// These dominator edges will be redirected from Pred.
std::vector<DominatorTree::UpdateType> Updates;
if (DTU) {
- Updates.reserve(1 + (2 * succ_size(BB)));
+ SmallSetVector<BasicBlock *, 2> UniqueSuccessors(succ_begin(BB),
+ succ_end(BB));
+ Updates.reserve(1 + (2 * UniqueSuccessors.size()));
// Add insert edges first. Experimentally, for the particular case of two
// blocks that can be merged, with a single successor and single predecessor
// respectively, it is beneficial to have all insert updates first. Deleting
// edges first may lead to unreachable blocks, followed by inserting edges
// making the blocks reachable again. Such DT updates lead to high compile
// times. We add inserts before deletes here to reduce compile time.
- for (auto I = succ_begin(BB), E = succ_end(BB); I != E; ++I)
+ for (BasicBlock *UniqueSuccessor : UniqueSuccessors)
// This successor of BB may already have PredBB as a predecessor.
- if (!llvm::is_contained(successors(PredBB), *I))
- Updates.push_back({DominatorTree::Insert, PredBB, *I});
- for (auto I = succ_begin(BB), E = succ_end(BB); I != E; ++I)
- Updates.push_back({DominatorTree::Delete, BB, *I});
+ if (!llvm::is_contained(successors(PredBB), UniqueSuccessor))
+ Updates.push_back({DominatorTree::Insert, PredBB, UniqueSuccessor});
+ for (BasicBlock *UniqueSuccessor : UniqueSuccessors)
+ Updates.push_back({DominatorTree::Delete, BB, UniqueSuccessor});
Updates.push_back({DominatorTree::Delete, PredBB, BB});
}
isa<UnreachableInst>(BB->getTerminator()) &&
"The successor list of BB isn't empty before "
"applying corresponding DTU updates.");
- DTU->applyUpdatesPermissive(Updates);
+ DTU->applyUpdates(Updates);
DTU->deleteBB(BB);
} else {
BB->eraseFromParent(); // Nuke BB if DTU is nullptr.