BFPushMoveUp2.cc

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/**
 * @file BFPushMoveUp2.cc
 *
 * Definition of BFPushMoveUp2 class
 *
 * Tries to (recursively) reschedule move (and it's predecessors)
 * into earlier cycle.
 *
 * This version may unschedule whole operations and put them above some other
 * operations int he same FU.
 *
 * @author Heikki Kultala 2014-2020(heikki.kultala-no.spam-tuni.fi)
 * @note rating: red
 */
 
#include "BFPushMoveUp2.hh"
#include "DataDependenceGraph.hh"
#include "BFPushDepsUp.hh"
#include "Move.hh"
#include "BF2Scheduler.hh"
#include "BFScheduleBU.hh"
 
bool
BFPushMoveUp2::operator()() {
 
    if (lc_ == -1) {
        std::cerr << "incoming lc -1 on pushmoveup!"  << std::endl;
        assert(false);
    }
    if (mn_.move().isControlFlowMove()) {
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
        std::cerr << "\t\t|TCannot reschedule control flow move!" << std::endl;
#endif
        return false;
    }
 
    if (&mn_ == sched_.guardWriteNode()) {
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
        std::cerr << "\t\t|TCannot reschedule guard write move!" << std::endl;
#endif
        return false;
    }
 
    if (!mn_.isSourceOperation()) {
        return false;
    }
 
    // unschedule this (result) move
    ProgramOperation& po = mn_.sourceOperation();
    MoveNode* trigger = po.triggeringMove();
    unscheduleOriginal();
 
    int ddgLC = ddg().latestCycle(mn_,ii());
    int ddgEC = ddg().earliestCycle(mn_,ii());
 
    if (ddgLC == -1) {
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
        std::cerr << "ddg latest cycle -1 in pushmoveup2 of:"
                  << mn_.toString() << std::endl;
#endif
        returnOriginal();
        return false;
    }
 
    int lc = std::min(lc_, ddgLC);
 
    if (ddgEC > lc) {
        DataDependenceGraph::NodeSet unschedOperands;
        DataDependenceGraph::NodeSet unschedResults;
        // undo the inputs
        for (int i = 0; i < po.inputMoveCount(); i++) {
            MoveNode& operand = po.inputMove(i);
            if (operand.isScheduled()) {
                if (!runPostChild(new BFUnscheduleMove(sched_, operand))) {
                    undo();
                    return false;
                } else {
                    unschedOperands.insert(&operand);
                }
            }
        }
 
        for (int i = 0; i < po.outputMoveCount(); i++) {
            MoveNode& res = po.outputMove(i);
            if (res.isScheduled() &&
                (res.cycle() > lc ||
                 (isLoopBypass(res) && res.cycle()+((signed)ii()) > lc))) {
                if (!runPostChild(new BFUnscheduleMove(sched_, res))) {
                    undo();
                    return false;
                } else {
                    unschedResults.insert(&res);
                }
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
            } else {
                std::cerr << "res which is not scheduled:" << res.toString()
                          << std::endl;
#endif
            }
        }
 
        // now whole op is not scheduled?
 
        // reschedule other results
        for (int i = po.outputMoveCount()-1; i >= 0; i--) {
            MoveNode& res = po.outputMove(i);
            if (AssocTools::containsKey(unschedResults, &res)) {
                int myLC = lc - isLoopBypass(res) * ii();
                if (!runPostChild(
                        new BFScheduleBU(
                            sched_, res, myLC, false, false, false))) {
                    undo();
                    return false;
                }
            }
        }
 
        // reschedule me.
        if (!runPostChild(
                new BFScheduleBU(sched_, mn_, lc, false, false, false))) {
            undo();
            return false;
        }
 
        // reschdule trigger
        if (AssocTools::containsKey(unschedOperands, trigger)) {
            if (!runPostChild(
                    new BFScheduleBU(
                        sched_, *trigger, lc, false, false, false))) {
                undo();
                return false;
            }
        }
 
        // reschedule other operands
        for (int i = 0; i < po.inputMoveCount(); i++) {
            MoveNode& operand = po.inputMove(i);
            if (&operand != trigger) {
                if (AssocTools::containsKey(unschedOperands, &operand)) {
                    if (!runPostChild(
                            new BFScheduleBU(
                                sched_, operand, lc, false, false, false))) {
                        undo();
                        return false;
                    }
                }
            }
        }
    } else {
        undo();
        return false;
    }
    assert(mn_.isScheduled());
    return true;
}
 
bool BFPushMoveUp2::isLoopBypass(MoveNode&mn) {
    auto inEdges = ddg().operationInEdges(mn);
    for (auto e: inEdges) {
        if (e->isBackEdge()) {
            return true;
        }
    }
 
    return false;
}