1 //===-- UnreachableBlockElim.h - Remove unreachable blocks for codegen --===// 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 pass is an extremely simple version of the SimplifyCFG pass. Its sole 10 // job is to delete LLVM basic blocks that are not reachable from the entry 11 // node. To do this, it performs a simple depth first traversal of the CFG, 12 // then deletes any unvisited nodes. 13 // 14 // Note that this pass is really a hack. In particular, the instruction 15 // selectors for various targets should just not generate code for unreachable 16 // blocks. Until LLVM has a more systematic way of defining instruction 17 // selectors, however, we cannot really expect them to handle additional 18 // complexity. 19 // 20 //===----------------------------------------------------------------------===// 21 22 #ifndef LLVM_CODEGEN_UNREACHABLEBLOCKELIM_H 23 #define LLVM_CODEGEN_UNREACHABLEBLOCKELIM_H 24 25 #include "llvm/IR/PassManager.h" 26 27 namespace llvm { 28 29 class UnreachableBlockElimPass 30 : public PassInfoMixin<UnreachableBlockElimPass> { 31 public: 32 PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM); 33 }; 34 } // end namespace llvm 35 36 #endif // LLVM_CODEGEN_UNREACHABLEBLOCKELIM_H 37