void IpfCfgCodeSelector::genSwitchEdges(U_32 tailNodeId, U_32 numTargets, U_32 *targets, double *probs, U_32 defaultTarget) { BbNode *tailNode = (BbNode *)nodes[tailNodeId]; InstVector &insts = tailNode->getInsts(); Inst *switchInst = insts.back(); Opnd *defTargetImm = switchInst->getOpnd(POS_SWITCH_DEFAULT); ConstantRef *constantRef = (ConstantRef *) switchInst->getOpnd(POS_SWITCH_TABLE); SwitchConstant *switchConstant = (SwitchConstant *)constantRef->getConstant(); Edge *defedge = NULL; Edge *edge = NULL; bool defadded = false; U_32 i = 0; IPF_LOG << " Generate Switch tailNodeId=" << tailNodeId << "; defaultTarget=" << defaultTarget << endl; defedge = new(mm) Edge(nodes[tailNodeId], nodes[defaultTarget], probs[defaultTarget], EDGE_BRANCH); defedge->insert(); for(i=0; i<numTargets; i++) { if(targets[i] == defaultTarget) { defTargetImm->setValue(i); switchConstant->addEdge(defedge); defadded = true; IPF_LOG << " default: " << i << endl; continue; } IPF_LOG << " case " << i << ": " << targets[i] << endl; edge = new(mm) Edge(nodes[tailNodeId], nodes[targets[i]], probs[i], EDGE_BRANCH); edge->insert(); switchConstant->addEdge(edge); } if (!defadded) { defTargetImm->setValue(i); switchConstant->addEdge(defedge); defadded = true; IPF_LOG << " default: " << i << endl; } }
Opnd* OpndUtils::findImmediateSource(Opnd* opnd) { Opnd* res = opnd; while (!res->isPlacedIn(OpndKind_Imm)) { Inst* defInst = res->getDefiningInst(); if (!defInst || defInst->getMnemonic()!=Mnemonic_MOV) { return NULL; } res = defInst->getOpnd(1); } return res; }
//_________________________________________________________________________________________________ void DCE::runImpl() { bool early = false; getArg("early", early); if (early && !irManager->getCGFlags()->earlyDCEOn) { return; } irManager->updateLivenessInfo(); irManager->calculateOpndStatistics(); BitSet ls(irManager->getMemoryManager(), irManager->getOpndCount()); const Nodes& nodes = irManager->getFlowGraph()->getNodesPostOrder(); #ifdef ORDER MemoryManager mm("dce_parents"); U_32 opndCount = irManager->getOpndCount(); bool * isParentOpnd = new(mm) bool [opndCount]; memset(isParentOpnd, 0, sizeof(bool) * opndCount); for (Nodes::const_iterator it = nodes.begin(),end = nodes.end(); it!=end; ++it) { Node* node = *it; for (Inst * inst=(Inst*)node->getLastInst(); inst!=NULL; inst=inst->getPrevInst()) { Opnd* load_obj = inst->getParentObjectLoad(); if (load_obj) { isParentOpnd[load_obj->getId()] = true; } Opnd* store_obj = inst->getParentObjectStore(); if (store_obj) { isParentOpnd[store_obj->getId()] = true; } } } #endif for (Nodes::const_iterator it = nodes.begin(),end = nodes.end(); it!=end; ++it) { Node* node = *it; if (node->isBlockNode()) { //Here we'll try to remove redundant branches that could appear after //branch translations. All such branches are supposed to be conditional. Inst * inst = (Inst *)node->getLastInst(); if(inst && node->getOutEdges().size() > 1) { Edges edges = node->getOutEdges(); for (Edges::const_iterator ite1 = ++edges.begin(), end = edges.end(); ite1 != end; ++ite1) { for (Edges::const_iterator ite2 = edges.begin(); ite1 != ite2; ++ite2) { Edge *edge1 = *ite1; Edge *edge2 = *ite2; assert(edge1 != edge2); //If this condition is satisfied then there are at least two branches with //the same destination if (edge1->getTargetNode() == edge2->getTargetNode()) { //Check that edges are conditional and the last instruction is branch, //the other situations are not permitted at the moment assert(inst->hasKind(Inst::Kind_BranchInst)); assert(edge1->getKind() == Edge::Kind_True || edge1->getKind() == Edge::Kind_False); assert(edge2->getKind() == Edge::Kind_True || edge2->getKind() == Edge::Kind_False); //Remove last instruction if it is a branch inst->unlink(); irManager->getFlowGraph()->removeEdge(edge2); } } } } irManager->getLiveAtExit(node, ls); for (Inst * inst=(Inst*)node->getLastInst(), * prevInst=NULL; inst!=NULL; inst=prevInst) { prevInst=inst->getPrevInst(); // Prevent debug traps or instructions with side effects // like (MOVS) from being removed. bool deadInst=!inst->hasSideEffect() && (inst->getMnemonic() != Mnemonic_INT3); #ifdef ORDER //yzm for (unsigned int i = 0 ; i < inst->getOpndCount() ; i ++) { Opnd* opnd = inst->getOpnd(i); if (isParentOpnd[opnd->getId()]) deadInst = false; } #endif if (deadInst) { if (inst->hasKind(Inst::Kind_CopyPseudoInst)) { Opnd * opnd=inst->getOpnd(1); if (opnd->getType()->isFP() && opnd->getDefiningInst()!=NULL && opnd->getDefiningInst()->getMnemonic()==Mnemonic_CALL) { deadInst=false; } } if (deadInst) { Inst::Opnds opnds(inst, Inst::OpndRole_All); for (Inst::Opnds::iterator ito = opnds.begin(); ito != opnds.end(); ito = opnds.next(ito)) { Opnd * opnd = inst->getOpnd(ito); if ((ls.getBit(opnd->getId()) && (inst->getOpndRoles(ito) & Inst::OpndRole_Def)) || (((opnd->getMemOpndKind()&(MemOpndKind_Heap|MemOpndKind_StackManualLayout))!=0) && (inst->getMnemonic() != Mnemonic_LEA))) { deadInst=false; break; } } } } if (deadInst) { inst->unlink(); } else { irManager->updateLiveness(inst, ls); } } irManager->getLiveAtEntry(node)->copyFrom(ls); } } irManager->eliminateSameOpndMoves(); irManager->getFlowGraph()->purgeEmptyNodes(); irManager->getFlowGraph()->mergeAdjacentNodes(true, false); irManager->getFlowGraph()->purgeUnreachableNodes(); irManager->packOpnds(); irManager->invalidateLivenessInfo(); }
//___________________________________________________________________________________________________ void EarlyPropagation::runImpl() { irManager->updateLoopInfo(); U_32 opndCount=irManager->getOpndCount(); MemoryManager mm("early_prop"); OpndInfo * opndInfos = new(mm) OpndInfo[opndCount]; Node * currentLoopHeader = NULL; bool anyInstHandled=false; LoopTree* lt = irManager->getFlowGraph()->getLoopTree(); const Nodes& postOrdered = irManager->getFlowGraph()->getNodesPostOrder(); for (Nodes::const_reverse_iterator it = postOrdered.rbegin(), end = postOrdered.rend(); it!=end; ++it) { Node * node=*it; if (!node->isBlockNode()) { continue; } Node * loopHeader = lt->getLoopHeader(node, false); if (currentLoopHeader != loopHeader){ currentLoopHeader = loopHeader; for (U_32 i = 0; i < opndCount; ++i) if (opndInfos[i].sourceOpndId != EmptyUint32) opndInfos[i].defCount++; } for (Inst * inst = (Inst*)node->getFirstInst(); inst != NULL; inst=inst->getNextInst()){ bool assignedOpndPropagated = false; Inst::Opnds opnds(inst, Inst::OpndRole_All); for (Inst::Opnds::iterator it = opnds.begin(); it != opnds.end(); it = opnds.next(it)){ Opnd * opnd=inst->getOpnd(it); U_32 roles=inst->getOpndRoles(it); U_32 opndId = opnd->getId(); OpndInfo& opndInfo = opndInfos[opndId]; U_32 mask = 0; if (roles & Inst::OpndRole_Def){ ++opndInfo.defCount; }else if (roles & Inst::OpndRole_Use){ if (opndInfo.sourceOpndId != EmptyUint32){ if (opndInfo.sourceOpndDefCountAtCopy < opndInfos[opndInfo.sourceOpndId].defCount) opndInfo.sourceOpndId = EmptyUint32; else{ Opnd * srcOpnd = irManager->getOpnd(opndInfo.sourceOpndId); Constraint co = srcOpnd->getConstraint(Opnd::ConstraintKind_Location); if (co.getKind() == OpndKind_Mem){ mask = (1<<it)-1; if ((roles & Inst::OpndRole_Explicit) == 0 || inst->hasKind(Inst::Kind_PseudoInst) || irManager->isGCSafePoint(inst) || opndInfo.sourceInst != inst->getPrevInst() || assignedOpndPropagated || (inst->getConstraint(it, mask, co.getSize())&co).isNull() ) opndInfo.sourceOpndId = EmptyUint32; assignedOpndPropagated = true; } } } } if (opndInfo.defCount > 1){ opndInfo.sourceOpndId = EmptyUint32; } } /* Here is the previous version to test whether the inst is copy or not. bool isCopy = inst->getMnemonic() == Mnemonic_MOV ||( (inst->getMnemonic() == Mnemonic_ADD || inst->getMnemonic() == Mnemonic_SUB) && inst->getOpnd(3)->isPlacedIn(OpndKind_Imm) && inst->getOpnd(3)->getImmValue()==0 && inst->getOpnd(3)->getRuntimeInfo()==NULL ); It considered special case of 'dst = src +/- 0' as copy. In fact there are more similar cases like 'IMUL src, 1 ; shift src, 0' etc. Such checks are obsolete now, Should as peephole takes care about such copies. Anyway, the code above had a bug: 'inst->getOpnd(3)' crashes in instructions in native form (like ADD def_use, use). */ const bool isCopy = inst->getMnemonic() == Mnemonic_MOV; if (isCopy){ // CopyPseudoInst or mov Opnd * defOpnd = inst->getOpnd(0); Opnd * srcOpnd = inst->getOpnd(1); U_32 defOpndId = defOpnd->getId(); OpndInfo * opndInfo = opndInfos + defOpndId; bool instHandled=false; bool typeConvOk = isTypeConversionAllowed(srcOpnd, defOpnd); if (typeConvOk && opndInfo->defCount == 1 && ! srcOpnd->isPlacedIn(OpndKind_Reg)){ if (!defOpnd->hasAssignedPhysicalLocation()){ opndInfo->sourceInst = inst; opndInfo->sourceOpndId = srcOpnd->getId(); instHandled=true; } } if (instHandled){ if (opndInfos[opndInfo->sourceOpndId].sourceOpndId != EmptyUint32) opndInfo->sourceOpndId = opndInfos[opndInfo->sourceOpndId].sourceOpndId; opndInfo->sourceOpndDefCountAtCopy = opndInfos[opndInfo->sourceOpndId].defCount; anyInstHandled=true; } } } } if (anyInstHandled){ Opnd ** replacements = new(mm) Opnd* [opndCount]; memset(replacements, 0, sizeof(Opnd*) * opndCount); bool hasReplacements = false; for (U_32 i = 0; i < opndCount; ++i){ if (opndInfos[i].sourceOpndId != EmptyUint32){ Inst * inst = opndInfos[i].sourceInst; if (inst !=NULL){ inst->unlink(); } if (opndInfos[i].sourceOpndId != i){ Opnd* origOpnd= irManager->getOpnd(i); Opnd* replacementOpnd = irManager->getOpnd(opndInfos[i].sourceOpndId); assert(isTypeConversionAllowed(replacementOpnd, origOpnd)); if (origOpnd->getType()->isUnmanagedPtr() && replacementOpnd->getType()->isInteger()) { replacementOpnd->setType(origOpnd->getType()); }/* else if (origOpnd->getType()->isObject() && replacementOpnd->getType()->isUnmanagedPtr()) { replacementOpnd->setType(origOpnd->getType()); }*/ replacements[i] = replacementOpnd; hasReplacements = true; } } } if (hasReplacements){ const Nodes& postOrdered = irManager->getFlowGraph()->getNodesPostOrder(); for (Nodes::const_reverse_iterator it = postOrdered.rbegin(), end = postOrdered.rend(); it!=end; ++it) { Node * node=*it; if (!node->isBlockNode()) { continue; } for (Inst * inst = (Inst*)node->getFirstInst(); inst != NULL; inst=inst->getNextInst()){ inst->replaceOpnds(replacements); } } } } }
PeepHoleOpt::Changed PeepHoleOpt::handleInst_SETcc(Inst* inst) { if (((BasicBlock*)inst->getNode())->getLayoutSucc() == NULL) { Mnemonic mn = inst->getMnemonic(); Inst* prev = inst->getPrevInst(); Inst *next = inst->getNextInst(); Node *currNode = inst->getNode(); bool methodMarkerOccur = false; MethodMarkerPseudoInst* methodMarker = NULL; // ignoring instructions that have no effect and saving method markers to correct them during optimizations while (next == NULL || next->getKind() == Inst::Kind_MethodEndPseudoInst || next->getMnemonic() == Mnemonic_JMP) { if (next == NULL) { currNode = currNode->getOutEdge(Edge::Kind_Unconditional)->getTargetNode(); if (currNode->getKind() == Node::Kind_Exit) return Changed_Nothing; next = (Inst*) currNode->getFirstInst(); } else { if (next->getKind() == Inst::Kind_MethodEndPseudoInst) { //max 1 saved method marker if (methodMarkerOccur) { return Changed_Nothing; } methodMarker = (MethodMarkerPseudoInst*)next; methodMarkerOccur = true; } next = next->getNextInst(); } } Inst *next2 = next->getNextInst(); bool step1 = true; currNode = inst->getNode(); while (currNode != next->getNode()) { currNode = currNode->getOutEdge(Edge::Kind_Unconditional)->getTargetNode(); if (currNode->getInDegree()!=1) { step1 = false; break; } } // step1: // ------------------------------------------ // MOV opnd, 0 MOV opnd2, 0 // SETcc opnd -> SETcc opnd2 // MOV opnd2, opnd // ------------------------------------------ // nb: applicable if opnd will not be used further if (step1 && prev!= NULL && prev->getMnemonic() == Mnemonic_MOV && next!= NULL && next->getMnemonic() == Mnemonic_MOV) { Opnd *prevopnd1, *prevopnd2, *nextopnd1, *nextopnd2, *setopnd; if (prev->getKind() == Inst::Kind_CopyPseudoInst) { prevopnd1 = prev->getOpnd(0); prevopnd2 = prev->getOpnd(1); } else { Inst::Opnds prevuses(prev, Inst::OpndRole_Explicit|Inst::OpndRole_Use); Inst::Opnds prevdefs(prev, Inst::OpndRole_Explicit|Inst::OpndRole_Def); prevopnd1 = prev->getOpnd(prevdefs.begin()); prevopnd2 = prev->getOpnd(prevuses.begin()); } if (next->getKind() == Inst::Kind_CopyPseudoInst) { nextopnd1 = next->getOpnd(0); nextopnd2 = next->getOpnd(1); } else { Inst::Opnds nextuses(next, Inst::OpndRole_Explicit|Inst::OpndRole_Use); Inst::Opnds nextdefs(next, Inst::OpndRole_Explicit|Inst::OpndRole_Def); nextopnd1 = next->getOpnd(nextdefs.begin()); nextopnd2 = next->getOpnd(nextuses.begin()); } Inst::Opnds setdefs(inst, Inst::OpndRole_Explicit|Inst::OpndRole_Def); setopnd = inst->getOpnd(setdefs.begin()); if (isReg(nextopnd1) && prevopnd1->getId() == setopnd->getId() && setopnd->getId() == nextopnd2->getId() && isImm(prevopnd2) && prevopnd2->getImmValue() == 0 ) { BitSet ls(irManager->getMemoryManager(), irManager->getOpndCount()); irManager->updateLivenessInfo(); irManager->getLiveAtExit(next->getNode(), ls); for (Inst* i = (Inst*)next->getNode()->getLastInst(); i!=next; i = i->getPrevInst()) { irManager->updateLiveness(i, ls); } bool opndNotUsed = !ls.getBit(setopnd->getId()); if (opndNotUsed) { if (nextopnd1->getRegName() != RegName_Null && Constraint::getAliasRegName(nextopnd1->getRegName(), OpndSize_8) == RegName_Null) { nextopnd1->assignRegName(setopnd->getRegName()); } irManager->newInst(Mnemonic_MOV, nextopnd1, prevopnd2)->insertBefore(inst); irManager->newInst(mn, nextopnd1)->insertBefore(inst); prev->unlink(); inst->unlink(); next->unlink(); return Changed_Node; } } } // step2: // -------------------------------------------------------------- // MOV opnd, 0 Jcc smwh Jcc smwh // SETcc opnd -> BB1: v BB1: // CMP opnd, 0 ... // Jcc smwh CMP opnd, 0 // BB1: Jcc smwh // -------------------------------------------------------------- // nb: applicable if opnd will not be used further // nb: conditions of new jumps are calculated from conditions of old jump and set instructions if (prev!= NULL && prev->getMnemonic() == Mnemonic_MOV && next!= NULL && (next->getMnemonic() == Mnemonic_CMP || next->getMnemonic() == Mnemonic_TEST) && next2!= NULL && (next2->getMnemonic() == Mnemonic_JG || next2->getMnemonic() == Mnemonic_JE || next2->getMnemonic() == Mnemonic_JNE) ) { Opnd* movopnd1; Opnd* movopnd2; if (prev->getKind() == Inst::Kind_CopyPseudoInst) { movopnd1 = prev->getOpnd(0); movopnd2 = prev->getOpnd(1); } else { Inst::Opnds movuses(prev, Inst::OpndRole_Explicit|Inst::OpndRole_Use); Inst::Opnds movdefs(prev, Inst::OpndRole_Explicit|Inst::OpndRole_Def); movopnd1 = prev->getOpnd(movdefs.begin()); movopnd2 = prev->getOpnd(movuses.begin()); } Inst::Opnds cmpuses(next, Inst::OpndRole_Explicit|Inst::OpndRole_Use); Opnd* cmpopnd1 = next->getOpnd(cmpuses.begin()); Opnd* cmpopnd2 = next->getOpnd(cmpuses.next(cmpuses.begin())); if ( isImm(movopnd2) && movopnd2->getImmValue() == 0 && movopnd1->getId() == cmpopnd1->getId() && //case CMP: (next->getMnemonic() != Mnemonic_CMP || (isImm(cmpopnd2) && cmpopnd2->getImmValue() == 0)) && //case TEST: (next->getMnemonic() != Mnemonic_TEST || cmpopnd1->getId() == cmpopnd2->getId()) ) { BitSet ls(irManager->getMemoryManager(), irManager->getOpndCount()); irManager->updateLivenessInfo(); irManager->getLiveAtExit(next2->getNode(), ls); bool opndNotUsed = !ls.getBit(movopnd1->getId()); if (opndNotUsed) { BranchInst* br = (BranchInst*) next2; Mnemonic newjumpmn = Mnemonic_JZ; if (next2->getMnemonic() == Mnemonic_JE) { switch (mn) { case Mnemonic_SETG: newjumpmn = Mnemonic_JLE; break; case Mnemonic_SETE: newjumpmn = Mnemonic_JNE; break; case Mnemonic_SETL: newjumpmn = Mnemonic_JGE; break; case Mnemonic_SETNE: newjumpmn = Mnemonic_JE; break; default: assert(0); break; } } else { switch (mn) { case Mnemonic_SETG: newjumpmn = Mnemonic_JG; break; case Mnemonic_SETE: newjumpmn = Mnemonic_JE; break; case Mnemonic_SETL: newjumpmn = Mnemonic_JL; break; case Mnemonic_SETNE: newjumpmn = Mnemonic_JNE; break; default: assert(0); break; } } if (inst->getNode()->getId() != next->getNode()->getId()) { ControlFlowGraph* cfg = irManager->getFlowGraph(); cfg->removeEdge(inst->getNode()->getOutEdge(Edge::Kind_Unconditional)); double trueEdgeProb = next2->getNode()->getOutEdge(Edge::Kind_True)->getEdgeProb(); double falseEdgeProb = next2->getNode()->getOutEdge(Edge::Kind_False)->getEdgeProb(); cfg->addEdge(inst->getNode(), br->getTrueTarget(), trueEdgeProb); cfg->addEdge(inst->getNode(), br->getFalseTarget(), falseEdgeProb); irManager->newBranchInst(newjumpmn, br->getTrueTarget(), br->getFalseTarget())->insertAfter(inst); if (methodMarkerOccur) { inst->getNode()->appendInst(irManager->newMethodEndPseudoInst(methodMarker->getMethodDesc())); } prev->unlink(); inst->unlink(); cfg->purgeUnreachableNodes(); } else { irManager->newBranchInst(newjumpmn, br->getTrueTarget(), br->getFalseTarget())->insertAfter(next2); prev->unlink(); inst->unlink(); next->unlink(); next2->unlink(); } return Changed_Node; }// endif opndNotUsed } } } return Changed_Nothing; }
PeepHoleOpt::Changed PeepHoleOpt::handleInst_MOV(Inst* inst) { Node* node = inst->getNode(); if (((BasicBlock*)node)->getLayoutSucc() == NULL) { Inst *next = inst->getNextInst(); Node *currNode = node; bool methodMarkerOccur = false; MethodMarkerPseudoInst* methodMarker = NULL; // ignoring instructions that have no effect and saving method markers to correct them during optimizations while (next == NULL || next->getKind() == Inst::Kind_MethodEndPseudoInst || next->getMnemonic() == Mnemonic_JMP) { if (next == NULL) { currNode = currNode->getOutEdge(Edge::Kind_Unconditional)->getTargetNode(); if (currNode->getKind() == Node::Kind_Exit) return Changed_Nothing; next = (Inst*) currNode->getFirstInst(); } else { if (next->getKind() == Inst::Kind_MethodEndPseudoInst) { //max 1 saved method marker if (methodMarkerOccur) { return Changed_Nothing; } methodMarker = (MethodMarkerPseudoInst*)next; methodMarkerOccur = true; } next = next->getNextInst(); } } Inst *jump = next->getNextInst(); bool step1 = true; currNode = node; while (currNode != next->getNode()) { currNode = currNode->getOutEdge(Edge::Kind_Unconditional)->getTargetNode(); if (currNode->getInDegree()!=1) { step1 = false; break; } } // step1: // --------------------------------------------- // MOV opnd, opnd2 MOV opnd3, opnd2 // MOV opnd3, opnd -> // --------------------------------------------- // nb: applicable if opnd will not be used further if (step1 && next->getMnemonic() == Mnemonic_MOV) { Opnd *movopnd1, *movopnd2, *nextmovopnd1, *nextmovopnd2; bool isInstCopyPseudo = (inst->getKind() == Inst::Kind_CopyPseudoInst); if (isInstCopyPseudo) { movopnd1 = inst->getOpnd(0); movopnd2 = inst->getOpnd(1); } else { Inst::Opnds movuses(inst, Inst::OpndRole_Explicit|Inst::OpndRole_Use); Inst::Opnds movdefs(inst, Inst::OpndRole_Explicit|Inst::OpndRole_Def); movopnd1 = inst->getOpnd(movdefs.begin()); movopnd2 = inst->getOpnd(movuses.begin()); } bool isNextCopyPseudo = (next->getKind() == Inst::Kind_CopyPseudoInst); if (isNextCopyPseudo) { nextmovopnd1 = next->getOpnd(0); nextmovopnd2 = next->getOpnd(1); } else { Inst::Opnds nextmovuses(next, Inst::OpndRole_Explicit|Inst::OpndRole_Use); Inst::Opnds nextmovdefs(next, Inst::OpndRole_Explicit|Inst::OpndRole_Def); nextmovopnd1 = next->getOpnd(nextmovdefs.begin()); nextmovopnd2 = next->getOpnd(nextmovuses.begin()); } if (movopnd1->getId() == nextmovopnd2->getId() && !isMem(movopnd2) && !isMem(nextmovopnd1) && !isMem(movopnd1) ) { BitSet ls(irManager->getMemoryManager(), irManager->getOpndCount()); irManager->updateLivenessInfo(); irManager->getLiveAtExit(next->getNode(), ls); for (Inst* i = (Inst*)next->getNode()->getLastInst(); i!=next; i = i->getPrevInst()) { irManager->updateLiveness(i, ls); } bool dstNotUsed = !ls.getBit(movopnd1->getId()); if (dstNotUsed) { if (isInstCopyPseudo && isNextCopyPseudo) irManager->newCopyPseudoInst(Mnemonic_MOV, nextmovopnd1, movopnd2)->insertAfter(inst); else irManager->newInst(Mnemonic_MOV, nextmovopnd1, movopnd2)->insertAfter(inst); inst->unlink(); next->unlink(); return Changed_Node; } } } // step2: // -------------------------------------------------------------- // MOV opnd, 0/1 Jmp smwh/BB1 Jmp smwh/BB1 // CMP opnd, 0 -> CMP opnd, 0 v // Jcc smwh Jcc smwh // BB1: BB1: // -------------------------------------------------------------- // nb: applicable if opnd will not be used further if (next->getMnemonic() == Mnemonic_CMP && jump!= NULL && (jump->getMnemonic() == Mnemonic_JE || jump->getMnemonic() == Mnemonic_JNE)) { Opnd *movopnd1, *movopnd2; if (inst->getKind() == Inst::Kind_CopyPseudoInst) { movopnd1 = inst->getOpnd(0); movopnd2 = inst->getOpnd(1); } else { Inst::Opnds movuses(inst, Inst::OpndRole_Explicit|Inst::OpndRole_Use); Inst::Opnds movdefs(inst, Inst::OpndRole_Explicit|Inst::OpndRole_Def); movopnd1 = inst->getOpnd(movdefs.begin()); movopnd2 = inst->getOpnd(movuses.begin()); } Inst::Opnds cmpuses(next, Inst::OpndRole_Explicit|Inst::OpndRole_Use); Opnd* cmpopnd1 = next->getOpnd(cmpuses.begin()); Opnd* cmpopnd2 = next->getOpnd(cmpuses.next(cmpuses.begin())); if (isImm(movopnd2) && (movopnd2->getImmValue() == 0 || movopnd2->getImmValue() == 1) && movopnd1->getId() == cmpopnd1->getId() && isImm(cmpopnd2) && cmpopnd2->getImmValue() == 0) { BitSet ls(irManager->getMemoryManager(), irManager->getOpndCount()); irManager->updateLivenessInfo(); irManager->getLiveAtExit(jump->getNode(), ls); bool opndNotUsed = !ls.getBit(movopnd1->getId()); if (opndNotUsed) { ControlFlowGraph* cfg = irManager->getFlowGraph(); Node* destination = ((BranchInst*)jump)->getTrueTarget(); if ((jump->getMnemonic() == Mnemonic_JNE || movopnd2->getImmValue() == 1) && !(jump->getMnemonic() == Mnemonic_JNE && movopnd2->getImmValue() == 1)) { destination = ((BranchInst*)jump)->getFalseTarget(); } if (node->getId() != next->getNode()->getId()) { if (methodMarkerOccur) { inst->getNode()->appendInst(irManager->newMethodEndPseudoInst(methodMarker->getMethodDesc())); } inst->unlink(); Edge *outEdge = node->getOutEdge(Edge::Kind_Unconditional); cfg->replaceEdgeTarget(outEdge, destination, true); cfg->purgeUnreachableNodes(); // previous successor may become unreachable } else { cfg->removeEdge(node->getOutEdge(Edge::Kind_True)); cfg->removeEdge(node->getOutEdge(Edge::Kind_False)); cfg->addEdge(node, destination); inst->unlink(); next->unlink(); jump->unlink(); } return Changed_Node; } } } } return Changed_Nothing; }