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1//===--- RDFDeadCode.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-exception6//7//===----------------------------------------------------------------------===//8//9// RDF-based generic dead code elimination.10//11// The main interface of this class are functions "collect" and "erase".12// This allows custom processing of the function being optimized by a13// particular consumer. The simplest way to use this class would be to14// instantiate an object, and then simply call "collect" and "erase",15// passing the result of "getDeadInstrs()" to it.16// A more complex scenario would be to call "collect" first, then visit17// all post-increment instructions to see if the address update is dead18// or not, and if it is, convert the instruction to a non-updating form.19// After that "erase" can be called with the set of nodes including both,20// dead defs from the updating instructions and the nodes corresponding21// to the dead instructions.22 23#ifndef RDF_DEADCODE_H24#define RDF_DEADCODE_H25 26#include "llvm/CodeGen/RDFGraph.h"27#include "llvm/CodeGen/RDFLiveness.h"28#include "llvm/ADT/SetVector.h"29 30namespace llvm {31 class MachineRegisterInfo;32 33namespace rdf {34 struct DeadCodeElimination {35 DeadCodeElimination(DataFlowGraph &dfg, MachineRegisterInfo &mri)36 : Trace(false), DFG(dfg), MRI(mri), LV(mri, dfg) {}37 38 bool collect();39 bool erase(const SetVector<NodeId> &Nodes);40 void trace(bool On) { Trace = On; }41 bool trace() const { return Trace; }42 43 SetVector<NodeId> getDeadNodes() { return DeadNodes; }44 SetVector<NodeId> getDeadInstrs() { return DeadInstrs; }45 DataFlowGraph &getDFG() { return DFG; }46 47 private:48 bool Trace;49 SetVector<NodeId> LiveNodes;50 SetVector<NodeId> DeadNodes;51 SetVector<NodeId> DeadInstrs;52 DataFlowGraph &DFG;53 MachineRegisterInfo &MRI;54 Liveness LV;55 56 template<typename T> struct SetQueue;57 58 bool isLiveInstr(NodeAddr<StmtNode*> S) const;59 void scanInstr(NodeAddr<InstrNode*> IA, SetQueue<NodeId> &WorkQ);60 void processDef(NodeAddr<DefNode*> DA, SetQueue<NodeId> &WorkQ);61 void processUse(NodeAddr<UseNode*> UA, SetQueue<NodeId> &WorkQ);62 };63} // namespace rdf64} // namespace llvm65 66#endif67