1 //===-------- TestLoopUnrolling.cpp --- loop unrolling test 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 pass to unroll loops by a specified unroll factor.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "mlir/Dialect/Arithmetic/IR/Arithmetic.h"
14 #include "mlir/Dialect/SCF/SCF.h"
15 #include "mlir/Dialect/SCF/Utils/Utils.h"
16 #include "mlir/IR/Builders.h"
17 #include "mlir/Pass/Pass.h"
18 
19 using namespace mlir;
20 
21 namespace {
22 
23 static unsigned getNestingDepth(Operation *op) {
24   Operation *currOp = op;
25   unsigned depth = 0;
26   while ((currOp = currOp->getParentOp())) {
27     if (isa<scf::ForOp>(currOp))
28       depth++;
29   }
30   return depth;
31 }
32 
33 struct TestLoopUnrollingPass
34     : public PassWrapper<TestLoopUnrollingPass, OperationPass<>> {
35   MLIR_DEFINE_EXPLICIT_INTERNAL_INLINE_TYPE_ID(TestLoopUnrollingPass)
36 
37   StringRef getArgument() const final { return "test-loop-unrolling"; }
38   StringRef getDescription() const final {
39     return "Tests loop unrolling transformation";
40   }
41   TestLoopUnrollingPass() = default;
42   TestLoopUnrollingPass(const TestLoopUnrollingPass &) {}
43   explicit TestLoopUnrollingPass(uint64_t unrollFactorParam,
44                                  unsigned loopDepthParam,
45                                  bool annotateLoopParam) {
46     unrollFactor = unrollFactorParam;
47     loopDepth = loopDepthParam;
48     annotateLoop = annotateLoopParam;
49   }
50 
51   void getDependentDialects(DialectRegistry &registry) const override {
52     registry.insert<arith::ArithmeticDialect>();
53   }
54 
55   void runOnOperation() override {
56     SmallVector<scf::ForOp, 4> loops;
57     getOperation()->walk([&](scf::ForOp forOp) {
58       if (getNestingDepth(forOp) == loopDepth)
59         loops.push_back(forOp);
60     });
61     auto annotateFn = [this](unsigned i, Operation *op, OpBuilder b) {
62       if (annotateLoop) {
63         op->setAttr("unrolled_iteration", b.getUI32IntegerAttr(i));
64       }
65     };
66     for (auto loop : loops)
67       (void)loopUnrollByFactor(loop, unrollFactor, annotateFn);
68   }
69   Option<uint64_t> unrollFactor{*this, "unroll-factor",
70                                 llvm::cl::desc("Loop unroll factor."),
71                                 llvm::cl::init(1)};
72   Option<bool> annotateLoop{*this, "annotate",
73                             llvm::cl::desc("Annotate unrolled iterations."),
74                             llvm::cl::init(false)};
75   Option<bool> unrollUpToFactor{*this, "unroll-up-to-factor",
76                                 llvm::cl::desc("Loop unroll up to factor."),
77                                 llvm::cl::init(false)};
78   Option<unsigned> loopDepth{*this, "loop-depth", llvm::cl::desc("Loop depth."),
79                              llvm::cl::init(0)};
80 };
81 } // namespace
82 
83 namespace mlir {
84 namespace test {
85 void registerTestLoopUnrollingPass() {
86   PassRegistration<TestLoopUnrollingPass>();
87 }
88 } // namespace test
89 } // namespace mlir
90