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| 1 | +//====- UnifyFuncReturn.cpp -------------------------------------*- C++ -*-===// |
| 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 "PassDetail.h" |
| 10 | +#include "mlir/IR/PatternMatch.h" |
| 11 | +#include "mlir/Support/LogicalResult.h" |
| 12 | +#include "mlir/Transforms/GreedyPatternRewriteDriver.h" |
| 13 | +#include "clang/CIR/Dialect/IR/CIRDialect.h" |
| 14 | +#include "clang/CIR/Dialect/Passes.h" |
| 15 | +#include "llvm/Support/TimeProfiler.h" |
| 16 | + |
| 17 | +using namespace mlir; |
| 18 | +using namespace cir; |
| 19 | + |
| 20 | +namespace { |
| 21 | + |
| 22 | +struct UnifyFuncReturnPass : public UnifyFuncReturnBase<UnifyFuncReturnPass> { |
| 23 | + UnifyFuncReturnPass() = default; |
| 24 | + void runOnOperation() override; |
| 25 | + |
| 26 | +private: |
| 27 | + void unifyReturn(FuncOp func); |
| 28 | +}; |
| 29 | + |
| 30 | +struct UnifyReturn : public OpRewritePattern<ReturnOp> { |
| 31 | + using OpRewritePattern<ReturnOp>::OpRewritePattern; |
| 32 | + |
| 33 | + UnifyReturn(MLIRContext *context, cir::FuncOp func, Block *retBlock) |
| 34 | + : OpRewritePattern<ReturnOp>(context), func(func), retBlock(retBlock) {} |
| 35 | + |
| 36 | + mlir::LogicalResult |
| 37 | + matchAndRewrite(cir::ReturnOp ret, |
| 38 | + mlir::PatternRewriter &rewriter) const override { |
| 39 | + mlir::OpBuilder::InsertionGuard guard(rewriter); |
| 40 | + auto fn = ret->getParentOfType<cir::FuncOp>(); |
| 41 | + if (!fn || fn != func) |
| 42 | + return mlir::failure(); |
| 43 | + // Replace 'return' with 'br <retBlock>' |
| 44 | + rewriter.replaceOpWithNewOp<cir::BrOp>(ret, ret.getInput(), retBlock); |
| 45 | + return mlir::success(); |
| 46 | + } |
| 47 | + |
| 48 | +private: |
| 49 | + cir::FuncOp func; |
| 50 | + Block *retBlock; |
| 51 | +}; |
| 52 | + |
| 53 | +} // namespace |
| 54 | + |
| 55 | +void UnifyFuncReturnPass::unifyReturn(cir::FuncOp func) { |
| 56 | + if (func.getRegion().empty()) |
| 57 | + return; |
| 58 | + |
| 59 | + bool hasRetVals = func.getNumResults() > 0; |
| 60 | + auto *endBody = &func.getBody().back(); |
| 61 | + auto *retBlock = endBody->splitBlock(endBody->end()); |
| 62 | + if (hasRetVals) |
| 63 | + retBlock->addArguments(func.getResultTypes(), func.getLoc()); |
| 64 | + |
| 65 | + RewritePatternSet patterns(&getContext()); |
| 66 | + patterns.add<UnifyReturn>(patterns.getContext(), func, retBlock); |
| 67 | + |
| 68 | + // Collect operations to apply patterns. |
| 69 | + llvm::SmallVector<Operation *, 16> ops; |
| 70 | + func->walk([&](cir::ReturnOp op) { ops.push_back(op.getOperation()); }); |
| 71 | + |
| 72 | + // Apply patterns. |
| 73 | + if (applyOpPatternsGreedily(ops, std::move(patterns)).failed()) |
| 74 | + signalPassFailure(); |
| 75 | + |
| 76 | + auto builder = OpBuilder::atBlockBegin(retBlock); |
| 77 | + if (hasRetVals) |
| 78 | + builder.create<cir::ReturnOp>(func.getLoc(), retBlock->getArguments()); |
| 79 | + else |
| 80 | + builder.create<cir::ReturnOp>(func.getLoc()); |
| 81 | +} |
| 82 | + |
| 83 | +void UnifyFuncReturnPass::runOnOperation() { |
| 84 | + llvm::TimeTraceScope scope("Unify function returns"); |
| 85 | + |
| 86 | + // Collect operations to apply patterns. |
| 87 | + llvm::SmallVector<Operation *, 16> ops; |
| 88 | + getOperation()->walk([&](cir::FuncOp op) { unifyReturn(op); }); |
| 89 | +} |
| 90 | + |
| 91 | +namespace mlir { |
| 92 | +std::unique_ptr<Pass> createUnifyFuncReturnPass() { |
| 93 | + return std::make_unique<UnifyFuncReturnPass>(); |
| 94 | +} |
| 95 | +} // namespace mlir |
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