void SSABuilder::clearPhiSrcs(Node *node, const StlVectorSet<VarOpnd *> *whatVars) { Inst* phi = (Inst*)node->getSecondInst(); if (whatVars) { for (;phi!=NULL && phi->isPhi(); phi = phi->getNextInst()) { Opnd *dstOp = phi->getDst(); VarOpnd *varOpnd = dstOp->asVarOpnd(); if (!varOpnd) { SsaVarOpnd *ssaOpnd = dstOp->asSsaVarOpnd(); assert(ssaOpnd); varOpnd = ssaOpnd->getVar(); } if (whatVars->has(varOpnd)) { PhiInst *phiInst = phi->asPhiInst(); assert(phiInst); phiInst->setNumSrcs(0); } } } else { for (;phi!=NULL && phi->isPhi(); phi = phi->getNextInst()) { PhiInst *phiInst = phi->asPhiInst(); assert(phiInst); phiInst->setNumSrcs(0); } } }
void SSABuilder::checkForTrivialPhis2(Node *node, const StlVectorSet<VarOpnd *> *lookatVars, StlVector<VarOpnd *> *changedVars, StlVector<Opnd *> *removedVars) { // Check that phi insts can start from the second or third position only // and goes in a row assert(phiInstsOnRightPositionsInBB(node)); Inst* phi = (Inst*)node->getSecondInst(); if(phi && !phi->isPhi()) { // try the next one (third) phi = phi->getNextInst(); } Inst *nextphi = NULL; #ifdef DEBUG_SSA if (Log::isEnabled()) { Log::out() << "Checking node " << (int)node->getId() << " for trivial phis2" << ::std::endl; } #endif for (;phi->isPhi(); phi = nextphi) { nextphi = phi->getNextInst(); #ifdef _DEBUG PhiInst *phiInst = phi->asPhiInst(); assert(phiInst); #endif U_32 nSrcs = phi->getNumSrcOperands(); if (nSrcs <= 1) { // phi must be trivial #ifdef DEBUG_SSA ::std::ostream &cout = Log::out(); if (Log::isEnabled()) { cout << "removing trivial2 instruction "; phi->print(cout); cout << ::std::endl; } #endif Opnd *dstOp = phi->getDst(); VarOpnd *varOp = dstOp->asVarOpnd(); if (!varOp) { SsaVarOpnd *ssaOp = dstOp->asSsaVarOpnd(); assert(ssaOp); varOp = ssaOp->getVar(); } assert(!lookatVars || (lookatVars->has(varOp))); changedVars->push_back(varOp); removedVars->push_back(dstOp); phi->unlink(); } } }
void applyToInst(Inst *inst) { if (inst->getOpcode() == Op_Phi) { // we should just delete the whole thing. Opnd *dstOpnd = inst->getDst(); if (dstOpnd->isSsaVarOpnd()) { SsaVarOpnd *ssaOpnd = dstOpnd->asSsaVarOpnd(); VarOpnd *var = ssaOpnd->getVar(); if (usedOutOfSsa.has(var)) { // remove instruction inst->unlink(); return; } } else if (dstOpnd->isVarOpnd()) { VarOpnd *var = dstOpnd->asVarOpnd(); if (usedOutOfSsa.has(var)) { // remove instruction inst->unlink(); return; } } } U_32 numSrcs = inst->getNumSrcOperands(); for (U_32 i=0; i<numSrcs; ++i) { Opnd *thisOpnd = inst->getSrc(i); VarOpnd *varOpnd = needToDeSsaOpnd(thisOpnd); if (varOpnd) { inst->setSrc(i, varOpnd); } } Opnd *dstOpnd = inst->getDst(); VarOpnd *varDstOpnd = needToDeSsaOpnd(dstOpnd); if (varDstOpnd) { inst->setDst(varDstOpnd); } }
void SSABuilder::clearPhiSrcs2(Node *node, const StlVectorSet<VarOpnd *> *whatVars, StlVector<VarOpnd *> *changedVars, const StlVectorSet<Opnd *> *removedVars, StlVector<Node *> &scratchNodeList) { bool needPreds = true; StlVector<Node *> &preds = scratchNodeList; Inst* inst = (Inst*)node->getSecondInst(); for (;inst!=NULL && inst->isPhi(); inst = inst->getNextInst()) { Opnd *dstOp =inst->getDst(); VarOpnd *varOpnd = 0; if (whatVars) { varOpnd = dstOp->asVarOpnd(); if (!varOpnd) { SsaVarOpnd *ssaOpnd = dstOp->asSsaVarOpnd(); assert(ssaOpnd); varOpnd = ssaOpnd->getVar(); } if (!whatVars->has(varOpnd)) continue; } bool changed=false; U_32 numSrcs = inst->getNumSrcOperands(); for (U_32 i=0; i<numSrcs; ++i) { Opnd *thisOpnd = inst->getSrc(i); if (!(removedVars && removedVars->has(thisOpnd))) { // need to test whether need to remove if (needPreds) { needPreds = false; const Edges& edges2 = node->getInEdges(); preds.clear(); preds.reserve(edges2.size()); Edges::const_iterator eiter2; for(eiter2 = edges2.begin(); eiter2 != edges2.end(); ++eiter2){ preds.push_back((*eiter2)->getSourceNode()); } } DominatorTree &domTree = frontier.getDominator(); Inst *thisOpndInst = thisOpnd->getInst(); Node *thisOpndInstNode = thisOpndInst->getNode(); if (thisOpndInstNode) { // the operand's source instruction was not already dead. StlVector<Node *>::const_iterator predIter = preds.begin(), predEnd = preds.end(); bool foundDom = false; for ( ; predIter != predEnd; ++predIter) { Node *predNode = *predIter; if (domTree.dominates(thisOpndInstNode, predNode)) { // we found it, leave this operand alone. foundDom = true; break; } } if (foundDom) continue; // leave operand alone. } } // remove this operand; if (i < numSrcs-1) { inst->setSrc(i, inst->getSrc(numSrcs-1)); --i; // re-examine this operand, which is now the last } --numSrcs; // we deleted one operand PhiInst *phiInst = inst->asPhiInst(); assert(phiInst); phiInst->setNumSrcs(numSrcs); changed = true; } if (changed) { // note the changed var; if (!varOpnd) { varOpnd = dstOp->asVarOpnd(); if (!varOpnd) { SsaVarOpnd *ssaOpnd = dstOp->asSsaVarOpnd(); assert(ssaOpnd); varOpnd = ssaOpnd->getVar(); } } changedVars->push_back(varOpnd); } } }
// // traverse dominator tree and rename variables // void SSABuilder::renameNode(RenameStack *renameStack, DominatorNode* dt, const StlVectorSet<VarOpnd *> *whatVars) { if (dt == NULL) return; Node* node = dt->getNode(); Inst* head = (Inst*)node->getFirstInst(); #ifdef DEBUG_SSA std::ostream &cout = Log::out(); if (Log::isEnabled()) { cout << "renameNode "; FlowGraph::printLabel(cout, node); cout << std::endl; } #endif for (Inst* i = head->getNextInst(); i != NULL; i = i->getNextInst()) { if (!i->isPhi()) { // replace src with ssa opnd U_32 nSrcs = i->getNumSrcOperands(); for (U_32 j = 0; j < nSrcs; j++) { Opnd *srcj = i->getSrc(j); VarOpnd *srcjVar = (srcj->isSsaVarOpnd() ? srcj->asSsaVarOpnd()->getVar() : srcj->asVarOpnd()); if (!(srcjVar && !srcjVar->isAddrTaken())) continue; if (whatVars && !whatVars->has(srcjVar)) continue; SsaVarOpnd* ssa = renameStack->lookup(srcjVar); assert(ssa); i->setSrc(j,ssa); } } // for both Phi and non-Phi // we replace any non-ssa dst with a new ssa opnd // and record it in the RenameStack map Opnd* dst = i->getDst(); VarOpnd *theVar = dst->asVarOpnd(); if (theVar && (!theVar->isAddrTaken()) && !(whatVars && !whatVars->has(theVar))) { SsaVarOpnd* ssaDst = opndManager.createSsaVarOpnd((VarOpnd*)dst); #ifdef DEBUG_SSA if (Log::isEnabled()) { cout << "SSA "; ssaDst->print(cout); cout << ::std::endl; } #endif renameStack->insert((VarOpnd*)dst, ssaDst); i->setDst(ssaDst); #ifdef DEBUG_SSA if (Log::isEnabled()) { i->print(cout); cout << ::std::endl; } #endif // record stVar inst } else if (dst->isSsaVarOpnd()) { SsaVarOpnd* ssaDst = dst->asSsaVarOpnd(); theVar = ssaDst->getVar(); if (whatVars && !whatVars->has(theVar)) continue; #ifdef DEBUG_SSA if (Log::isEnabled()) { cout << "SSA "; ssaDst->print(cout); cout << ::std::endl; } #endif renameStack->insert(ssaDst->getVar(), ssaDst); #ifdef DEBUG_SSA if (Log::isEnabled()) { i->print(cout); cout << ::std::endl; } #endif } } // add var sources to following phi instructions const Edges& edges = node->getOutEdges(); Edges::const_iterator eiter = edges.begin(), eend = edges.end(); for(eiter = edges.begin(); eiter != eend; ++eiter) { Edge* e = *eiter; Node* succ = e->getTargetNode(); // Phi insts are inserted to the beginning of the block // if succ does not have phi insts, then we can skip it Inst *phi = (Inst*)succ->getSecondInst(); if (phi==NULL || !phi->isPhi()) continue; // node is jth predecessor for succ // replace jth var of phi insts Inst* nextphi = phi->getNextInst(); for (;phi!=NULL && phi->isPhi(); phi = nextphi) { nextphi = phi->getNextInst(); // get var Opnd *theopnd = phi->getDst(); VarOpnd *thevar = theopnd->asVarOpnd(); if (!thevar) { SsaVarOpnd *theSsaVar = theopnd->asSsaVarOpnd(); assert(theSsaVar); #ifdef DEBUG_SSA if (Log::isEnabled()) { Log::out() << "case 2" << ::std::endl; } #endif thevar = theSsaVar->getVar(); } if (whatVars && !whatVars->has(thevar)) continue; SsaVarOpnd* ssa = renameStack->lookup((VarOpnd*)thevar); if (ssa != NULL) { #ifdef DEBUG_SSA if (Log::isEnabled()) { cout << "redge"; // cout << (I_32)j; cout << " with ssa "; ssa->print(cout); cout << ::std::endl; } #endif addPhiSrc((PhiInst*)phi,ssa); } else { #ifdef DEBUG_SSA if (Log::isEnabled()) { cout << "no source for phi of var "; thevar->print(cout); cout << ::std::endl; } #endif // if ssa is NULL, then the phi must be a dead phi inst // (no more use of var afterwards). it will be removed. } } } }