1 //===- OpenMPToLLVM.cpp - conversion from OpenMP to LLVM dialect ----------===//
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 #include "mlir/Conversion/OpenMPToLLVM/ConvertOpenMPToLLVM.h"
10 
11 #include "../PassDetail.h"
12 #include "mlir/Conversion/StandardToLLVM/ConvertStandardToLLVM.h"
13 #include "mlir/Dialect/LLVMIR/LLVMDialect.h"
14 #include "mlir/Dialect/OpenMP/OpenMPDialect.h"
15 
16 using namespace mlir;
17 
18 namespace {
19 /// A pattern that converts the region arguments in a single-region OpenMP
20 /// operation to the LLVM dialect. The body of the region is not modified and is
21 /// expected to either be processed by the conversion infrastructure or already
22 /// contain ops compatible with LLVM dialect types.
23 template <typename OpType>
24 struct RegionOpConversion : public ConvertOpToLLVMPattern<OpType> {
25   using ConvertOpToLLVMPattern<OpType>::ConvertOpToLLVMPattern;
26 
27   LogicalResult
28   matchAndRewrite(OpType curOp, ArrayRef<Value> operands,
29                   ConversionPatternRewriter &rewriter) const override {
30     auto newOp = rewriter.create<OpType>(curOp.getLoc(), TypeRange(), operands,
31                                          curOp->getAttrs());
32     rewriter.inlineRegionBefore(curOp.region(), newOp.region(),
33                                 newOp.region().end());
34     if (failed(rewriter.convertRegionTypes(&newOp.region(),
35                                            *this->getTypeConverter())))
36       return failure();
37 
38     rewriter.eraseOp(curOp);
39     return success();
40   }
41 };
42 } // namespace
43 
44 void mlir::populateOpenMPToLLVMConversionPatterns(LLVMTypeConverter &converter,
45                                                   RewritePatternSet &patterns) {
46   patterns.add<RegionOpConversion<omp::ParallelOp>,
47                RegionOpConversion<omp::WsLoopOp>>(converter);
48 }
49 
50 namespace {
51 struct ConvertOpenMPToLLVMPass
52     : public ConvertOpenMPToLLVMBase<ConvertOpenMPToLLVMPass> {
53   void runOnOperation() override;
54 };
55 } // namespace
56 
57 void ConvertOpenMPToLLVMPass::runOnOperation() {
58   auto module = getOperation();
59 
60   // Convert to OpenMP operations with LLVM IR dialect
61   RewritePatternSet patterns(&getContext());
62   LLVMTypeConverter converter(&getContext());
63   populateStdToLLVMConversionPatterns(converter, patterns);
64   populateOpenMPToLLVMConversionPatterns(converter, patterns);
65 
66   LLVMConversionTarget target(getContext());
67   target.addDynamicallyLegalOp<omp::ParallelOp, omp::WsLoopOp>(
68       [&](Operation *op) { return converter.isLegal(&op->getRegion(0)); });
69   target.addLegalOp<omp::TerminatorOp, omp::TaskyieldOp, omp::FlushOp,
70                     omp::BarrierOp, omp::TaskwaitOp>();
71   if (failed(applyPartialConversion(module, target, std::move(patterns))))
72     signalPassFailure();
73 }
74 
75 std::unique_ptr<OperationPass<ModuleOp>> mlir::createConvertOpenMPToLLVMPass() {
76   return std::make_unique<ConvertOpenMPToLLVMPass>();
77 }
78