1 //===- TestAffineDataCopy.cpp - Test affine data copy utility -------------===//
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 pass to test affine data copy utility functions and
10 // options.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "mlir/Dialect/Affine/Analysis/Utils.h"
15 #include "mlir/Dialect/Affine/IR/AffineOps.h"
16 #include "mlir/Dialect/MemRef/IR/MemRef.h"
17 #include "mlir/Pass/Pass.h"
18 #include "mlir/Transforms/GreedyPatternRewriteDriver.h"
19 #include "mlir/Transforms/LoopUtils.h"
20 #include "mlir/Transforms/Passes.h"
21 
22 #define PASS_NAME "test-affine-data-copy"
23 
24 using namespace mlir;
25 
26 static llvm::cl::OptionCategory clOptionsCategory(PASS_NAME " options");
27 
28 namespace {
29 
30 struct TestAffineDataCopy
31     : public PassWrapper<TestAffineDataCopy, OperationPass<FuncOp>> {
32   StringRef getArgument() const final { return PASS_NAME; }
33   StringRef getDescription() const final {
34     return "Tests affine data copy utility functions.";
35   }
36   TestAffineDataCopy() = default;
37   TestAffineDataCopy(const TestAffineDataCopy &pass) : PassWrapper(pass){};
38 
39   void getDependentDialects(DialectRegistry &registry) const override {
40     registry.insert<memref::MemRefDialect>();
41   }
42   void runOnOperation() override;
43 
44 private:
45   Option<bool> clMemRefFilter{
46       *this, "memref-filter",
47       llvm::cl::desc(
48           "Enable memref filter testing in affine data copy optimization"),
49       llvm::cl::init(false)};
50   Option<bool> clTestGenerateCopyForMemRegion{
51       *this, "for-memref-region",
52       llvm::cl::desc("Test copy generation for a single memref region"),
53       llvm::cl::init(false)};
54 };
55 
56 } // namespace
57 
58 void TestAffineDataCopy::runOnOperation() {
59   // Gather all AffineForOps by loop depth.
60   std::vector<SmallVector<AffineForOp, 2>> depthToLoops;
61   gatherLoops(getOperation(), depthToLoops);
62   assert(!depthToLoops.empty() && "Loop nest not found");
63 
64   // Only support tests with a single loop nest and a single innermost loop
65   // for now.
66   unsigned innermostLoopIdx = depthToLoops.size() - 1;
67   if (depthToLoops[0].size() != 1 || depthToLoops[innermostLoopIdx].size() != 1)
68     return;
69 
70   auto loopNest = depthToLoops[0][0];
71   auto innermostLoop = depthToLoops[innermostLoopIdx][0];
72   AffineLoadOp load;
73   if (clMemRefFilter || clTestGenerateCopyForMemRegion) {
74     // Gather MemRef filter. For simplicity, we use the first loaded memref
75     // found in the innermost loop.
76     for (auto &op : *innermostLoop.getBody()) {
77       if (auto ld = dyn_cast<AffineLoadOp>(op)) {
78         load = ld;
79         break;
80       }
81     }
82   }
83   if (!load)
84     return;
85 
86   AffineCopyOptions copyOptions = {/*generateDma=*/false,
87                                    /*slowMemorySpace=*/0,
88                                    /*fastMemorySpace=*/0,
89                                    /*tagMemorySpace=*/0,
90                                    /*fastMemCapacityBytes=*/32 * 1024 * 1024UL};
91   DenseSet<Operation *> copyNests;
92   if (clMemRefFilter) {
93     if (failed(affineDataCopyGenerate(loopNest, copyOptions, load.getMemRef(),
94                                       copyNests)))
95       return;
96   } else if (clTestGenerateCopyForMemRegion) {
97     CopyGenerateResult result;
98     MemRefRegion region(loopNest.getLoc());
99     if (failed(region.compute(load, /*loopDepth=*/0)))
100       return;
101     if (failed(generateCopyForMemRegion(region, loopNest, copyOptions, result)))
102       return;
103   }
104 
105   // Promote any single iteration loops in the copy nests and simplify
106   // load/stores.
107   SmallVector<Operation *, 4> copyOps;
108   for (Operation *nest : copyNests) {
109     // With a post order walk, the erasure of loops does not affect
110     // continuation of the walk or the collection of load/store ops.
111     nest->walk([&](Operation *op) {
112       if (auto forOp = dyn_cast<AffineForOp>(op))
113         (void)promoteIfSingleIteration(forOp);
114       else if (auto loadOp = dyn_cast<AffineLoadOp>(op))
115         copyOps.push_back(loadOp);
116       else if (auto storeOp = dyn_cast<AffineStoreOp>(op))
117         copyOps.push_back(storeOp);
118     });
119   }
120 
121   // Promoting single iteration loops could lead to simplification of
122   // generated load's/store's, and the latter could anyway also be
123   // canonicalized.
124   RewritePatternSet patterns(&getContext());
125   for (Operation *op : copyOps) {
126     patterns.clear();
127     if (isa<AffineLoadOp>(op)) {
128       AffineLoadOp::getCanonicalizationPatterns(patterns, &getContext());
129     } else {
130       assert(isa<AffineStoreOp>(op) && "expected affine store op");
131       AffineStoreOp::getCanonicalizationPatterns(patterns, &getContext());
132     }
133   }
134   (void)applyOpPatternsAndFold(copyOps, std::move(patterns), /*strict=*/true);
135 }
136 
137 namespace mlir {
138 void registerTestAffineDataCopyPass() {
139   PassRegistration<TestAffineDataCopy>();
140 }
141 } // namespace mlir
142