1 //===- SCFToGPUPass.cpp - Convert a loop nest to a GPU kernel -----------===//
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/SCFToGPU/SCFToGPUPass.h"
10 #include "../PassDetail.h"
11 #include "mlir/Conversion/SCFToGPU/SCFToGPU.h"
12 #include "mlir/Dialect/Affine/IR/AffineOps.h"
13 #include "mlir/Dialect/Arithmetic/IR/Arithmetic.h"
14 #include "mlir/Dialect/Complex/IR/Complex.h"
15 #include "mlir/Dialect/GPU/GPUDialect.h"
16 #include "mlir/Dialect/SCF/SCF.h"
17 #include "mlir/Dialect/StandardOps/IR/Ops.h"
18 #include "mlir/Transforms/DialectConversion.h"
19 
20 #include "llvm/ADT/ArrayRef.h"
21 #include "llvm/Support/CommandLine.h"
22 
23 using namespace mlir;
24 using namespace mlir::scf;
25 
26 namespace {
27 // A pass that traverses top-level loops in the function and converts them to
28 // GPU launch operations.  Nested launches are not allowed, so this does not
29 // walk the function recursively to avoid considering nested loops.
30 struct ForLoopMapper : public ConvertAffineForToGPUBase<ForLoopMapper> {
31   ForLoopMapper() = default;
32   ForLoopMapper(unsigned numBlockDims, unsigned numThreadDims) {
33     this->numBlockDims = numBlockDims;
34     this->numThreadDims = numThreadDims;
35   }
36 
37   void runOnFunction() override {
38     for (Operation &op : llvm::make_early_inc_range(getFunction().getOps())) {
39       if (auto forOp = dyn_cast<AffineForOp>(&op)) {
40         if (failed(convertAffineLoopNestToGPULaunch(forOp, numBlockDims,
41                                                     numThreadDims)))
42           signalPassFailure();
43       }
44     }
45   }
46 };
47 
48 struct ParallelLoopToGpuPass
49     : public ConvertParallelLoopToGpuBase<ParallelLoopToGpuPass> {
50   void runOnOperation() override {
51     RewritePatternSet patterns(&getContext());
52     populateParallelLoopToGPUPatterns(patterns);
53     ConversionTarget target(getContext());
54     target.markUnknownOpDynamicallyLegal([](Operation *) { return true; });
55     configureParallelLoopToGPULegality(target);
56     if (failed(applyPartialConversion(getOperation(), target,
57                                       std::move(patterns))))
58       signalPassFailure();
59     finalizeParallelLoopToGPUConversion(getOperation());
60   }
61 };
62 
63 } // namespace
64 
65 std::unique_ptr<OperationPass<FuncOp>>
66 mlir::createAffineForToGPUPass(unsigned numBlockDims, unsigned numThreadDims) {
67   return std::make_unique<ForLoopMapper>(numBlockDims, numThreadDims);
68 }
69 std::unique_ptr<OperationPass<FuncOp>> mlir::createAffineForToGPUPass() {
70   return std::make_unique<ForLoopMapper>();
71 }
72 
73 std::unique_ptr<Pass> mlir::createParallelLoopToGpuPass() {
74   return std::make_unique<ParallelLoopToGpuPass>();
75 }
76