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 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);
}
}
}
