.getMixedLowPad(), srcSizes, strides);
895 
896   return success();
897 }
898 
899 LogicalResult ExtractSliceOfPadTensorSwapPattern::matchAndRewrite(
900     tensor::ExtractSliceOp sliceOp, PatternRewriter &rewriter) const {
901   auto padOp = sliceOp.source().getDefiningOp<PadTensorOp>();
902   if (!padOp)
903     return failure();
904   // Only unit stride supported.
905   if (!sliceOp.hasUnitStride())
906     return failure();
907 
908   Operation *tiledPadOp =
909       padOp
910           .getTiledImplementation(
911               rewriter, /*dest=*/ValueRange{}, sliceOp.getMixedOffsets(),
912               sliceOp.getMixedSizes(), /*tileDestOperands=*/false)
913           .front();
914   // All shapes are static and the data source is actually used. Rewrite into
915   // pad_tensor(subtensor(x)).
916   rewriter.replaceOp(sliceOp, tiledPadOp->getResults());
917   return success();
918 }
919 
920 namespace {
921 // The following are patterns for downscaling convolution ops with size-1
922 // window dimensions.
923 //
924 // Note that we'd eventually want to write such transformations in a generic
925 // way, e.g., converting to linalg.generic, removing the size-1 dimensions,
926 // and then turning back to named ops. But for now it's fine to have a few
927 // patterns matching special ops to get started.
928 
929 /// Rewrites 2-D convolution ops with size-1 window dimensions into 1-D
930 /// convolution ops.
931 struct DownscaleSizeOneWindowed2DConvolution final
932     : public OpRewritePattern<Conv2DNhwcHwcfOp> {
933   DownscaleSizeOneWindowed2DConvolution(
934       MLIRContext *context,
935       LinalgTransformationFilter filter = LinalgTransformationFilter(),
936       PatternBenefit benefit = 1)
937       : OpRewritePattern<Conv2DNhwcHwcfOp>(context, benefit), filter(filter) {}
938 
939   LogicalResult matchAndRewrite(linalg::Conv2DNhwcHwcfOp convOp,
940                                 PatternRewriter &rewriter) const override {
941     if (failed(filter.checkAndNotify(rewriter, convOp)))
942       return failure();
943     if (convOp.hasBufferSemantics())
944       return failure(); // To be implemented
945 
946     Value input = convOp.inputs().front();
947     Value kernel = convOp.inputs().back();
948     Value output = convOp.outputs().front();
949 
950     auto inputType = input.getType().dyn_cast<RankedTensorType>();
951     auto kernelType = kernel.getType().dyn_cast<RankedTensorType>();
952     auto outputType = output.getType().dyn_cast<RankedTensorType>();
953 
954     auto kernelShape = kernelType.getShape();
955     auto outputShape = outputType.getShape();
956 
957     // Only handle the case where at least one of the window dimensions is
958     // of size 1. Other cases can rely on tiling to reduce to such cases.
959     int64_t khSize = kernelShape[0], kwSize = kernelShape[1];
960     int64_t ohSize = outputShape[1], owSize = outputShape[2];
961     bool removeH = (khSize == 1 && ohSize == 1);
962     bool removeW = (kwSize == 1 && owSize == 1);
963     if (!removeH && !removeW)
964       return failure();
965 
966     // Get new shapes and types for all operands by removing the size-1
967     // dimension.
968     using RTTBuilder = RankedTensorType::Builder;
969     RankedTensorType newInputType =
970         RTTBuilder(inputType).dropDim((removeH ? 1 : 2));
971     RankedTensorType newKernelType =
972         RTTBuilder(kernelType).dropDim((removeH ? 0 : 1));
973     RankedTensorType newOutputType =
974         RTTBuilder(outputType).dropDim(removeH ? 1 : 2);
975 
976     // Rank-reduce operands.
977     Location loc = convOp.getLoc();
978     Value newInput = tensor::createCanonicalRankReducingExtractSliceOp(
979         rewriter, loc, input, newInputType);
980     Value newKernel = tensor::createCanonicalRankReducingExtractSliceOp(
981         rewriter, loc, kernel, newKernelType);
982     Value newOutput = tensor::createCanonicalRankReducingExtractSliceOp(
983         rewriter, loc, output, newOutputType);
984 
985     // Rank-reduce strides and dilations too.
986     // TODO: dropDim 1-liner helper.
987     auto strides = llvm::to_vector<4>(convOp.strides().getValues<int64_t>());
988     strides.erase(strides.begin() + (removeH ? 0 : 1));
989     auto stridesAttr = rewriter.getI64VectorAttr(strides);
990 
991     auto dilations =
992         llvm::to_vector<4>(convOp.dilations().getValues<int64_t>());
993     dilations.erase(dilations.begin() + (removeH ? 0 : 1));
994     auto dilationsAttr = rewriter.getI64VectorAttr(dilations);
995 
996     auto conv1DOp = rewriter.create<linalg::Conv1DNwcWcfOp>(
997         loc, newOutputType, ValueRange{newInput, newKernel},
998         ValueRange{newOutput}, stridesAttr, dilationsAttr);
999 
1000     // Insert back.
1001     Value inserted = tensor::createCanonicalRankReducingInsertSliceOp(
1002         rewriter, loc, conv1DOp.getResult(0), output);
1003     rewriter.replaceOp(convOp, inserted);
1004 
1005     filter.replaceLinalgTransformationFilter(rewriter, conv1DOp);
1006     return success();
1007   };
1008 
1009 private:
1010   /// LinalgTransformMarker handles special attribute manipulations.
1011   LinalgTransformationFilter filter;
1012 };
1013 
1014 /// Rewrites 2-D depthwise convolution ops with size-1 (w, kw) or (h, kh)
1015 /// dimensions into 1-D depthwise convolution ops.
1016 struct DownscaleDepthwiseConv2DNhwcHwcOp final
1017     : public OpRewritePattern<DepthwiseConv2DNhwcHwcOp> {
1018   DownscaleDepthwiseConv2DNhwcHwcOp(
1019       MLIRContext *context,
1020       LinalgTransformationFilter filter = LinalgTransformationFilter(),
1021       PatternBenefit benefit = 1)
1022       : OpRewritePattern<DepthwiseConv2DNhwcHwcOp>(context, benefit),
1023         filter(filter) {}
1024 
1025   LogicalResult matchAndRewrite(DepthwiseConv2DNhwcHwcOp convOp,
1026                                 PatternRewriter &rewriter) const override {
1027     if (failed(filter.checkAndNotify(rewriter, convOp)))
1028       return failure();
1029     if (convOp.hasBufferSemantics())
1030       return failure(); // To be implemented
1031 
1032     Value input = convOp.inputs().front();
1033     Value kernel = convOp.inputs().back();
1034     Value output = convOp.outputs().front();
1035 
1036     auto inputType = input.getType().dyn_cast<RankedTensorType>();
1037     auto kernelType = kernel.getType().dyn_cast<RankedTensorType>();
1038     auto outputType = output.getType().dyn_cast<RankedTensorType>();
1039 
1040     auto kernelShape = kernelType.getShape();
1041     auto outputShape = outputType.getShape();
1042 
1043     // Only handle the case where at least one of the window dimensions is
1044     // of size 1. Other cases can rely on tiling to reduce to such cases.
1045     int64_t khSize = kernelShape[0], kwSize = kernelShape[1];
1046     int64_t ohSize = outputShape[1], owSize = outputShape[2];
1047     bool removeH = (khSize == 1 && ohSize == 1);
1048     bool removeW = (kwSize == 1 && owSize == 1);
1049     if (!removeH && !removeW)
1050       return failure();
1051 
1052     // Get new shapes and types for all operands by removing the size-1
1053     // dimension.
1054     using RTTBuilder = RankedTensorType::Builder;
1055     RankedTensorType newInputType =
1056         RTTBuilder(inputType).dropDim((removeH ? 1 : 2));
1057     RankedTensorType newKernelType =
1058         RTTBuilder(kernelType).dropDim((removeH ? 0 : 1));
1059     RankedTensorType newOutputType =
1060         RTTBuilder(outputType).dropDim(removeH ? 1 : 2);
1061 
1062     // Rank-reduce operands.
1063     Location loc = convOp.getLoc();
1064     Value newInput = tensor::createCanonicalRankReducingExtractSliceOp(
1065         rewriter, loc, input, newInputType);
1066     Value newKernel = tensor::createCanonicalRankReducingExtractSliceOp(
1067         rewriter, loc, kernel, newKernelType);
1068     Value newOutput = tensor::createCanonicalRankReducingExtractSliceOp(
1069         rewriter, loc, output, newOutputType);
1070 
1071     // Rank-reduce strides and dilations too.
1072     // TODO: dropDim 1-liner helper.
1073     auto strides = llvm::to_vector<4>(convOp.strides().getValues<int64_t>());
1074     strides.erase(strides.begin() + (removeH ? 0 : 1));
1075     auto stridesAttr = rewriter.getI64VectorAttr(strides);
1076 
1077     auto dilations =
1078         llvm::to_vector<4>(convOp.dilations().getValues<int64_t>());
1079     dilations.erase(dilations.begin() + (removeH ? 0 : 1));
1080     auto dilationsAttr = rewriter.getI64VectorAttr(dilations);
1081 
1082     auto conv1DOp = rewriter.create<DepthwiseConv1DNwcWcOp>(
1083         loc, newOutputType, ValueRange{newInput, newKernel},
1084         ValueRange{newOutput}, stridesAttr, dilationsAttr);
1085 
1086     // Insert back.
1087     Value inserted = tensor::createCanonicalRankReducingInsertSliceOp(
1088         rewriter, loc, conv1DOp.getResult(0), output);
1089     rewriter.replaceOp(convOp, inserted);
1090 
1091     filter.replaceLinalgTransformationFilter(rewriter, conv1DOp);
1092     return success();
1093   };
1094 
1095 private:
1096   /// LinalgTransformMarker handles special attribute manipulations.
1097   LinalgTransformationFilter filter;
1098 };
1099 
1100 } // namespace
1101 
1102 void linalg::populateDecomposeConvolutionPatterns(
1103     RewritePatternSet &patterns, LinalgTransformationFilter filter,
1104     PatternBenefit benefit) {
1105   patterns.add<DownscaleSizeOneWindowed2DConvolution,
1106                DownscaleDepthwiseConv2DNhwcHwcOp>(patterns.getContext(), filter,
1107                                                   benefit);
1108 }
1109