void TauWalkerState::reduceVarTaus()

in vm/jitrino/src/optimizer/simplifytaus.cpp [990:1154]
152 lines of code
27 McCabe index (conditional complexity)

void TauWalkerState::reduceVarTaus(Inst *inst)
{
    Opcode opcode = inst->getOpcode();
    switch (opcode) {
    case Op_LdVar:
        {
        }
        break;
    case Op_StVar:
        {
            Opnd *opnd = inst->getDst();

            for (U_32 exactTypeCount = 0; exactTypeCount < 2; ++exactTypeCount) {
                bool exactType = (exactTypeCount != 0);
            
                StlVectorSet<Type *> *reduceTypes = shouldReduceSsaOpnd(opnd, exactType);
                if (reduceTypes) {

                    if (Log::isEnabled()) {
                        Log::out() << "reducing StVar inst ";
                        inst->print(Log::out());
                        Log::out() << ::std::endl;
                    }
                    
                    StlVectorSet<Type *>::iterator 
                        iter = reduceTypes->begin(),
                        end = reduceTypes->end();
                    for ( ; iter != end; ++iter) {
                        Type *type = *iter;
                        VarOpnd *baseTauOpnd = getReductionTauBaseVar(opnd, type, exactType);
                        
                        if (Log::isEnabled()) {
                            Log::out() << "reducing StVar inst ";
                            inst->print(Log::out());
                            if (exactType)
                                Log::out() << " for exact type ";
                            else
                                Log::out() << " for type ";
                            if (type)
                                type->print(Log::out());
                            else
                                Log::out() << "NONNULL";
                            Log::out() << ::std::endl;
                        }
                        
                        Opnd *newDst = reduceSsaOpnd(inst->getDst(), baseTauOpnd, type, exactType);
                        SsaVarOpnd *newDstSsaVarOpnd = newDst->asSsaVarOpnd();
                        if (newDstSsaVarOpnd) {
                            if (!newDstSsaVarOpnd->getInst()) {
                                Opnd *newSrc = findReplacement(inst->getSrc(0), type, exactType);
                                Inst *newInst = irManager.getInstFactory().makeStVar(newDstSsaVarOpnd, 
                                                                                     newSrc);
                                assert(newInst->getDst()->getInst() == newInst);
                                assert(newDstSsaVarOpnd->getInst()->getDst() == newDstSsaVarOpnd);
                                newInst->insertAfter(inst);
                                if (Log::isEnabled()) {
                                    Log::out() << "reduced StVar inst ";
                                    inst->print(Log::out());
                                    Log::out() << " to inst ";
                                    newInst->print(Log::out());
                                    Log::out() << ::std::endl;
                                }
                            } else {
                                if (Log::isEnabled()) {
                                    Log::out() << "tau opnd ";
                                    newDstSsaVarOpnd->print(Log::out());
                                    Log::out() << " already has an inst ";
                                    newDstSsaVarOpnd->getInst()->print(Log::out());
                                    Log::out() << ::std::endl;
                                }
                            }
                        } else {
                            VarOpnd *newDstVarOpnd = newDst->asVarOpnd();
                            assert(newDstVarOpnd);
                            Opnd *newSrc = findReplacement(inst->getSrc(0), type, exactType);
                            Inst *newInst = irManager.getInstFactory().makeStVar(newDstVarOpnd, 
                                                                                 newSrc);
                            newInst->insertAfter(inst);
                            if (Log::isEnabled()) {
                                Log::out() << "reduced StVar inst ";
                                inst->print(Log::out());
                                Log::out() << " to inst ";
                                newInst->print(Log::out());
                                Log::out() << ::std::endl;
                            }
                        }
                    }
                }
            }
        }
        break;
    case Op_Phi:
        {
            Opnd *opnd = inst->getDst();

            for (U_32 exactTypeCount = 0; exactTypeCount < 2; ++exactTypeCount) {
                bool exactType = (exactTypeCount != 0);

                StlVectorSet<Type *> *reduceTypes = shouldReduceSsaOpnd(opnd, exactType);
                if (reduceTypes) {

                    if (Log::isEnabled()) {
                        Log::out() << "reducing Phi inst ";
                        inst->print(Log::out());
                        Log::out() << ::std::endl;
                    }
                    
                    StlVectorSet<Type *>::iterator 
                        iter = reduceTypes->begin(),
                        end = reduceTypes->end();
                    for ( ; iter != end; ++iter) {
                        Type *type = *iter;
                        VarOpnd *baseTauOpnd = getReductionTauBaseVar(opnd, type, exactType);
                        
                        if (Log::isEnabled()) {
                            Log::out() << "reducing Phi inst ";
                            inst->print(Log::out());
                            if (exactType)
                                Log::out() << " for exact type ";
                            else
                                Log::out() << " for type ";
                            if (type)
                                type->print(Log::out());
                            else
                                Log::out() << "NONNULL";
                            Log::out() << ::std::endl;
                        }
                        
                        Opnd *newDst = reduceSsaOpnd(inst->getDst(), baseTauOpnd, type, exactType);
                        if (!newDst->getInst()){
                            U_32 numOpnds = inst->getNumSrcOperands();
                            Opnd** newOpnds = new (mm) Opnd*[numOpnds];
                            for (U_32 i=0; i<numOpnds; ++i) {
                                Opnd *oldOpnd = inst->getSrc(i);
                                Opnd *newOpnd = reduceSsaOpnd(oldOpnd, baseTauOpnd, type, exactType);
                                newOpnds[i] = newOpnd;
                            }
                            Inst *newInst = irManager.getInstFactory().makePhi(newDst, numOpnds, newOpnds);
                            newInst->insertAfter(inst);

                            if (Log::isEnabled()) {
                                Log::out() << "reduced Phi inst ";
                                inst->print(Log::out());
                                Log::out() << " to inst ";
                                newInst->print(Log::out());
                                Log::out() << ::std::endl;
                            }
                        } else {
                            if (Log::isEnabled()) {
                                Log::out() << "tau opnd ";
                                newDst->print(Log::out());
                                Log::out() << " already has an inst ";
                                newDst->getInst()->print(Log::out());
                                Log::out() << ::std::endl;
                            }
                        }
                    }
                }
            }
        }
        break;
    default:
        break;
    }
}