Andrew Scull | 5e1ddfa | 2018-08-14 10:06:54 +0100 | [diff] [blame] | 1 | //===-- UnreachableBlockElim.h - Remove unreachable blocks for codegen --===// |
| 2 | // |
Andrew Walbran | 16937d0 | 2019-10-22 13:54:20 +0100 | [diff] [blame] | 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 |
Andrew Scull | 5e1ddfa | 2018-08-14 10:06:54 +0100 | [diff] [blame] | 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_LIB_CODEGEN_UNREACHABLEBLOCKELIM_H |
| 23 | #define LLVM_LIB_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_LIB_CODEGEN_UNREACHABLEBLOCKELIM_H |