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66 lines
2.2 KiB
C++
66 lines
2.2 KiB
C++
//===--- RDFDeadCode.h ----------------------------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// RDF-based generic dead code elimination.
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//
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// The main interface of this class are functions "collect" and "erase".
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// This allows custom processing of the function being optimized by a
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// particular consumer. The simplest way to use this class would be to
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// instantiate an object, and then simply call "collect" and "erase",
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// passing the result of "getDeadInstrs()" to it.
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// A more complex scenario would be to call "collect" first, then visit
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// all post-increment instructions to see if the address update is dead
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// or not, and if it is, convert the instruction to a non-updating form.
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// After that "erase" can be called with the set of nodes including both,
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// dead defs from the updating instructions and the nodes corresponding
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// to the dead instructions.
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#ifndef RDF_DEADCODE_H
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#define RDF_DEADCODE_H
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#include "RDFGraph.h"
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#include "RDFLiveness.h"
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#include "llvm/ADT/SetVector.h"
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namespace llvm {
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class MachineRegisterInfo;
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}
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namespace rdf {
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struct DeadCodeElimination {
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DeadCodeElimination(DataFlowGraph &dfg, MachineRegisterInfo &mri)
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: Trace(false), DFG(dfg), MRI(mri), LV(mri, dfg) {}
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bool collect();
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bool erase(const SetVector<NodeId> &Nodes);
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void trace(bool On) { Trace = On; }
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bool trace() const { return Trace; }
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SetVector<NodeId> getDeadNodes() { return DeadNodes; }
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SetVector<NodeId> getDeadInstrs() { return DeadInstrs; }
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DataFlowGraph &getDFG() { return DFG; }
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private:
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bool Trace;
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SetVector<NodeId> LiveNodes;
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SetVector<NodeId> DeadNodes;
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SetVector<NodeId> DeadInstrs;
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DataFlowGraph &DFG;
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MachineRegisterInfo &MRI;
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Liveness LV;
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bool isLiveInstr(const MachineInstr *MI) const;
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void scanInstr(NodeAddr<InstrNode*> IA, SetVector<NodeId> &WorkQ);
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void processDef(NodeAddr<DefNode*> DA, SetVector<NodeId> &WorkQ);
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void processUse(NodeAddr<UseNode*> UA, SetVector<NodeId> &WorkQ);
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};
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}
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#endif
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