BFDropPreShared.cc

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/**
 * @file BFDropPreShared.cc
 *
 * Definition of BFDropPreShared class
 *
 * Removes an operand write which is not needed because the operand is
 * loop-operand shared and put to the prolog of the loop.
 *
 * @author Heikki Kultala 2014-2020(heikki.kultala-no.spam-tuni.fi)
 * @note rating: red
 */
 
#include "BFDropPreShared.hh"
#include "DataDependenceGraph.hh"
#include "BF2Scheduler.hh"
#include "BFSwapOperands.hh"
#include "Operation.hh"
#include "Move.hh"
#include "Terminal.hh"
#include "MoveNodeSet.hh"
 
bool
BFDropPreShared::operator()() {
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
    std::cerr << "\tDropping pre-shared: " << mn_.toString() << std::endl;
#endif
    MoveNode* trigger = getSisterTrigger(mn_, targetMachine());
    if (trigger == &mn_) {
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
        std::cerr << "Cannot pre-share trigger operand, must swap operands"
                  << std::endl;
#endif
        ProgramOperationPtr destPO = mn_.destinationOperationPtr();
        const Operation& op = destPO->operation();
        int operandCount  = op.numberOfInputs();
        bool swapped = false;
        for (int i = 1 ; i <= operandCount && !swapped; i++) {
            int idx = mn_.move().destination().operationIndex();
            MoveNode& mn = destPO->inputNode(i).at(0);
            if (i != idx && op.canSwap(i, idx) &&
                !sched_.isPreLoopSharedOperand(mn)) {
                // TODO: force the indeces here
                BFSwapOperands* bfswo =
                    new BFSwapOperands(sched_, destPO, mn_, mn);
                if (runPreChild(bfswo)) {
                    swapped = true;
                }
            }
        }
        if (!swapped) {
            return false;
        }
    }
    ddg().dropNode(mn_);
    sched_.nodeKilled(mn_);
    return true;
}
 
void
BFDropPreShared::undoOnlyMe() {
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
    std::cerr << "\tUndoing dropping of pre-shared: " << mn_.toString()
              << std::endl;
#endif
    ddg().restoreNodeFromParent(mn_);
    sched_.nodeResurrected(mn_);
}