/// removeRange - Remove the specified range from this interval. Note that
/// the range must be in a single LiveRange in its entirety.
void LiveInterval::removeRange(SlotIndex Start, SlotIndex End,
bool RemoveDeadValNo) {
// Find the LiveRange containing this span.
Ranges::iterator I = std::upper_bound(ranges.begin(), ranges.end(), Start);
assert(I != ranges.begin() && "Range is not in interval!");
--I;
assert(I->containsRange(Start, End) && "Range is not entirely in interval!");
// If the span we are removing is at the start of the LiveRange, adjust it.
VNInfo *ValNo = I->valno;
if (I->start == Start) {
if (I->end == End) {
ValNo->removeKills(Start, End);
if (RemoveDeadValNo) {
// Check if val# is dead.
bool isDead = true;
for (const_iterator II = begin(), EE = end(); II != EE; ++II)
if (II != I && II->valno == ValNo) {
isDead = false;
break;
}
if (isDead) {
// Now that ValNo is dead, remove it. If it is the largest value
// number, just nuke it (and any other deleted values neighboring it),
// otherwise mark it as ~1U so it can be nuked later.
if (ValNo->id == getNumValNums()-1) {
do {
valnos.pop_back();
} while (!valnos.empty() && valnos.back()->isUnused());
} else {
ValNo->setIsUnused(true);
}
}
}
ranges.erase(I); // Removed the whole LiveRange.
} else
I->start = End;
return;
}
// Otherwise if the span we are removing is at the end of the LiveRange,
// adjust the other way.
if (I->end == End) {
ValNo->removeKills(Start, End);
I->end = Start;
return;
}
// Otherwise, we are splitting the LiveRange into two pieces.
SlotIndex OldEnd = I->end;
I->end = Start; // Trim the old interval.
// Insert the new one.
ranges.insert(next(I), LiveRange(End, OldEnd, ValNo));
}
/// extendIntervalEndTo - This method is used when we want to extend the range
/// specified by I to end at the specified endpoint. To do this, we should
/// merge and eliminate all ranges that this will overlap with. The iterator is
/// not invalidated.
void LiveInterval::extendIntervalEndTo(Ranges::iterator I, SlotIndex NewEnd) {
assert(I != ranges.end() && "Not a valid interval!");
VNInfo *ValNo = I->valno;
SlotIndex OldEnd = I->end;
// Search for the first interval that we can't merge with.
Ranges::iterator MergeTo = next(I);
for (; MergeTo != ranges.end() && NewEnd >= MergeTo->end; ++MergeTo) {
assert(MergeTo->valno == ValNo && "Cannot merge with differing values!");
}
// If NewEnd was in the middle of an interval, make sure to get its endpoint.
I->end = std::max(NewEnd, prior(MergeTo)->end);
// Erase any dead ranges.
ranges.erase(next(I), MergeTo);
// Update kill info.
ValNo->removeKills(OldEnd, I->end.getPrevSlot());
// If the newly formed range now touches the range after it and if they have
// the same value number, merge the two ranges into one range.
Ranges::iterator Next = next(I);
if (Next != ranges.end() && Next->start <= I->end && Next->valno == ValNo) {
I->end = Next->end;
ranges.erase(Next);
}
}