- // Scan the predecessors of BB, checking to see if BB dominates any of
- // them. This identifies backedges which target this node...
- typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
- for (typename InvBlockTraits::ChildIteratorType I =
- InvBlockTraits::child_begin(BB), E = InvBlockTraits::child_end(BB);
- I != E; ++I)
- if (DT.dominates(BB, *I)) // If BB dominates it's predecessor...
- TodoStack.push_back(*I);
-
- if (TodoStack.empty()) return 0; // No backedges to this block...
-
- // Create a new loop to represent this basic block...
- LoopT *L = new LoopT(BB);
- BBMap[BB] = L;
-
- BlockT *EntryBlock = BB->getParent()->begin();
-
- while (!TodoStack.empty()) { // Process all the nodes in the loop
- BlockT *X = TodoStack.back();
- TodoStack.pop_back();
-
- if (!L->contains(X) && // As of yet unprocessed??
- DT.dominates(EntryBlock, X)) { // X is reachable from entry block?
- // Check to see if this block already belongs to a loop. If this occurs
- // then we have a case where a loop that is supposed to be a child of
- // the current loop was processed before the current loop. When this
- // occurs, this child loop gets added to a part of the current loop,
- // making it a sibling to the current loop. We have to reparent this
- // loop.
- if (LoopT *SubLoop =
- const_cast<LoopT *>(getLoopFor(X)))
- if (SubLoop->getHeader() == X && isNotAlreadyContainedIn(SubLoop, L)){
- // Remove the subloop from it's current parent...
- assert(SubLoop->ParentLoop && SubLoop->ParentLoop != L);
- LoopT *SLP = SubLoop->ParentLoop; // SubLoopParent
- typename std::vector<LoopT *>::iterator I =
- std::find(SLP->SubLoops.begin(), SLP->SubLoops.end(), SubLoop);
- assert(I != SLP->SubLoops.end() &&"SubLoop not a child of parent?");
- SLP->SubLoops.erase(I); // Remove from parent...
-
- // Add the subloop to THIS loop...
- SubLoop->ParentLoop = L;
- L->SubLoops.push_back(SubLoop);
- }
-
- // Normal case, add the block to our loop...
- L->Blocks.push_back(X);
-
- typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
-
- // Add all of the predecessors of X to the end of the work stack...
- TodoStack.insert(TodoStack.end(), InvBlockTraits::child_begin(X),
- InvBlockTraits::child_end(X));
- }
- }
-
- // If there are any loops nested within this loop, create them now!
- for (typename std::vector<BlockT*>::iterator I = L->Blocks.begin(),
- E = L->Blocks.end(); I != E; ++I)
- if (LoopT *NewLoop = ConsiderForLoop(*I, DT)) {
- L->SubLoops.push_back(NewLoop);
- NewLoop->ParentLoop = L;
- }
-
- // Add the basic blocks that comprise this loop to the BBMap so that this
- // loop can be found for them.
- //
- for (typename std::vector<BlockT*>::iterator I = L->Blocks.begin(),
- E = L->Blocks.end(); I != E; ++I) {
- typename std::map<BlockT*, LoopT *>::iterator BBMI = BBMap.find(*I);
- if (BBMI == BBMap.end()) // Not in map yet...
- BBMap.insert(BBMI, std::make_pair(*I, L)); // Must be at this level
- }