1 //= TestAffineLoopParametricTiling.cpp -- Parametric Affine loop tiling pass =//
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 a test pass to test parametric tiling of perfectly
10 // nested affine for loops.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "mlir/Dialect/Affine/IR/AffineOps.h"
15 #include "mlir/Dialect/Affine/LoopUtils.h"
16 #include "mlir/Dialect/Affine/Passes.h"
17 #include "mlir/Dialect/Func/IR/FuncOps.h"
18
19 using namespace mlir;
20 using namespace mlir::affine;
21
22 #define DEBUG_TYPE "test-affine-parametric-tile"
23
24 namespace {
25 struct TestAffineLoopParametricTiling
26 : public PassWrapper<TestAffineLoopParametricTiling,
27 OperationPass<func::FuncOp>> {
MLIR_DEFINE_EXPLICIT_INTERNAL_INLINE_TYPE_ID__anon6f2407ba0111::TestAffineLoopParametricTiling28 MLIR_DEFINE_EXPLICIT_INTERNAL_INLINE_TYPE_ID(TestAffineLoopParametricTiling)
29
30 StringRef getArgument() const final { return "test-affine-parametric-tile"; }
getDescription__anon6f2407ba0111::TestAffineLoopParametricTiling31 StringRef getDescription() const final {
32 return "Tile affine loops using SSA values as tile sizes";
33 }
34 void runOnOperation() override;
35 };
36 } // namespace
37
38 /// Checks if the function enclosing the loop nest has any arguments passed to
39 /// it, which can be used as tiling parameters. Assumes that atleast 'n'
40 /// arguments are passed, where 'n' is the number of loops in the loop nest.
checkIfTilingParametersExist(ArrayRef<AffineForOp> band)41 static LogicalResult checkIfTilingParametersExist(ArrayRef<AffineForOp> band) {
42 assert(!band.empty() && "no loops in input band");
43 AffineForOp topLoop = band[0];
44
45 if (func::FuncOp funcOp = dyn_cast<func::FuncOp>(topLoop->getParentOp()))
46 if (funcOp.getNumArguments() < band.size())
47 return topLoop->emitError(
48 "too few tile sizes provided in the argument list of the function "
49 "which contains the current band");
50 return success();
51 }
52
53 /// Captures tiling parameters, which are expected to be passed as arguments
54 /// to the function enclosing the loop nest. Also checks if the required
55 /// parameters are of index type. This approach is temporary for testing
56 /// purposes.
57 static LogicalResult
getTilingParameters(ArrayRef<AffineForOp> band,SmallVectorImpl<Value> & tilingParameters)58 getTilingParameters(ArrayRef<AffineForOp> band,
59 SmallVectorImpl<Value> &tilingParameters) {
60 AffineForOp topLoop = band[0];
61 Region *funcOpRegion = topLoop->getParentRegion();
62 unsigned nestDepth = band.size();
63
64 for (BlockArgument blockArgument :
65 funcOpRegion->getArguments().take_front(nestDepth)) {
66 if (blockArgument.getArgNumber() < nestDepth) {
67 if (!blockArgument.getType().isIndex())
68 return topLoop->emitError(
69 "expected tiling parameters to be of index type");
70 tilingParameters.push_back(blockArgument);
71 }
72 }
73 return success();
74 }
75
runOnOperation()76 void TestAffineLoopParametricTiling::runOnOperation() {
77 // Bands of loops to tile.
78 std::vector<SmallVector<AffineForOp, 6>> bands;
79 getTileableBands(getOperation(), &bands);
80
81 // Tile each band.
82 for (MutableArrayRef<AffineForOp> band : bands) {
83 // Capture the tiling parameters from the arguments to the function
84 // enclosing this loop nest.
85 SmallVector<AffineForOp, 6> tiledNest;
86 SmallVector<Value, 6> tilingParameters;
87 // Check if tiling parameters are present.
88 if (checkIfTilingParametersExist(band).failed())
89 return;
90
91 // Get function arguments as tiling parameters.
92 if (getTilingParameters(band, tilingParameters).failed())
93 return;
94
95 (void)tilePerfectlyNestedParametric(band, tilingParameters, &tiledNest);
96 }
97 }
98
99 namespace mlir {
100 namespace test {
registerTestAffineLoopParametricTilingPass()101 void registerTestAffineLoopParametricTilingPass() {
102 PassRegistration<TestAffineLoopParametricTiling>();
103 }
104 } // namespace test
105 } // namespace mlir
106