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 | |