xref: /llvm-project/mlir/lib/Dialect/Vector/Transforms/LowerVectorInterleave.cpp (revision 5df01ed79c47b0b10ea6be87251ec6e0484515a5)
1 //===- LowerVectorInterleave.cpp - Lower 'vector.interleave' operation ----===//
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 target-independent rewrites and utilities to lower the
10 // 'vector.interleave' operation.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "mlir/Dialect/Vector/IR/VectorOps.h"
15 #include "mlir/Dialect/Vector/Transforms/LoweringPatterns.h"
16 #include "mlir/Dialect/Vector/Utils/VectorUtils.h"
17 #include "mlir/IR/BuiltinTypes.h"
18 #include "mlir/IR/PatternMatch.h"
19 
20 #define DEBUG_TYPE "vector-interleave-lowering"
21 
22 using namespace mlir;
23 using namespace mlir::vector;
24 
25 namespace {
26 
27 /// A one-shot unrolling of vector.interleave to the `targetRank`.
28 ///
29 /// Example:
30 ///
31 /// ```mlir
32 /// vector.interleave %a, %b : vector<1x2x3x4xi64>
33 /// ```
34 /// Would be unrolled to:
35 /// ```mlir
36 /// %result = arith.constant dense<0> : vector<1x2x3x8xi64>
37 /// %0 = vector.extract %a[0, 0, 0]                 ─┐
38 ///        : vector<4xi64> from vector<1x2x3x4xi64>  |
39 /// %1 = vector.extract %b[0, 0, 0]                  |
40 ///        : vector<4xi64> from vector<1x2x3x4xi64>  | - Repeated 6x for
41 /// %2 = vector.interleave %0, %1 : vector<4xi64>    |   all leading positions
42 /// %3 = vector.insert %2, %result [0, 0, 0]         |
43 ///        : vector<8xi64> into vector<1x2x3x8xi64>  ┘
44 /// ```
45 ///
46 /// Note: If any leading dimension before the `targetRank` is scalable the
47 /// unrolling will stop before the scalable dimension.
48 class UnrollInterleaveOp : public OpRewritePattern<vector::InterleaveOp> {
49 public:
50   UnrollInterleaveOp(int64_t targetRank, MLIRContext *context,
51                      PatternBenefit benefit = 1)
52       : OpRewritePattern(context, benefit), targetRank(targetRank){};
53 
54   LogicalResult matchAndRewrite(vector::InterleaveOp op,
55                                 PatternRewriter &rewriter) const override {
56     VectorType resultType = op.getResultVectorType();
57     auto unrollIterator = vector::createUnrollIterator(resultType, targetRank);
58     if (!unrollIterator)
59       return failure();
60 
61     auto loc = op.getLoc();
62     Value result = rewriter.create<arith::ConstantOp>(
63         loc, resultType, rewriter.getZeroAttr(resultType));
64     for (auto position : *unrollIterator) {
65       Value extractLhs = rewriter.create<ExtractOp>(loc, op.getLhs(), position);
66       Value extractRhs = rewriter.create<ExtractOp>(loc, op.getRhs(), position);
67       Value interleave =
68           rewriter.create<InterleaveOp>(loc, extractLhs, extractRhs);
69       result = rewriter.create<InsertOp>(loc, interleave, result, position);
70     }
71 
72     rewriter.replaceOp(op, result);
73     return success();
74   }
75 
76 private:
77   int64_t targetRank = 1;
78 };
79 
80 } // namespace
81 
82 void mlir::vector::populateVectorInterleaveLoweringPatterns(
83     RewritePatternSet &patterns, int64_t targetRank, PatternBenefit benefit) {
84   patterns.add<UnrollInterleaveOp>(targetRank, patterns.getContext(), benefit);
85 }
86