1//===- AMDGPUUnifyDivergentExitNodes.h ------------------------------------===//
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 is a variant of the UnifyFunctionExitNodes pass. Rather than ensuring
10// there is at most one ret and one unreachable instruction, it ensures there is
11// at most one divergent exiting block.
12//
13// StructurizeCFG can't deal with multi-exit regions formed by branches to
14// multiple return nodes. It is not desirable to structurize regions with
15// uniform branches, so unifying those to the same return block as divergent
16// branches inhibits use of scalar branching. It still can't deal with the case
17// where one branch goes to return, and one unreachable. Replace unreachable in
18// this case with a return.
19//
20//===----------------------------------------------------------------------===//
21
22#ifndef LLVM_LIB_TARGET_AMDGPU_AMDGPUUNIFYDIVERGENTEXITNODES_H
23#define LLVM_LIB_TARGET_AMDGPU_AMDGPUUNIFYDIVERGENTEXITNODES_H
24
25#include "AMDGPU.h"
26
27namespace llvm {
28class AMDGPUUnifyDivergentExitNodesPass
29 : public PassInfoMixin<AMDGPUUnifyDivergentExitNodesPass> {
30public:
31 PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
32};
33
34} // end namespace llvm
35
36#endif // LLVM_LIB_TARGET_AMDGPU_AMDGPUUNIFYDIVERGENTEXITNODES_H
37