1 /* Copyright 2021 The TensorFlow Authors. All Rights Reserved. 2 3 Licensed under the Apache License, Version 2.0 (the "License"); 4 you may not use this file except in compliance with the License. 5 You may obtain a copy of the License at 6 7 http://www.apache.org/licenses/LICENSE-2.0 8 9 Unless required by applicable law or agreed to in writing, software 10 distributed under the License is distributed on an "AS IS" BASIS, 11 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 See the License for the specific language governing permissions and 13 limitations under the License. 14 ==============================================================================*/ 15 16 #include <vector> 17 18 #include "llvm/ADT/ArrayRef.h" 19 #include "llvm/ADT/SmallPtrSet.h" 20 #include "mlir/Analysis/BufferViewFlowAnalysis.h" // from @llvm-project 21 #include "mlir/Dialect/Affine/IR/AffineOps.h" // from @llvm-project 22 #include "mlir/Dialect/Linalg/IR/LinalgOps.h" // from @llvm-project 23 #include "mlir/Dialect/Linalg/Transforms/CodegenStrategy.h" // from @llvm-project 24 #include "mlir/Dialect/Linalg/Transforms/Transforms.h" // from @llvm-project 25 #include "mlir/Dialect/MemRef/IR/MemRef.h" // from @llvm-project 26 #include "mlir/Dialect/SCF/SCF.h" // from @llvm-project 27 #include "mlir/Dialect/Shape/IR/Shape.h" // from @llvm-project 28 #include "mlir/Dialect/StandardOps/IR/Ops.h" // from @llvm-project 29 #include "mlir/IR/AffineMap.h" // from @llvm-project 30 #include "mlir/IR/BuiltinTypes.h" // from @llvm-project 31 #include "mlir/IR/ImplicitLocOpBuilder.h" // from @llvm-project 32 #include "mlir/Transforms/GreedyPatternRewriteDriver.h" // from @llvm-project 33 #include "tensorflow/compiler/mlir/hlo/include/mlir-hlo/Dialect/mhlo/IR/lhlo_ops.h" 34 #include "tensorflow/compiler/mlir/tools/kernel_gen/ir/tf_framework_ops.h" 35 #include "tensorflow/compiler/mlir/tools/kernel_gen/transforms/passes.h" 36 #include "tensorflow/compiler/mlir/tools/kernel_gen/transforms/rewriters.h" 37 38 namespace mlir { 39 namespace kernel_gen { 40 namespace transforms { 41 namespace { 42 #define GEN_PASS_CLASSES 43 #include "tensorflow/compiler/mlir/tools/kernel_gen/transforms/kernel_gen_passes.h.inc" 44 45 // A pass to remove memref::AllocOps and memref::CopyOps ops if the only user 46 // of the copy is a linalg::GenericOp. RemoveMemrefCopy(FuncOp func)47void RemoveMemrefCopy(FuncOp func) { 48 llvm::SmallVector<memref::AllocOp, 8> allocs_to_remove; 49 llvm::SmallVector<memref::CopyOp, 8> copies_to_remove; 50 51 // Gather all allocs and copies which are consumed by linalg::GenericOp ops. 52 func->walk([&](memref::AllocOp op) { 53 memref::CopyOp copy; 54 linalg::GenericOp generic; 55 bool at_most_one_copy = true; 56 bool at_most_one_generic = true; 57 for (auto user : op->getUsers()) { 58 if (auto copy_user = dyn_cast<memref::CopyOp>(user)) { 59 if (copy) { 60 at_most_one_copy = false; 61 } else { 62 copy = copy_user; 63 } 64 } else if (auto generic_user = dyn_cast<linalg::GenericOp>(user)) { 65 if (generic) { 66 at_most_one_generic = false; 67 } else { 68 generic = generic_user; 69 } 70 } 71 } 72 if (!copy || !at_most_one_copy) return; 73 if (!generic || !at_most_one_generic) return; 74 // The copy should have the alloc op as target. 75 if (copy.getTarget() != op.getResult()) return; 76 77 // The copy should be before the linalg::GenericOp. 78 if (copy->getBlock() != generic->getBlock() || 79 !copy->isBeforeInBlock(generic)) { 80 return; 81 } 82 allocs_to_remove.push_back(op); 83 copies_to_remove.push_back(copy); 84 }); 85 for (auto it : llvm::zip(allocs_to_remove, copies_to_remove)) { 86 auto alloc_op = std::get<0>(it); 87 auto copy_op = std::get<1>(it); 88 auto source = copy_op.getSource().getDefiningOp(); 89 copy_op->erase(); 90 alloc_op->replaceAllUsesWith(source); 91 alloc_op->erase(); 92 } 93 } 94 } // namespace 95 96 struct CopyCleanupPass : public CopyCleanupPassBase<CopyCleanupPass> { getDependentDialectsmlir::kernel_gen::transforms::CopyCleanupPass97 void getDependentDialects(DialectRegistry ®istry) const override { 98 registry.insert<memref::MemRefDialect, linalg::LinalgDialect>(); 99 } 100 runOnFunctionmlir::kernel_gen::transforms::CopyCleanupPass101 void runOnFunction() override { RemoveMemrefCopy(getFunction()); } 102 }; 103 CreateCopyCleanupPass()104std::unique_ptr<FunctionPass> CreateCopyCleanupPass() { 105 return std::make_unique<CopyCleanupPass>(); 106 } 107 108 } // namespace transforms 109 } // namespace kernel_gen 110 } // namespace mlir 111