1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
|
//===- LowerVectorShapeCast.cpp - Lower 'vector.shape_cast' operation -----===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements target-independent rewrites and utilities to lower the
// 'vector.shape_cast' operation.
//
//===----------------------------------------------------------------------===//
#include "mlir/Dialect/Affine/IR/AffineOps.h"
#include "mlir/Dialect/Arith/IR/Arith.h"
#include "mlir/Dialect/Arith/Utils/Utils.h"
#include "mlir/Dialect/Linalg/IR/Linalg.h"
#include "mlir/Dialect/MemRef/IR/MemRef.h"
#include "mlir/Dialect/SCF/IR/SCF.h"
#include "mlir/Dialect/Tensor/IR/Tensor.h"
#include "mlir/Dialect/Utils/IndexingUtils.h"
#include "mlir/Dialect/Utils/StructuredOpsUtils.h"
#include "mlir/Dialect/Vector/IR/VectorOps.h"
#include "mlir/Dialect/Vector/Transforms/LoweringPatterns.h"
#include "mlir/Dialect/Vector/Transforms/VectorRewritePatterns.h"
#include "mlir/Dialect/Vector/Utils/VectorUtils.h"
#include "mlir/IR/BuiltinAttributeInterfaces.h"
#include "mlir/IR/BuiltinTypes.h"
#include "mlir/IR/ImplicitLocOpBuilder.h"
#include "mlir/IR/Location.h"
#include "mlir/IR/Matchers.h"
#include "mlir/IR/PatternMatch.h"
#include "mlir/IR/TypeUtilities.h"
#include "mlir/Interfaces/VectorInterfaces.h"
#include "mlir/Support/LogicalResult.h"
#define DEBUG_TYPE "vector-shape-cast-lowering"
using namespace mlir;
using namespace mlir::vector;
namespace {
/// ShapeOp 2D -> 1D downcast serves the purpose of flattening 2-D to 1-D
/// vectors progressively on the way to target llvm.matrix intrinsics.
/// This iterates over the most major dimension of the 2-D vector and performs
/// rewrites into:
/// vector.extract from 2-D + vector.insert_strided_slice offset into 1-D
class ShapeCastOp2DDownCastRewritePattern
: public OpRewritePattern<vector::ShapeCastOp> {
public:
using OpRewritePattern::OpRewritePattern;
LogicalResult matchAndRewrite(vector::ShapeCastOp op,
PatternRewriter &rewriter) const override {
auto sourceVectorType = op.getSourceVectorType();
auto resultVectorType = op.getResultVectorType();
if (sourceVectorType.getRank() != 2 || resultVectorType.getRank() != 1)
return failure();
auto loc = op.getLoc();
Value desc = rewriter.create<arith::ConstantOp>(
loc, resultVectorType, rewriter.getZeroAttr(resultVectorType));
unsigned mostMinorVectorSize = sourceVectorType.getShape()[1];
for (int64_t i = 0, e = sourceVectorType.getShape().front(); i != e; ++i) {
Value vec = rewriter.create<vector::ExtractOp>(loc, op.getSource(), i);
desc = rewriter.create<vector::InsertStridedSliceOp>(
loc, vec, desc,
/*offsets=*/i * mostMinorVectorSize, /*strides=*/1);
}
rewriter.replaceOp(op, desc);
return success();
}
};
/// ShapeOp 1D -> 2D upcast serves the purpose of unflattening 2-D from 1-D
/// vectors progressively.
/// This iterates over the most major dimension of the 2-D vector and performs
/// rewrites into:
/// vector.extract_strided_slice from 1-D + vector.insert into 2-D
/// Note that 1-D extract_strided_slice are lowered to efficient vector.shuffle.
class ShapeCastOp2DUpCastRewritePattern
: public OpRewritePattern<vector::ShapeCastOp> {
public:
using OpRewritePattern::OpRewritePattern;
LogicalResult matchAndRewrite(vector::ShapeCastOp op,
PatternRewriter &rewriter) const override {
auto sourceVectorType = op.getSourceVectorType();
auto resultVectorType = op.getResultVectorType();
if (sourceVectorType.getRank() != 1 || resultVectorType.getRank() != 2)
return failure();
auto loc = op.getLoc();
Value desc = rewriter.create<arith::ConstantOp>(
loc, resultVectorType, rewriter.getZeroAttr(resultVectorType));
unsigned mostMinorVectorSize = resultVectorType.getShape()[1];
for (int64_t i = 0, e = resultVectorType.getShape().front(); i != e; ++i) {
Value vec = rewriter.create<vector::ExtractStridedSliceOp>(
loc, op.getSource(), /*offsets=*/i * mostMinorVectorSize,
/*sizes=*/mostMinorVectorSize,
/*strides=*/1);
desc = rewriter.create<vector::InsertOp>(loc, vec, desc, i);
}
rewriter.replaceOp(op, desc);
return success();
}
};
// We typically should not lower general shape cast operations into data
// movement instructions, since the assumption is that these casts are
// optimized away during progressive lowering. For completeness, however,
// we fall back to a reference implementation that moves all elements
// into the right place if we get here.
class ShapeCastOpRewritePattern : public OpRewritePattern<vector::ShapeCastOp> {
public:
using OpRewritePattern::OpRewritePattern;
LogicalResult matchAndRewrite(vector::ShapeCastOp op,
PatternRewriter &rewriter) const override {
Location loc = op.getLoc();
auto sourceVectorType = op.getSourceVectorType();
auto resultVectorType = op.getResultVectorType();
// Special case 2D / 1D lowerings with better implementations.
// TODO: make is ND / 1D to allow generic ND -> 1D -> MD.
int64_t srcRank = sourceVectorType.getRank();
int64_t resRank = resultVectorType.getRank();
if ((srcRank == 2 && resRank == 1) || (srcRank == 1 && resRank == 2))
return failure();
// Generic ShapeCast lowering path goes all the way down to unrolled scalar
// extract/insert chains.
// TODO: consider evolving the semantics to only allow 1D source or dest and
// drop this potentially very expensive lowering.
// Compute number of elements involved in the reshape.
int64_t numElts = 1;
for (int64_t r = 0; r < srcRank; r++)
numElts *= sourceVectorType.getDimSize(r);
// Replace with data movement operations:
// x[0,0,0] = y[0,0]
// x[0,0,1] = y[0,1]
// x[0,1,0] = y[0,2]
// etc., incrementing the two index vectors "row-major"
// within the source and result shape.
SmallVector<int64_t> srcIdx(srcRank);
SmallVector<int64_t> resIdx(resRank);
Value result = rewriter.create<arith::ConstantOp>(
loc, resultVectorType, rewriter.getZeroAttr(resultVectorType));
for (int64_t i = 0; i < numElts; i++) {
if (i != 0) {
incIdx(srcIdx, sourceVectorType, srcRank - 1);
incIdx(resIdx, resultVectorType, resRank - 1);
}
Value extract;
if (srcRank == 0) {
// 0-D vector special case
assert(srcIdx.empty() && "Unexpected indices for 0-D vector");
extract = rewriter.create<vector::ExtractElementOp>(
loc, op.getSourceVectorType().getElementType(), op.getSource());
} else {
extract =
rewriter.create<vector::ExtractOp>(loc, op.getSource(), srcIdx);
}
if (resRank == 0) {
// 0-D vector special case
assert(resIdx.empty() && "Unexpected indices for 0-D vector");
result = rewriter.create<vector::InsertElementOp>(loc, extract, result);
} else {
result =
rewriter.create<vector::InsertOp>(loc, extract, result, resIdx);
}
}
rewriter.replaceOp(op, result);
return success();
}
private:
static void incIdx(SmallVector<int64_t> &idx, VectorType tp, int64_t r) {
assert(0 <= r && r < tp.getRank());
if (++idx[r] == tp.getDimSize(r)) {
idx[r] = 0;
incIdx(idx, tp, r - 1);
}
}
};
} // namespace
void mlir::vector::populateVectorShapeCastLoweringPatterns(
RewritePatternSet &patterns, PatternBenefit benefit) {
patterns.add<ShapeCastOp2DDownCastRewritePattern,
ShapeCastOp2DUpCastRewritePattern, ShapeCastOpRewritePattern>(
patterns.getContext(), benefit);
}
|
