PreOptimizer.hh

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/*
    Copyright (c) 2002-2009 Tampere University.
 
    This file is part of TTA-Based Codesign Environment (TCE).
 
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/**
 * @file PreOptimizer.hh
 *
 * Declaration of PreOptimizer class.
 *
 * This optimizer does some peephole optimizations before actual scheduling:
 *
 * Removes unneeded predicate arithmetic by using
 * opposite guard instead where the guard is used.
 *
 * Changes registers of address calculations to eliminate entideps
 *
 * Removes adds of compile-time ocnstants
 *
 * @author Heikki Kultala 2009 (hkultala-no.spam-cs.tut.fi)
 * @note rating: red
 */
 
#ifndef TTA_PRE_OPTIMIZER_HH
#define TTA_PRE_OPTIMIZER_HH
 
#include "ProcedurePass.hh"
#include "ProgramPass.hh"
#include "ControlFlowGraphPass.hh"
#include "DataDependenceGraph.hh"
#include "ControlFlowGraph.hh"
 
namespace TTAProgram {
    class CodeSnippet;
    class Procedure;
    class Program;
    class InstructionReferenceManager;
    class Instruction;
}
 
namespace TTAMachine {
    class Machine;
}
 
class DataDependenceGraph;
class ProgramOperation;
 
class PreOptimizer:
    public ProcedurePass, public ProgramPass , public ControlFlowGraphPass {
 
public:
    PreOptimizer(InterPassData& data);
 
    void handleProgram(
        TTAProgram::Program& program, const TTAMachine::Machine& targetMachine);
 
    void handleProcedure(
        TTAProgram::Procedure& procedure,
        const TTAMachine::Machine& targetMachine);
 
    void handleControlFlowGraph(
        ControlFlowGraph& cfg, const TTAMachine::Machine& targetMachine);
 
    void handleCFGDDG(
        ControlFlowGraph& cfg,
        DataDependenceGraph& ddg);
 
    std::string shortDescription() const { 
        return "optimizes away guard nagation operations, "
            "uses opposite guards instead"; };
private:
    ControlFlowGraph::NodeSet inverseGuardsOfHeads(
        DataDependenceGraph& ddg,
        DataDependenceGraph::EdgeSet& oEdges);
 
    bool checkGuardReversalAllowed(
        DataDependenceGraph& ddg,
        DataDependenceGraph::EdgeSet& oEdges);
 
    bool tryToOptimizeAddressReg(
        DataDependenceGraph& ddg, ProgramOperation&po);
 
    ControlFlowGraph::NodeSet
    tryToRemoveXor(
        DataDependenceGraph& ddg, ProgramOperation& po,
        TTAProgram::InstructionReferenceManager* irm,
        ControlFlowGraph& cfg);
 
    ControlFlowGraph::NodeSet
    tryToRemoveEq(
        DataDependenceGraph& ddg, ProgramOperation& po,
        TTAProgram::InstructionReferenceManager* irm,
        ControlFlowGraph& cfg);
    
    ControlFlowGraph::NodeSet
    tryToRemoveGuardInversingOp(
        DataDependenceGraph& ddg, ProgramOperation& po,
        TTAProgram::InstructionReferenceManager* irm,
        ControlFlowGraph& cfg);
 
    bool cfgAllowsJumpReversal(
        TTAProgram::Instruction& ins, ControlFlowGraph& cfg);
 
    void tryToPrecalcConstantAdd(
        DataDependenceGraph& ddg, ProgramOperation& po);
 
};
 
#endif