-// NewBB is split and now it has one successor. Update dominance frontier to
-// reflect this change.
-void DominanceFrontier::splitBlock(BasicBlock *NewBB) {
- assert(NewBB->getTerminator()->getNumSuccessors() == 1 &&
- "NewBB should have a single successor!");
- BasicBlock *NewBBSucc = NewBB->getTerminator()->getSuccessor(0);
-
- // NewBBSucc inherits original NewBB frontier.
- DominanceFrontier::iterator NewBBI = find(NewBB);
- if (NewBBI != end())
- addBasicBlock(NewBBSucc, NewBBI->second);
-
- // If NewBB dominates NewBBSucc, then DF(NewBB) is now going to be the
- // DF(NewBBSucc) without the stuff that the new block does not dominate
- // a predecessor of.
- DominatorTree &DT = getAnalysis<DominatorTree>();
- DomTreeNode *NewBBNode = DT.getNode(NewBB);
- DomTreeNode *NewBBSuccNode = DT.getNode(NewBBSucc);
- if (DT.dominates(NewBBNode, NewBBSuccNode)) {
- DominanceFrontier::iterator DFI = find(NewBBSucc);
- if (DFI != end()) {
- DominanceFrontier::DomSetType Set = DFI->second;
- // Filter out stuff in Set that we do not dominate a predecessor of.
- for (DominanceFrontier::DomSetType::iterator SetI = Set.begin(),
- E = Set.end(); SetI != E;) {
- bool DominatesPred = false;
- for (pred_iterator PI = pred_begin(*SetI), E = pred_end(*SetI);
- PI != E; ++PI)
- if (DT.dominates(NewBBNode, DT.getNode(*PI))) {
- DominatesPred = true;
- break;
- }
- if (!DominatesPred)
- Set.erase(SetI++);
- else
- ++SetI;
- }
-
- if (NewBBI != end()) {
- for (DominanceFrontier::DomSetType::iterator SetI = Set.begin(),
- E = Set.end(); SetI != E; ++SetI) {
- BasicBlock *SB = *SetI;
- addToFrontier(NewBBI, SB);
- }
- } else
- addBasicBlock(NewBB, Set);
- }
-
- } else {
- // DF(NewBB) is {NewBBSucc} because NewBB does not strictly dominate
- // NewBBSucc, but it does dominate itself (and there is an edge (NewBB ->
- // NewBBSucc)). NewBBSucc is the single successor of NewBB.
- DominanceFrontier::DomSetType NewDFSet;
- NewDFSet.insert(NewBBSucc);
- addBasicBlock(NewBB, NewDFSet);
- }
-
- // Now update dominance frontiers which either used to contain NewBBSucc
- // or which now need to include NewBB.
-
- // Collect the set of blocks which dominate a predecessor of NewBB or
- // NewSuccBB and which don't dominate both. This is an initial
- // approximation of the blocks whose dominance frontiers will need updates.
- SmallVector<DomTreeNode *, 16> AllPredDoms;
-
- // Compute the block which dominates both NewBBSucc and NewBB. This is
- // the immediate dominator of NewBBSucc unless NewBB dominates NewBBSucc.
- // The code below which climbs dominator trees will stop at this point,
- // because from this point up, dominance frontiers are unaffected.
- DomTreeNode *DominatesBoth = 0;
- if (NewBBSuccNode) {
- DominatesBoth = NewBBSuccNode->getIDom();
- if (DominatesBoth == NewBBNode)
- DominatesBoth = NewBBNode->getIDom();
- }
+bool DominatorTree::dominates(const BasicBlockEdge &BBE,
+ const BasicBlock *UseBB) const {
+ // Assert that we have a single edge. We could handle them by simply
+ // returning false, but since isSingleEdge is linear on the number of
+ // edges, the callers can normally handle them more efficiently.
+ assert(BBE.isSingleEdge());
+
+ // If the BB the edge ends in doesn't dominate the use BB, then the
+ // edge also doesn't.
+ const BasicBlock *Start = BBE.getStart();
+ const BasicBlock *End = BBE.getEnd();
+ if (!dominates(End, UseBB))
+ return false;