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/Passes.h"
16 #include "mlir/Transforms/LoopUtils.h"
17
18 using namespace mlir;
19
20 #define DEBUG_TYPE "test-affine-parametric-tile"
21
22 namespace {
23 struct TestAffineLoopParametricTiling
24 : public PassWrapper<TestAffineLoopParametricTiling, FunctionPass> {
25 void runOnFunction() override;
26 };
27 } // end anonymous namespace
28
29 /// Checks if the function enclosing the loop nest has any arguments passed to
30 /// it, which can be used as tiling parameters. Assumes that atleast 'n'
31 /// arguments are passed, where 'n' is the number of loops in the loop nest.
checkIfTilingParametersExist(ArrayRef<AffineForOp> band)32 static void checkIfTilingParametersExist(ArrayRef<AffineForOp> band) {
33 assert(!band.empty() && "no loops in input band");
34 AffineForOp topLoop = band[0];
35
36 if (FuncOp funcOp = dyn_cast<FuncOp>(topLoop->getParentOp()))
37 assert(funcOp.getNumArguments() >= band.size() && "Too few tile sizes");
38 }
39
40 /// Captures tiling parameters, which are expected to be passed as arguments
41 /// to the function enclosing the loop nest. Also checks if the required
42 /// parameters are of index type. This approach is temporary for testing
43 /// purposes.
getTilingParameters(ArrayRef<AffineForOp> band,SmallVectorImpl<Value> & tilingParameters)44 static void getTilingParameters(ArrayRef<AffineForOp> band,
45 SmallVectorImpl<Value> &tilingParameters) {
46 AffineForOp topLoop = band[0];
47 Region *funcOpRegion = topLoop->getParentRegion();
48 unsigned nestDepth = band.size();
49
50 for (BlockArgument blockArgument :
51 funcOpRegion->getArguments().take_front(nestDepth)) {
52 if (blockArgument.getArgNumber() < nestDepth) {
53 assert(blockArgument.getType().isIndex() &&
54 "expected tiling parameters to be of index type.");
55 tilingParameters.push_back(blockArgument);
56 }
57 }
58 }
59
runOnFunction()60 void TestAffineLoopParametricTiling::runOnFunction() {
61 // Bands of loops to tile.
62 std::vector<SmallVector<AffineForOp, 6>> bands;
63 getTileableBands(getFunction(), &bands);
64
65 // Tile each band.
66 for (SmallVectorImpl<AffineForOp> &band : bands) {
67 // Capture the tiling parameters from the arguments to the function
68 // enclosing this loop nest.
69 SmallVector<AffineForOp, 6> tiledNest;
70 SmallVector<Value, 6> tilingParameters;
71 // Check if tiling parameters are present.
72 checkIfTilingParametersExist(band);
73
74 // Get function arguments as tiling parameters.
75 getTilingParameters(band, tilingParameters);
76
77 if (failed(
78 tilePerfectlyNestedParametric(band, tilingParameters, &tiledNest)))
79 return signalPassFailure();
80 }
81 }
82
83 namespace mlir {
84 namespace test {
registerTestAffineLoopParametricTilingPass()85 void registerTestAffineLoopParametricTilingPass() {
86 PassRegistration<TestAffineLoopParametricTiling>(
87 "test-affine-parametric-tile",
88 "Tile affine loops using SSA values as tile sizes");
89 }
90 } // namespace test
91 } // namespace mlir
92