BFShareOperandsLate.cc

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/*
    Copyright (c) 2002-2014 Tampere University.
 
    This file is part of TTA-Based Codesign Environment (TCE).
 
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/**
 * @file BFShareOperandsLate.cc
 *
 * Definition of BFShareOperandsLate class
 *
 * After scheduling a move,
 * Searches for potential operations to share operand with, and
 * then calls BFShareOperandLate to fo the actual operand sharing.
 *
 * @author Heikki Kultala 2014-2020(heikki.kultala-no.spam-tuni.fi)
 * @note rating: red
 */
 
 
#include "BFShareOperandsLate.hh"
#include "Move.hh"
#include "Terminal.hh"
#include "MoveNode.hh"
#include "SimpleResourceManager.hh"
#include "Instruction.hh"
#include "DataDependenceGraph.hh"
#include "BFShareOperandLate.hh"
#include "SchedulerCmdLineOptions.hh"
 
BFShareOperandsLate::BFShareOperandsLate(BF2Scheduler& sched, MoveNode& mn) :
    BFOptimization(sched), mn_(mn), operandShareDistance_(6) {
    SchedulerCmdLineOptions* opts =
        dynamic_cast<SchedulerCmdLineOptions*>(Application::cmdLineOptions());
    if (opts != NULL) {
        if (opts->operandShareDistance() > -1) {
            operandShareDistance_ = opts->operandShareDistance();
        }
    }
 
}
 
 
bool BFShareOperandsLate::operator()() {
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
    std::cerr << "\t\tTrying share operands late for: " << mn_.toString()
              << std::endl;
#endif
    TTAProgram::Move& currMove = mn_.move();
    TTAProgram::Terminal& currDest = currMove.destination();
    TTAProgram::Terminal& currSrc = currMove.source();
    if (currSrc.isImmediateRegister() ||
        currSrc.isFUPort()) {
        // lets not analyze yet when data in these change
        return false;
    }
 
    if (!currDest.isFUPort() ||
        currDest.isTriggering() ||
        currDest.isOpcodeSetting()) {
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
        std::cerr << "\t\t\tdest not operand port" << std::endl;
#endif
        return false;
    }
 
//    TTAMachine::RegisterFile* guardRF = NULL;
//    int guardIndex = -1;
//    bool guardInverted = false;
    if (!currMove.isUnconditional()) {
        return false;
        /*
        TTAMachine::Guard& guard = move.guard().guard();
        RegisterGuard* rg = dynamic_cast<TTAMachine::RegisterGuard*>(&guard);
        if (rg) {
            guardRF = rg->registerFile();
            guardIndex = rg->registerIndex();
            guardInverted = rg->isInverted();
        }
        */
    }
 
 
    int cycle = mn_.cycle();
    unsigned int idx = rm().instructionIndex(cycle);
    unsigned int limit = ii() ? std::min(ii(), idx+operandShareDistance_) :
        std::min((unsigned)rm().largestCycle()+1, idx+operandShareDistance_);
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
    std::cerr << "\t\t\tidx: " << idx << " limit:" << limit << std::endl;
#endif
    for (unsigned int i = idx; i < limit; i++) {
        const TTAProgram::Instruction& ins = *rm().instruction(i);
        for (int j = 0; j < ins.moveCount(); j++) {
            const TTAProgram::Move& laterMove = ins.move(j);
            const TTAProgram::Terminal& laterDest = laterMove.destination();
            if (&laterMove == &currMove) {
                continue;
            }
            if (!laterDest.equals(currDest)) {
                continue;
            }
 
            const TTAProgram::Terminal& laterSrc = laterMove.source();
            if (laterSrc.equals(currSrc)) {
                MoveNode& laterNode = ddg().nodeOfMove(laterMove);
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
                std::cerr << "\t\t\t\tOriginal scheduled move: " << mn_.toString()
                          << std::endl;
                std::cerr << "\t\t\t\tLate op sharing Could remove later move: "
                          << laterNode.toString() << std::endl;
#endif
                BFShareOperandLate* bfsol =
                    new BFShareOperandLate(sched_,laterNode, mn_);
                return runPostChild(bfsol);
            } else {
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
                std::cerr << "\t\t\tAnother move overwrites my dest"
                          << ddg().nodeOfMove(laterMove).toString() << std::endl;
#endif
                return false;
            }
        }
        for (int j = 0; j < ins.moveCount(); j++) {
            TTAProgram::Move& laterMove = ins.move(j);
            TTAProgram::Terminal& laterDest = laterMove.destination();
            // src is overwritten here
            if (laterDest.equals(currSrc)) {
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
                std::cerr << "\t\t\tOverwrites src: " <<
                    ddg().nodeOfMove(laterMove).toString() << std::endl;
#endif
                return false;
            }
        }
    }
    return false;
}
 
void BFShareOperandsLate::undoOnlyMe() {
 
}