BFShareOperands.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 BFShareOperands.cc
 *
 * Definition of BFShareOperands class
 *
 * Searches for potential operations to share operand with, and
 * then calls BFShareOperandWithScheduled to fo the actual operand sharing.
 *
 * @author Heikki Kultala 2014-2020(heikki.kultala-no.spam-tuni.fi)
 * @note rating: red
 */
 
#include "BFShareOperands.hh"
#include "DataDependenceGraph.hh"
#include "FunctionUnit.hh"
#include "Terminal.hh"
#include "Move.hh"
#include "Operation.hh"
#include "BF2Scheduler.hh"
#include "BF2ScheduleFront.hh"
#include "BFShareOperandWithScheduled.hh"
#include "HWOperation.hh"
#include "FUPort.hh"
 
bool BFShareOperands::operator()() {
    // TODO: alctually check the guards
    if (!mn_.move().isUnconditional()) {
        return false;
    }
 
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
    std::cerr << "\t\tShareOperands operator() called for:"
              << mn_.toString() <<  std::endl;
#endif
 
    if (sched_.currentFront()->illegalOperandShares_.find(&mn_) !=
        sched_.currentFront()->illegalOperandShares_.end()) {
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
        std::cerr << "\t\t\tIllegal operand share: " << mn_.toString()
                  << std::endl;
#endif
        return false;
    }
 
    bool didSomething = false;
    ProgramOperation& po = mn_.destinationOperation();
    const Operation& op = po.operation();
    const TTAMachine::FunctionUnit* forcedFU = po.scheduledFU();
 
    DataDependenceGraph::NodeSet siblings = ddg().regDepSiblings(mn_);
    for (auto i : siblings) {
        if (!i->isDestinationOperation()) {
            continue;
        }
 
        if (i->isScheduled()) {
            if (i->cycle() > maxCycle_) {
                continue;
            }
            // limit operand sharing for reasonable distances
            // TODO: use the cmd line parameter
            int ddglc = ddg().latestCycle(mn_, ii(), false, false);
            if (i->cycle() < ddglc - 5) {
                continue;
            }
 
            // try share with already scheduled
            const TTAProgram::Terminal& dt = i->move().destination();
            if (dt.isFUPort()) {
                const TTAMachine::FunctionUnit& fu = dt.functionUnit();
                if (!fu.hasOperation(op.name())) {
                    continue;
                }
                const TTAMachine::HWOperation* hwop = fu.operation(op.name());
                const TTAMachine::FUPort *sharedPort =
                    hwop->port(mn_.move().destination().operationIndex());
                if (sharedPort != &dt.port()) {
                    continue;
                }
                if (dt.isTriggering()) {
                    // TODO: is sibling commutative?
                    continue;
                }
                if (forcedFU != NULL) {
                    if (&fu == forcedFU) {
                        MoveNode* trigger =
                            BF2ScheduleFront::getSisterTrigger(
                                mn_, targetMachine());
                        if (trigger == &mn_) {
                            continue;
                        }
 
                        BFShareOperandWithScheduled* sows =
                            new BFShareOperandWithScheduled(sched_, *i, mn_);
                        if (runPreChild(sows)) {
                            didSomething = true;
                        }
                    }
                } else {
                    if (fu.hasOperation(op.name())) {
                        if (sched_.isTrigger(fu, mn_)) {
                            // TODO: change commutative
                            continue;
                        }
 
                        BFShareOperandWithScheduled* sows =
                            new BFShareOperandWithScheduled(sched_, *i, mn_);
                        if (runPreChild(sows)) {
                            didSomething = true;
                        }
                    }
                }
            }
        }
    }
    return didSomething;
}
 
void BFShareOperands::undoOnlyMe() {}
 
bool BFShareOperands::removedNode() { return false; }