+ typedef std::iterator_traits<LiveStacks::iterator>::value_type Pair;
+ SmallVector<Pair *, 16> Intervals;
+ Intervals.reserve(LS->getNumIntervals());
+ for (auto &I : *LS)
+ Intervals.push_back(&I);
+ std::sort(Intervals.begin(), Intervals.end(),
+ [](Pair *LHS, Pair *RHS) { return LHS->first < RHS->first; });
+