PostpassOperandSharer.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 PostpassOperandSharer.hh
 *
 * Declaration of PostpassOperandSharer class.
 *
 * This optimizer removes operand writes which are redundant due
 * other operations using same value. 
 * This is executed after the main scheduler, so this mainly helps
 * to reduce power consumption, not to improve performance.
 *
 * @author Heikki Kultala 2013 (hkultala-no.spam-cs.tut.fi)
 * @note rating: red
 */
 
#include "BasicBlockPass.hh"
#include "ControlFlowGraphPass.hh"
 
namespace TTAProgram {
    class BasicBlocK;
    class Move;
    class InstructionReferenceManager;
}
 
class PostpassOperandSharer : 
    public BasicBlockPass, public ControlFlowGraphPass {
 
public:
    PostpassOperandSharer(
        InterPassData& ipd, 
        TTAProgram::InstructionReferenceManager& irm) : 
        BasicBlockPass(ipd), ControlFlowGraphPass(ipd), irm_(&irm) {}
 
    virtual ~PostpassOperandSharer();
 
    virtual void handleBasicBlock(
        TTAProgram::BasicBlock& basicBlock,
        const TTAMachine::Machine& targetMachine,
        TTAProgram::InstructionReferenceManager& irm,
        BasicBlockNode* bbn = NULL);
 
    bool tryRemoveOperandWrite(
        TTAProgram::BasicBlock& basicBlock, 
        int insIndex, 
        TTAProgram::Move& move);
 
    static void printStats();
    
    virtual std::string shortDescription() const {
        return "Post-pass that reduced redundant operand writes";
    }
private:
    TTAProgram::InstructionReferenceManager* irm_;
    static unsigned int moveCount_;
    static unsigned int operandCount_;
    static unsigned int removedOperands_;
    static unsigned int registerReads_;
    static unsigned int triggerCannotRemove_;
};