// If main trace ends with an unconditional jump, and the target is not
// reached by any other branch, then copy the target of the jump to the
// end of the trace
static void elimUnconditionalJump(Trace* trace, IRFactory* irFactory) {
boost::dynamic_bitset<> isJoin(irFactory->numLabels());
boost::dynamic_bitset<> havePred(irFactory->numLabels());
IRInstruction::List& instList = trace->getInstructionList();
for (IRInstruction* inst : instList) {
if (inst->isControlFlowInstruction()) {
auto id = inst->getLabel()->getLabelId();
isJoin[id] = havePred[id];
havePred[id] = 1;
}
}
IRInstruction::Iterator lastInst = instList.end();
--lastInst; // go back to the last instruction
IRInstruction* jmp = *lastInst;
if (jmp->getOpcode() == Jmp_ && !isJoin[jmp->getLabel()->getLabelId()]) {
Trace* targetTrace = jmp->getLabel()->getParent();
IRInstruction::List& targetInstList = targetTrace->getInstructionList();
IRInstruction::Iterator instIter = targetInstList.begin();
instIter++; // skip over label
// update the parent trace of the moved instructions
for (IRInstruction::Iterator it = instIter;
it != targetInstList.end();
++it) {
(*it)->setParent(trace);
}
instList.splice(lastInst, targetInstList, instIter, targetInstList.end());
// delete the jump instruction
instList.erase(lastInst);
}
}
void Lanes::afterMerge() {
if (boundary)
return; // will be reset by changeActiveLane()
for (unsigned int i = 0; i < typeVec.size(); ++i) {
int& t = typeVec[i];
if (isHead(t) || isJoin(t) || t == CROSS)
t = NOT_ACTIVE;
else if (t == CROSS_EMPTY)
t = EMPTY;
else if (IS_NODE(t))
t = ACTIVE;
}
}
// If main trace ends with an unconditional jump, and the target is not
// reached by any other branch, then copy the target of the jump to the
// end of the trace
static void elimUnconditionalJump(Trace* trace, IRFactory* irFactory) {
boost::dynamic_bitset<> isJoin(irFactory->numBlocks());
boost::dynamic_bitset<> havePred(irFactory->numBlocks());
for (Block* block : trace->getBlocks()) {
if (block->getTaken()) {
auto id = block->getTaken()->getId();
isJoin[id] = havePred[id];
havePred[id] = 1;
}
if (block->getNext()) {
auto id = block->getNext()->getId();
isJoin[id] = havePred[id];
havePred[id] = 1;
}
}
Block* lastBlock = trace->back();
auto lastInst = lastBlock->backIter(); // iterator to last instruction
IRInstruction& jmp = *lastInst;
if (jmp.getOpcode() == Jmp_ && !isJoin[jmp.getTaken()->getId()]) {
Block* target = jmp.getTaken();
lastBlock->splice(lastInst, target, target->skipLabel(), target->end());
lastBlock->erase(lastInst); // delete the jmp
}
}
