BFRegCopyBefore.cc

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/*
    Copyright (c) 2002-2014 Tampere University.
 
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/**
 * @file BFRegCopyBefore.cc
 *
 * Definition of BFRegCopyBefore class
 *
 * Creates a register-to-register copy before a move, modifying the source
 * of the original move into the temporaty register and making the source
 * of the temp move the original souce register.
 *
 * Used for temp-reg-copies of operand moves.
 *
 * @author Heikki Kultala 2014-2020(heikki.kultala-no.spam-tuni.fi)
 * @note rating: red
 */
 
#include "BFRegCopyBefore.hh"
#include "RegisterFile.hh"
#include "TerminalRegister.hh"
#include "BF2Scheduler.hh"
#include "MoveNode.hh"
#include "Move.hh"
#include "BFRemoveEdge.hh"
#include "BFConnectNodes.hh"
 
 
bool
BFRegCopyBefore::splitMove(BasicBlockNode& bbn) {
 
    std::set<const TTAMachine::RegisterFile*,
        TTAMachine::MachinePart::Comparator>
        rfs = sched_.possibleTempRegRFs(mn_, false, forbiddenRF_);
 
    // cannot create reg copy if no temp regs available.
    if (rfs.empty()) {
        return false;
    }
 
    const TTAMachine::RegisterFile& rf = **rfs.rbegin();
 
    int lastRegisterIndex = rf.size()-1;
    TTAMachine::Port* dstRFPort = rf.firstWritePort();
    TTAMachine::Port* srcRFPort = rf.firstReadPort();
 
    TTAProgram::TerminalRegister* tempWrite =
        new TTAProgram::TerminalRegister(*dstRFPort, lastRegisterIndex);
 
    TTAProgram::TerminalRegister* tempRead =
        new TTAProgram::TerminalRegister(*srcRFPort, lastRegisterIndex);
 
    regCopy_->move().setDestination(tempWrite);
    mn_.move().setSource(tempRead);
 
    auto iEdges = ddg().rootGraph()->inEdges(mn_);
    for (auto iEdge : iEdges) {
        if (!iEdge->isRegisterOrRA() || iEdge->headPseudo()) {
            continue;
        }
 
        //copy guard use edge to the regcopy.
        if (iEdge->guardUse() &&
            iEdge->dependenceType() == DataDependenceEdge::DEP_RAW) {
            MoveNode& tail = ddg().rootGraph()->tailNode(*iEdge);
            runPostChild(
                new BFConnectNodes(sched_, tail, *regCopy_, iEdge, true));
        } else if (iEdge->isRAW()) {
            MoveNode& tail = ddg().rootGraph()->tailNode(*iEdge);
            runPostChild(new BFRemoveEdge(sched_, tail, mn_, *iEdge));
            runPostChild(new BFConnectNodes(sched_, tail, *regCopy_, iEdge));
        }
    }
 
    auto oEdges = ddg().rootGraph()->outEdges(mn_);
    for (auto oEdge : oEdges) {
        if (!oEdge->isRegisterOrRA() || oEdge->tailPseudo()) {
            continue;
        }
        if (oEdge->dependenceType() == DataDependenceEdge::DEP_WAR &&
            !oEdge->guardUse()) {
            MoveNode& head = ddg().rootGraph()->headNode(*oEdge);
            runPostChild(new BFRemoveEdge(sched_, mn_, head, *oEdge));
            runPostChild(new BFConnectNodes(sched_, *regCopy_, head, oEdge));
        }
    }
 
    TCEString tempRegName = rf.name() + '.' +
        Conversion::toString(lastRegisterIndex);
 
    DataDependenceEdge* newEdge =
        new DataDependenceEdge(
            DataDependenceEdge::EDGE_REGISTER,
            DataDependenceEdge::DEP_RAW, tempRegName);
 
    runPostChild(new BFConnectNodes(sched_, *regCopy_, mn_, newEdge));
 
    createAntidepsForReg(
        *regCopy_, mn_, rf, lastRegisterIndex,
        tempRegName, bbn, ii()!= 0);
 
    return true;
}
 
void BFRegCopyBefore::undoSplit() {
    mn_.move().setSource(regCopy_->move().source().copy());
}