1 //===- VectorUnrollDistribute.cpp - patterns to do vector unrolling -------===//
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 patterns to do vector unrolling and vector distribution.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "mlir/Dialect/Affine/IR/AffineOps.h"
14 #include "mlir/Dialect/Utils/IndexingUtils.h"
15 #include "mlir/Dialect/Vector/Transforms/VectorTransforms.h"
16 #include "mlir/IR/ImplicitLocOpBuilder.h"
17 #include "mlir/Interfaces/VectorInterfaces.h"
18 #include "mlir/Support/MathExtras.h"
19 #include "llvm/ADT/MapVector.h"
20 #include "llvm/ADT/STLExtras.h"
21 #include <numeric>
22 
23 #define DEBUG_TYPE "vector-unrolling"
24 
25 using namespace mlir;
26 using namespace mlir::vector;
27 
28 /// During unrolling from `originalShape` to `targetShape` return the offset for
29 /// the slice `index`.
30 static SmallVector<int64_t, 4> getVectorOffset(ArrayRef<int64_t> originalShape,
31                                                ArrayRef<int64_t> targetShape,
32                                                int64_t index) {
33   SmallVector<int64_t, 4> dstSliceStrides =
34       computeStrides(originalShape, targetShape);
35   SmallVector<int64_t, 4> vectorOffsets = delinearize(dstSliceStrides, index);
36   SmallVector<int64_t, 4> elementOffsets =
37       computeElementOffsetsFromVectorSliceOffsets(targetShape, vectorOffsets);
38   return elementOffsets;
39 }
40 
41 /// A functor that accomplishes the same thing as `getVectorOffset` but allows
42 /// for reordering the traversal of the dimensions. The order of traversal is
43 /// given in "for loop order" (outer to inner).
44 namespace {
45 class DecomposeShapeIterator {
46 private:
47   SmallVector<int64_t, 4> vectorShape;
48   SmallVector<int64_t> loopOrder;
49   SmallVector<int64_t> sliceStrides;
50   int64_t maxIndexVal{1};
51 
52 public:
53   DecomposeShapeIterator(ArrayRef<int64_t> originalShape,
54                          ArrayRef<int64_t> targetShape,
55                          ArrayRef<int64_t> loopOrder)
56       : vectorShape(targetShape.begin(), targetShape.end()),
57         loopOrder(loopOrder.begin(), loopOrder.end()),
58         sliceStrides(originalShape.size()) {
59     assert(originalShape.size() == targetShape.size());
60     assert(loopOrder.size() == targetShape.size());
61 
62     // Compute the count for each dimension.
63     SmallVector<int64_t> sliceDimCounts(originalShape.size());
64     for (unsigned r = 0; r < originalShape.size(); ++r) {
65       sliceDimCounts[r] = ceilDiv(originalShape[r], targetShape[r]);
66       maxIndexVal *= sliceDimCounts[r];
67     }
68 
69     // Reversing "loop order" gives dimensions from fastest varying to slowest
70     // varying (smallest stride to largest stride).
71     int64_t accum = 1;
72     for (auto idx : llvm::reverse(loopOrder)) {
73       sliceStrides[idx] = accum;
74       accum *= sliceDimCounts[idx];
75     }
76   }
77 
78   // Turn the linear index into a d-tuple based on units of vectors of size
79   // `vectorShape`. The linear index is assumed to represent traversal of the
80   // dimensions based on `order`.
81   SmallVector<int64_t> delinearize(int64_t index) const {
82     // Traverse in for loop order (largest stride to smallest stride).
83     SmallVector<int64_t> vectorOffsets(sliceStrides.size());
84     for (auto idx : loopOrder) {
85       vectorOffsets[idx] = index / sliceStrides[idx];
86       index %= sliceStrides[idx];
87     }
88     return vectorOffsets;
89   }
90 
91   int64_t maxIndex() const { return maxIndexVal; }
92 
93   /// Return the offset within d-tuple based on the ordering given by
94   /// `loopOrder`.
95   SmallVector<int64_t> getVectorOffset(int64_t index) const {
96     SmallVector<int64_t> vectorOffsets = delinearize(index);
97     SmallVector<int64_t> elementOffsets =
98         computeElementOffsetsFromVectorSliceOffsets(vectorShape, vectorOffsets);
99     return elementOffsets;
100   }
101 };
102 } // namespace
103 
104 /// Compute the indices of the slice `index` for a tranfer op.
105 static SmallVector<Value> sliceTransferIndices(ArrayRef<int64_t> elementOffsets,
106                                                ArrayRef<Value> indices,
107                                                AffineMap permutationMap,
108                                                Location loc,
109                                                OpBuilder &builder) {
110   MLIRContext *ctx = builder.getContext();
111   auto isBroadcast = [](AffineExpr expr) {
112     if (auto constExpr = expr.dyn_cast<AffineConstantExpr>())
113       return constExpr.getValue() == 0;
114     return false;
115   };
116   // Compute 'sliceIndices' by adding 'sliceOffsets[i]' to 'indices[i]'.
117   SmallVector<Value> slicedIndices(indices.begin(), indices.end());
118   for (const auto &dim : llvm::enumerate(permutationMap.getResults())) {
119     if (isBroadcast(dim.value()))
120       continue;
121     unsigned pos = dim.value().cast<AffineDimExpr>().getPosition();
122     auto expr = getAffineDimExpr(0, builder.getContext()) +
123                 getAffineConstantExpr(elementOffsets[dim.index()], ctx);
124     auto map = AffineMap::get(/*dimCount=*/1, /*symbolCount=*/0, expr);
125     slicedIndices[pos] = builder.create<AffineApplyOp>(loc, map, indices[pos]);
126   }
127   return slicedIndices;
128 }
129 
130 // Clones `op` into a new operations that takes `operands` and returns
131 // `resultTypes`.
132 static Operation *cloneOpWithOperandsAndTypes(OpBuilder &builder, Location loc,
133                                               Operation *op,
134                                               ArrayRef<Value> operands,
135                                               ArrayRef<Type> resultTypes) {
136   return builder.create(loc, op->getName().getIdentifier(), operands,
137                         resultTypes, op->getAttrs());
138 }
139 
140 /// Return the target shape for unrolling for the given `op`. Return llvm::None
141 /// if the op shouldn't be or cannot be unrolled.
142 static Optional<SmallVector<int64_t, 4>>
143 getTargetShape(const vector::UnrollVectorOptions &options, Operation *op) {
144   if (options.filterConstraint && failed(options.filterConstraint(op)))
145     return llvm::None;
146   assert(options.nativeShape &&
147          "vector unrolling expects the native shape or native"
148          "shape call back function to be set");
149   auto unrollableVectorOp = dyn_cast<VectorUnrollOpInterface>(op);
150   if (!unrollableVectorOp)
151     return llvm::None;
152   auto maybeUnrollShape = unrollableVectorOp.getShapeForUnroll();
153   if (!maybeUnrollShape)
154     return llvm::None;
155   Optional<SmallVector<int64_t, 4>> targetShape = options.nativeShape(op);
156   if (!targetShape)
157     return llvm::None;
158   auto maybeShapeRatio = shapeRatio(*maybeUnrollShape, *targetShape);
159   if (!maybeShapeRatio ||
160       llvm::all_of(*maybeShapeRatio, [](int64_t v) { return v == 1; }))
161     return llvm::None;
162   return targetShape;
163 }
164 
165 static SmallVector<int64_t>
166 getUnrollOrder(unsigned numLoops, Operation *op,
167                const vector::UnrollVectorOptions &options) {
168   SmallVector<int64_t> loopOrder =
169       llvm::to_vector(llvm::seq<int64_t>(0, static_cast<int64_t>(numLoops)));
170   if (options.traversalOrderCallback != nullptr) {
171     Optional<SmallVector<int64_t>> order = options.traversalOrderCallback(op);
172     if (order) {
173       loopOrder = std::move(*order);
174     }
175   }
176   return loopOrder;
177 }
178 
179 namespace {
180 
181 struct UnrollTransferReadPattern
182     : public OpRewritePattern<vector::TransferReadOp> {
183   UnrollTransferReadPattern(MLIRContext *context,
184                             const vector::UnrollVectorOptions &options)
185       : OpRewritePattern<vector::TransferReadOp>(context, /*benefit=*/1),
186         options(options) {}
187   LogicalResult matchAndRewrite(vector::TransferReadOp readOp,
188                                 PatternRewriter &rewriter) const override {
189     // TODO: support 0-d corner case.
190     if (readOp.getTransferRank() == 0)
191       return failure();
192     if (readOp.getMask())
193       return failure();
194     auto targetShape = getTargetShape(options, readOp);
195     if (!targetShape)
196       return failure();
197     auto sourceVectorType = readOp.getVectorType();
198     SmallVector<int64_t, 4> strides(targetShape->size(), 1);
199     Location loc = readOp.getLoc();
200     ArrayRef<int64_t> originalSize = readOp.getVectorType().getShape();
201 
202     // Prepare the result vector;
203     Value result = rewriter.create<arith::ConstantOp>(
204         loc, sourceVectorType, rewriter.getZeroAttr(sourceVectorType));
205     auto targetType =
206         VectorType::get(*targetShape, sourceVectorType.getElementType());
207     SmallVector<Value, 4> originalIndices(readOp.getIndices().begin(),
208                                           readOp.getIndices().end());
209 
210     SmallVector<int64_t> loopOrder =
211         getUnrollOrder(originalSize.size(), readOp, options);
212     DecomposeShapeIterator indexToOffsets(originalSize, *targetShape,
213                                           loopOrder);
214     for (int64_t i = 0; i < indexToOffsets.maxIndex(); i++) {
215       SmallVector<int64_t, 4> elementOffsets =
216           indexToOffsets.getVectorOffset(i);
217       SmallVector<Value, 4> indices =
218           sliceTransferIndices(elementOffsets, originalIndices,
219                                readOp.getPermutationMap(), loc, rewriter);
220       auto slicedRead = rewriter.create<vector::TransferReadOp>(
221           loc, targetType, readOp.getSource(), indices,
222           readOp.getPermutationMapAttr(), readOp.getPadding(), readOp.getMask(),
223           readOp.getInBoundsAttr());
224 
225       result = rewriter.create<vector::InsertStridedSliceOp>(
226           loc, slicedRead, result, elementOffsets, strides);
227     }
228     rewriter.replaceOp(readOp, result);
229     return success();
230   }
231 
232 private:
233   vector::UnrollVectorOptions options;
234 };
235 
236 struct UnrollTransferWritePattern
237     : public OpRewritePattern<vector::TransferWriteOp> {
238   UnrollTransferWritePattern(MLIRContext *context,
239                              const vector::UnrollVectorOptions &options)
240       : OpRewritePattern<vector::TransferWriteOp>(context, /*benefit=*/1),
241         options(options) {}
242   LogicalResult matchAndRewrite(vector::TransferWriteOp writeOp,
243                                 PatternRewriter &rewriter) const override {
244     // TODO: support 0-d corner case.
245     if (writeOp.getTransferRank() == 0)
246       return failure();
247 
248     if (writeOp.getMask())
249       return failure();
250     auto targetShape = getTargetShape(options, writeOp);
251     if (!targetShape)
252       return failure();
253     auto sourceVectorType = writeOp.getVectorType();
254     SmallVector<int64_t, 4> strides(targetShape->size(), 1);
255     Location loc = writeOp.getLoc();
256     ArrayRef<int64_t> originalSize = sourceVectorType.getShape();
257     SmallVector<Value, 4> originalIndices(writeOp.getIndices().begin(),
258                                           writeOp.getIndices().end());
259 
260     SmallVector<int64_t> loopOrder =
261         getUnrollOrder(originalSize.size(), writeOp, options);
262     DecomposeShapeIterator indexToOffsets(originalSize, *targetShape,
263                                           loopOrder);
264     Value resultTensor;
265     for (int64_t i = 0; i < indexToOffsets.maxIndex(); i++) {
266       SmallVector<int64_t, 4> elementOffsets =
267           indexToOffsets.getVectorOffset(i);
268       Value slicedVector = rewriter.create<vector::ExtractStridedSliceOp>(
269           loc, writeOp.getVector(), elementOffsets, *targetShape, strides);
270       SmallVector<Value, 4> indices =
271           sliceTransferIndices(elementOffsets, originalIndices,
272                                writeOp.getPermutationMap(), loc, rewriter);
273       Operation *slicedWrite = rewriter.create<vector::TransferWriteOp>(
274           loc, slicedVector, resultTensor ? resultTensor : writeOp.getSource(),
275           indices, writeOp.getPermutationMapAttr(), writeOp.getInBoundsAttr());
276       // For the tensor case update the destination for the next transfer write.
277       if (!slicedWrite->getResults().empty())
278         resultTensor = slicedWrite->getResult(0);
279     }
280     if (resultTensor)
281       rewriter.replaceOp(writeOp, resultTensor);
282     else
283       rewriter.eraseOp(writeOp);
284     return success();
285   }
286 
287 private:
288   vector::UnrollVectorOptions options;
289 };
290 
291 struct OffsetMapInfo {
292   static SmallVector<int64_t> getEmptyKey() { return {int64_t(-1)}; }
293 
294   static SmallVector<int64_t> getTombstoneKey() { return {int64_t(-2)}; }
295 
296   static unsigned getHashValue(const SmallVector<int64_t> &v) {
297     return static_cast<unsigned>(llvm::hash_combine_range(v.begin(), v.end()));
298   }
299 
300   static bool isEqual(const SmallVector<int64_t> &lhs,
301                       const SmallVector<int64_t> &rhs) {
302     return lhs == rhs;
303   }
304 };
305 
306 struct UnrollContractionPattern
307     : public OpRewritePattern<vector::ContractionOp> {
308   UnrollContractionPattern(MLIRContext *context,
309                            const vector::UnrollVectorOptions &options)
310       : OpRewritePattern<vector::ContractionOp>(context, /*benefit=*/1),
311         options(options) {}
312 
313   LogicalResult matchAndRewrite(vector::ContractionOp contractOp,
314                                 PatternRewriter &rewriter) const override {
315     auto targetShape = getTargetShape(options, contractOp);
316     if (!targetShape)
317       return failure();
318     auto dstVecType = contractOp.getResultType().cast<VectorType>();
319     SmallVector<int64_t, 4> originalSize = *contractOp.getShapeForUnroll();
320 
321     Location loc = contractOp.getLoc();
322     unsigned accIndex = vector::ContractionOp::getAccOperandIndex();
323     AffineMap dstAffineMap = contractOp.getIndexingMaps()[accIndex];
324     llvm::MapVector<
325         SmallVector<int64_t>, Value,
326         llvm::DenseMap<SmallVector<int64_t>, unsigned, OffsetMapInfo>>
327         accCache;
328 
329     SmallVector<int64_t> loopOrder = getUnrollOrder(
330         contractOp.getIteratorTypes().size(), contractOp, options);
331     DecomposeShapeIterator indexToOffsets(originalSize, *targetShape,
332                                           loopOrder);
333     const int64_t sliceCount = indexToOffsets.maxIndex();
334     for (int64_t i = 0; i < sliceCount; i++) {
335       SmallVector<int64_t, 4> offsets = indexToOffsets.getVectorOffset(i);
336       SmallVector<Value, 4> slicesOperands(contractOp.getNumOperands());
337 
338       // Helper to coompute the new shape of each operand and extract the slice.
339       auto extractOperand = [&](unsigned index, Value operand,
340                                 AffineMap permutationMap,
341                                 ArrayRef<int64_t> operandOffets) {
342         SmallVector<int64_t> operandShape = applyPermutationMap(
343             permutationMap, ArrayRef<int64_t>(*targetShape));
344         SmallVector<int64_t, 4> operandStrides(operandOffets.size(), 1);
345         slicesOperands[index] = rewriter.create<vector::ExtractStridedSliceOp>(
346             loc, operand, operandOffets, operandShape, operandStrides);
347       };
348 
349       // Extract the new lhs operand.
350       AffineMap lhsPermutationMap = contractOp.getIndexingMaps()[0];
351       SmallVector<int64_t> lhsOffets =
352           applyPermutationMap(lhsPermutationMap, ArrayRef<int64_t>(offsets));
353       extractOperand(0, contractOp.getLhs(), lhsPermutationMap, lhsOffets);
354       // If there is a mask associated to lhs, extract it as well.
355       if (slicesOperands.size() > 3)
356         extractOperand(3, contractOp.getMasks()[0], lhsPermutationMap,
357                        lhsOffets);
358 
359       // Extract the new rhs operand.
360       AffineMap rhsPermutationMap = contractOp.getIndexingMaps()[1];
361       SmallVector<int64_t> rhsOffets =
362           applyPermutationMap(rhsPermutationMap, ArrayRef<int64_t>(offsets));
363       extractOperand(1, contractOp.getRhs(), rhsPermutationMap, rhsOffets);
364       // If there is a mask associated to rhs, extract it as well.
365       if (slicesOperands.size() > 4)
366         extractOperand(4, contractOp.getMasks()[1], rhsPermutationMap,
367                        rhsOffets);
368 
369       AffineMap accPermutationMap = contractOp.getIndexingMaps()[2];
370       SmallVector<int64_t> accOffets =
371           applyPermutationMap(accPermutationMap, ArrayRef<int64_t>(offsets));
372       // If a version of the accumulator has already been computed, use it
373       // otherwise extract the first version from the original operand.
374       auto accIt = accCache.find(accOffets);
375       if (accIt != accCache.end())
376         slicesOperands[2] = accIt->second;
377       else
378         extractOperand(2, contractOp.getAcc(), accPermutationMap, accOffets);
379 
380       SmallVector<int64_t> dstShape =
381           applyPermutationMap(dstAffineMap, ArrayRef<int64_t>(*targetShape));
382       auto targetType = VectorType::get(dstShape, dstVecType.getElementType());
383       Operation *newOp = cloneOpWithOperandsAndTypes(
384           rewriter, loc, contractOp, slicesOperands, targetType);
385 
386       SmallVector<int64_t> dstOffets =
387           applyPermutationMap(dstAffineMap, ArrayRef<int64_t>(offsets));
388       // Save the accumulated value untill all the loops are unrolled since
389       // reduction loop keep updating the accumulator.
390       accCache[dstOffets] = newOp->getResult(0);
391     }
392     // Assemble back the accumulator into a single vector.
393     Value result = rewriter.create<arith::ConstantOp>(
394         loc, dstVecType, rewriter.getZeroAttr(dstVecType));
395     for (const auto &it : accCache) {
396       SmallVector<int64_t> dstStrides(it.first.size(), 1);
397       result = rewriter.create<vector::InsertStridedSliceOp>(
398           loc, it.second, result, it.first, dstStrides);
399     }
400     rewriter.replaceOp(contractOp, result);
401     return success();
402   }
403 
404 private:
405   vector::UnrollVectorOptions options;
406 };
407 
408 struct UnrollMultiReductionPattern
409     : public OpRewritePattern<vector::MultiDimReductionOp> {
410   UnrollMultiReductionPattern(MLIRContext *context,
411                               const vector::UnrollVectorOptions &options)
412       : OpRewritePattern<vector::MultiDimReductionOp>(context, /*benefit=*/1),
413         options(options) {}
414 
415   LogicalResult matchAndRewrite(vector::MultiDimReductionOp reductionOp,
416                                 PatternRewriter &rewriter) const override {
417     Optional<SmallVector<int64_t, 4>> targetShape =
418         getTargetShape(options, reductionOp);
419     if (!targetShape)
420       return failure();
421     SmallVector<int64_t, 4> originalSize = *reductionOp.getShapeForUnroll();
422     SmallVector<int64_t, 4> ratio = *shapeRatio(originalSize, *targetShape);
423     llvm::MapVector<
424         SmallVector<int64_t>, Value,
425         llvm::DenseMap<SmallVector<int64_t>, unsigned, OffsetMapInfo>>
426         accCache;
427     // Compute shape ratio of 'shape' and 'sizes'.
428     int64_t sliceCount = computeMaxLinearIndex(ratio);
429     Location loc = reductionOp.getLoc();
430     for (int64_t i = 0; i < sliceCount; i++) {
431       SmallVector<int64_t, 4> offsets =
432           getVectorOffset(originalSize, *targetShape, i);
433 
434       SmallVector<int64_t, 4> operandStrides(offsets.size(), 1);
435       Value slicedOperand = rewriter.create<vector::ExtractStridedSliceOp>(
436           loc, reductionOp.getOperand(), offsets, *targetShape, operandStrides);
437 
438       SmallVector<int64_t> dstShape;
439       SmallVector<int64_t> destOffset;
440       for (size_t i : llvm::seq(size_t(0), targetShape->size())) {
441         if (!reductionOp.isReducedDim(i)) {
442           destOffset.push_back(offsets[i]);
443           dstShape.push_back((*targetShape)[i]);
444         }
445       }
446       auto targetType = VectorType::get(
447           dstShape, reductionOp.getSourceVectorType().getElementType());
448       Operation *newOp = cloneOpWithOperandsAndTypes(rewriter, loc, reductionOp,
449                                                      slicedOperand, targetType);
450       Value result = newOp->getResult(0);
451       // Save the accumulated value until all the loops are unrolled since
452       // reduction loop keeps updating the accumulator.
453       auto accIt = accCache.find(destOffset);
454       if (accIt != accCache.end())
455         result = makeArithReduction(rewriter, loc, reductionOp.getKind(),
456                                     result, accIt->second);
457       accCache[destOffset] = result;
458     }
459     // Assemble back the accumulator into a single vector.
460     Value result = rewriter.create<arith::ConstantOp>(
461         loc, reductionOp.getDestType(),
462         rewriter.getZeroAttr(reductionOp.getDestType()));
463     for (const auto &it : accCache) {
464       SmallVector<int64_t> dstStrides(it.first.size(), 1);
465       result = rewriter.create<vector::InsertStridedSliceOp>(
466           loc, it.second, result, it.first, dstStrides);
467     }
468     rewriter.replaceOp(reductionOp, result);
469     return success();
470   }
471 
472 private:
473   vector::UnrollVectorOptions options;
474 };
475 
476 struct UnrollElementwisePattern : public RewritePattern {
477   UnrollElementwisePattern(MLIRContext *context,
478                            const vector::UnrollVectorOptions &options)
479       : RewritePattern(MatchAnyOpTypeTag(), /*benefit=*/1, context),
480         options(options) {}
481   LogicalResult matchAndRewrite(Operation *op,
482                                 PatternRewriter &rewriter) const override {
483     if (!OpTrait::hasElementwiseMappableTraits(op) || op->getNumResults() != 1)
484       return failure();
485     auto targetShape = getTargetShape(options, op);
486     if (!targetShape)
487       return failure();
488     auto dstVecType = op->getResult(0).getType().cast<VectorType>();
489     SmallVector<int64_t, 4> originalSize =
490         *cast<VectorUnrollOpInterface>(op).getShapeForUnroll();
491     SmallVector<int64_t, 4> ratio = *shapeRatio(originalSize, *targetShape);
492     int64_t sliceCount = computeMaxLinearIndex(ratio);
493     Location loc = op->getLoc();
494     // Prepare the result vector.
495     Value result = rewriter.create<arith::ConstantOp>(
496         loc, dstVecType, rewriter.getZeroAttr(dstVecType));
497     SmallVector<int64_t, 4> strides(targetShape->size(), 1);
498     VectorType newVecType =
499         VectorType::get(*targetShape, dstVecType.getElementType());
500     for (int64_t i = 0; i < sliceCount; i++) {
501       SmallVector<int64_t, 4> offsets =
502           getVectorOffset(originalSize, *targetShape, i);
503       SmallVector<Value, 4> extractOperands;
504       for (OpOperand &operand : op->getOpOperands()) {
505         auto vecType = operand.get().getType().template dyn_cast<VectorType>();
506         if (!vecType) {
507           extractOperands.push_back(operand.get());
508           continue;
509         }
510         extractOperands.push_back(
511             rewriter.create<vector::ExtractStridedSliceOp>(
512                 loc, operand.get(), offsets, *targetShape, strides));
513       }
514       Operation *newOp = cloneOpWithOperandsAndTypes(
515           rewriter, loc, op, extractOperands, newVecType);
516       result = rewriter.create<vector::InsertStridedSliceOp>(
517           loc, newOp->getResult(0), result, offsets, strides);
518     }
519     rewriter.replaceOp(op, result);
520     return success();
521   }
522 
523 private:
524   vector::UnrollVectorOptions options;
525 };
526 
527 /// Canonicalize an extract_map using the result of a pointwise operation.
528 /// Transforms:
529 /// %v = arith.addf %a, %b : vector32xf32>
530 /// %dv = vector.extract_map %v[%id] : vector<32xf32> to vector<1xf32>
531 /// to:
532 /// %da = vector.extract_map %a[%id] : vector<32xf32> to vector<1xf32>
533 /// %db = vector.extract_map %a[%id] : vector<32xf32> to vector<1xf32>
534 /// %dv = arith.addf %da, %db : vector<1xf32>
535 struct PointwiseExtractPattern : public OpRewritePattern<vector::ExtractMapOp> {
536   using OpRewritePattern<vector::ExtractMapOp>::OpRewritePattern;
537   LogicalResult matchAndRewrite(vector::ExtractMapOp extract,
538                                 PatternRewriter &rewriter) const override {
539     Operation *definedOp = extract.getVector().getDefiningOp();
540     if (!definedOp || !OpTrait::hasElementwiseMappableTraits(definedOp) ||
541         definedOp->getNumResults() != 1)
542       return failure();
543     Location loc = extract.getLoc();
544     SmallVector<Value, 4> extractOperands;
545     for (OpOperand &operand : definedOp->getOpOperands()) {
546       auto vecType = operand.get().getType().template dyn_cast<VectorType>();
547       if (!vecType) {
548         extractOperands.push_back(operand.get());
549         continue;
550       }
551       extractOperands.push_back(rewriter.create<vector::ExtractMapOp>(
552           loc,
553           VectorType::get(extract.getResultType().getShape(),
554                           vecType.getElementType()),
555           operand.get(), extract.getIds()));
556     }
557     Operation *newOp = cloneOpWithOperandsAndTypes(
558         rewriter, loc, definedOp, extractOperands, extract.getResultType());
559     rewriter.replaceOp(extract, newOp->getResult(0));
560     return success();
561   }
562 };
563 
564 /// Canonicalize an extract_map using the result of a contract operation.
565 /// This propagate the extract_map to operands.
566 struct ContractExtractPattern : public OpRewritePattern<vector::ExtractMapOp> {
567   using OpRewritePattern<vector::ExtractMapOp>::OpRewritePattern;
568   LogicalResult matchAndRewrite(vector::ExtractMapOp extract,
569                                 PatternRewriter &rewriter) const override {
570     Operation *definedOp = extract.getVector().getDefiningOp();
571     auto contract = dyn_cast_or_null<vector::ContractionOp>(definedOp);
572     if (!contract)
573       return failure();
574     Location loc = contract.getLoc();
575     unsigned accIndex = vector::ContractionOp::getAccOperandIndex();
576     AffineMap affineMap = contract.getIndexingMaps()[accIndex];
577     // Create a map of the dimensions distributed based on the acc affine map.
578     // Only parallel dimensions are being distributed, reduction dimensions are
579     // untouched.
580     DenseMap<int64_t, int64_t> map;
581     for (unsigned i : llvm::seq(unsigned(0), affineMap.getNumResults()))
582       map[affineMap.getDimPosition(i)] = extract.getResultType().getDimSize(i);
583     SmallVector<Value, 4> extractOperands;
584     for (const auto &it : llvm::enumerate(contract.getIndexingMaps())) {
585       // For each operands calculate the new vector type after distribution.
586       Value operand = contract->getOperand(it.index());
587       auto vecType = operand.getType().cast<VectorType>();
588       SmallVector<int64_t> operandShape(vecType.getShape().begin(),
589                                         vecType.getShape().end());
590       for (unsigned i : llvm::seq(unsigned(0), it.value().getNumResults())) {
591         unsigned dim = it.value().getDimPosition(i);
592         auto distributedDim = map.find(dim);
593         // If the dimension is not in the map it means it is a reduction and
594         // doesn't get distributed.
595         if (distributedDim == map.end())
596           continue;
597         operandShape[i] = distributedDim->second;
598       }
599       VectorType newVecType =
600           VectorType::get(operandShape, vecType.getElementType());
601       extractOperands.push_back(rewriter.create<vector::ExtractMapOp>(
602           loc, newVecType, operand, extract.getIds()));
603     }
604     Operation *newOp =
605         cloneOpWithOperandsAndTypes(rewriter, loc, definedOp, extractOperands,
606                                     extract.getResult().getType());
607     rewriter.replaceOp(extract, newOp->getResult(0));
608     return success();
609   }
610 };
611 
612 /// Converts TransferRead op used by ExtractMap op into a smaller dimension
613 /// TransferRead.
614 /// Example:
615 /// ```
616 /// %a = vector.transfer_read %A[%c0, %c0, %c0], %cf0:
617 ///   memref<64x64x64xf32>, vector<64x4x32xf32>
618 /// %e = vector.extract_map %a[%id] : vector<64x4x32xf32> to vector<2x4x1xf32>
619 /// ```
620 /// to:
621 /// ```
622 /// %id1 = affine.apply affine_map<()[s0] -> (s0 * 2)> (%id)
623 /// %e = vector.transfer_read %A[%id1, %c0, %id1], %cf0 :
624 ///   memref<64x64x64xf32>, vector<2x4x1xf32>
625 /// ```
626 struct TransferReadExtractPattern
627     : public OpRewritePattern<vector::TransferReadOp> {
628   TransferReadExtractPattern(MLIRContext *context)
629       : OpRewritePattern<vector::TransferReadOp>(context) {}
630   LogicalResult matchAndRewrite(vector::TransferReadOp read,
631                                 PatternRewriter &rewriter) const override {
632     // TODO: support 0-d corner case.
633     if (read.getTransferRank() == 0)
634       return failure();
635 
636     if (!read.getResult().hasOneUse())
637       return failure();
638     auto extract =
639         dyn_cast<vector::ExtractMapOp>(*read.getResult().getUsers().begin());
640     if (!extract)
641       return failure();
642     if (read.getMask())
643       return failure();
644 
645     SmallVector<Value, 4> indices(read.getIndices().begin(),
646                                   read.getIndices().end());
647     AffineMap indexMap = extract.map().compose(read.getPermutationMap());
648     unsigned idCount = 0;
649     ImplicitLocOpBuilder lb(read.getLoc(), rewriter);
650     for (auto it :
651          llvm::zip(indexMap.getResults(), extract.map().getResults())) {
652       AffineExpr d0, d1;
653       bindDims(read.getContext(), d0, d1);
654       auto indexExpr = std::get<0>(it).dyn_cast<AffineDimExpr>();
655       if (!indexExpr)
656         continue;
657       unsigned indexPos = indexExpr.getPosition();
658       unsigned vectorPos = std::get<1>(it).cast<AffineDimExpr>().getPosition();
659       auto scale = getAffineConstantExpr(
660           extract.getResultType().getDimSize(vectorPos), read.getContext());
661       indices[indexPos] = makeComposedAffineApply(
662           rewriter, read.getLoc(), d0 + scale * d1,
663           {indices[indexPos], extract.getIds()[idCount++]});
664     }
665     Value newRead = lb.create<vector::TransferReadOp>(
666         extract.getType(), read.getSource(), indices,
667         read.getPermutationMapAttr(), read.getPadding(), read.getMask(),
668         read.getInBoundsAttr());
669     Value dest = lb.create<arith::ConstantOp>(
670         read.getType(), rewriter.getZeroAttr(read.getType()));
671     newRead = lb.create<vector::InsertMapOp>(newRead, dest, extract.getIds());
672     rewriter.replaceOp(read, newRead);
673     return success();
674   }
675 };
676 
677 struct TransferWriteInsertPattern
678     : public OpRewritePattern<vector::TransferWriteOp> {
679   TransferWriteInsertPattern(MLIRContext *context)
680       : OpRewritePattern<vector::TransferWriteOp>(context) {}
681   LogicalResult matchAndRewrite(vector::TransferWriteOp write,
682                                 PatternRewriter &rewriter) const override {
683     // TODO: support 0-d corner case.
684     if (write.getTransferRank() == 0)
685       return failure();
686 
687     auto insert = write.getVector().getDefiningOp<vector::InsertMapOp>();
688     if (!insert)
689       return failure();
690     if (write.getMask())
691       return failure();
692     SmallVector<Value, 4> indices(write.getIndices().begin(),
693                                   write.getIndices().end());
694     AffineMap indexMap = insert.map().compose(write.getPermutationMap());
695     unsigned idCount = 0;
696     Location loc = write.getLoc();
697     for (auto it :
698          llvm::zip(indexMap.getResults(), insert.map().getResults())) {
699       AffineExpr d0, d1;
700       bindDims(write.getContext(), d0, d1);
701       auto indexExpr = std::get<0>(it).dyn_cast<AffineDimExpr>();
702       if (!indexExpr)
703         continue;
704       unsigned indexPos = indexExpr.getPosition();
705       unsigned vectorPos = std::get<1>(it).cast<AffineDimExpr>().getPosition();
706       auto scale = getAffineConstantExpr(
707           insert.getSourceVectorType().getDimSize(vectorPos),
708           write.getContext());
709       indices[indexPos] = makeComposedAffineApply(
710           rewriter, loc, d0 + scale * d1,
711           {indices[indexPos], insert.getIds()[idCount++]});
712     }
713     rewriter.create<vector::TransferWriteOp>(
714         loc, insert.getVector(), write.getSource(), indices,
715         write.getPermutationMapAttr(), write.getInBoundsAttr());
716     rewriter.eraseOp(write);
717     return success();
718   }
719 };
720 
721 struct UnrollReductionPattern : public OpRewritePattern<vector::ReductionOp> {
722   UnrollReductionPattern(MLIRContext *context,
723                          const vector::UnrollVectorOptions &options)
724       : OpRewritePattern<vector::ReductionOp>(context, /*benefit=*/1),
725         options(options) {}
726 
727   LogicalResult matchAndRewrite(vector::ReductionOp reductionOp,
728                                 PatternRewriter &rewriter) const override {
729     Optional<SmallVector<int64_t, 4>> targetShape =
730         getTargetShape(options, reductionOp);
731     if (!targetShape)
732       return failure();
733     SmallVector<int64_t> originalSize = *reductionOp.getShapeForUnroll();
734     int64_t ratio = (*shapeRatio(originalSize, *targetShape))[0];
735 
736     // Create unrolled vector reduction.
737     Location loc = reductionOp.getLoc();
738     Value accumulator = nullptr;
739     for (int64_t i = 0; i < ratio; ++i) {
740       SmallVector<int64_t> offsets =
741           getVectorOffset(originalSize, *targetShape, i);
742       SmallVector<int64_t> strides(offsets.size(), 1);
743       Value slicedOperand = rewriter.create<vector::ExtractStridedSliceOp>(
744           loc, reductionOp.getVector(), offsets, *targetShape, strides);
745       Operation *newOp = cloneOpWithOperandsAndTypes(
746           rewriter, loc, reductionOp, slicedOperand, reductionOp.getType());
747       Value result = newOp->getResult(0);
748 
749       if (!accumulator) {
750         // This is the first reduction.
751         accumulator = result;
752       } else {
753         // On subsequent reduction, combine with the accumulator.
754         accumulator = makeArithReduction(rewriter, loc, reductionOp.getKind(),
755                                          accumulator, result);
756       }
757     }
758 
759     rewriter.replaceOp(reductionOp, accumulator);
760     return success();
761   }
762 
763 private:
764   const vector::UnrollVectorOptions options;
765 };
766 
767 struct UnrollTranposePattern : public OpRewritePattern<vector::TransposeOp> {
768   UnrollTranposePattern(MLIRContext *context,
769                         const vector::UnrollVectorOptions &options)
770       : OpRewritePattern<vector::TransposeOp>(context, /*benefit=*/1),
771         options(options) {}
772   LogicalResult matchAndRewrite(vector::TransposeOp tranposeOp,
773                                 PatternRewriter &rewriter) const override {
774     if (tranposeOp.getResultType().getRank() == 0)
775       return failure();
776     auto targetShape = getTargetShape(options, tranposeOp);
777     if (!targetShape)
778       return failure();
779     auto originalVectorType = tranposeOp.getResultType();
780     SmallVector<int64_t, 4> strides(targetShape->size(), 1);
781     Location loc = tranposeOp.getLoc();
782     ArrayRef<int64_t> originalSize = originalVectorType.getShape();
783     SmallVector<int64_t, 4> ratio = *shapeRatio(originalSize, *targetShape);
784     int64_t sliceCount = computeMaxLinearIndex(ratio);
785     // Prepare the result vector;
786     Value result = rewriter.create<arith::ConstantOp>(
787         loc, originalVectorType, rewriter.getZeroAttr(originalVectorType));
788     SmallVector<int64_t> permutation;
789     tranposeOp.getTransp(permutation);
790     for (int64_t i = 0; i < sliceCount; i++) {
791       SmallVector<int64_t, 4> elementOffsets =
792           getVectorOffset(originalSize, *targetShape, i);
793       SmallVector<int64_t, 4> permutedOffsets(elementOffsets.size());
794       SmallVector<int64_t, 4> permutedShape(elementOffsets.size());
795       // Compute the source offsets and shape.
796       for (auto &indices : llvm::enumerate(permutation)) {
797         permutedOffsets[indices.value()] = elementOffsets[indices.index()];
798         permutedShape[indices.value()] = (*targetShape)[indices.index()];
799       }
800       Value slicedOperand = rewriter.create<vector::ExtractStridedSliceOp>(
801           loc, tranposeOp.getVector(), permutedOffsets, permutedShape, strides);
802       Value tranposedSlice =
803           rewriter.create<vector::TransposeOp>(loc, slicedOperand, permutation);
804       result = rewriter.create<vector::InsertStridedSliceOp>(
805           loc, tranposedSlice, result, elementOffsets, strides);
806     }
807     rewriter.replaceOp(tranposeOp, result);
808     return success();
809   }
810 
811 private:
812   vector::UnrollVectorOptions options;
813 };
814 
815 } // namespace
816 
817 void mlir::vector::populateVectorUnrollPatterns(
818     RewritePatternSet &patterns, const UnrollVectorOptions &options) {
819   patterns.add<UnrollTransferReadPattern, UnrollTransferWritePattern,
820                UnrollContractionPattern, UnrollElementwisePattern,
821                UnrollReductionPattern, UnrollMultiReductionPattern,
822                UnrollTranposePattern>(patterns.getContext(), options);
823 }
824 
825 void mlir::vector::populatePropagateVectorDistributionPatterns(
826     RewritePatternSet &patterns) {
827   patterns.add<PointwiseExtractPattern, ContractExtractPattern,
828                TransferReadExtractPattern, TransferWriteInsertPattern>(
829       patterns.getContext());
830 }
831