When identifying exit nodes for the reverse-CFG reverse-post-order
traversal, consider nodes for which the only successors are backedges
which the traversal is ignoring to be exit nodes. This fixes a problem
where the bottom-up traversal was failing to visit split blocks along
split loop backedges. This fixes rdar://10989035.
llvm-svn: 152421
diff --git a/llvm/lib/Transforms/Scalar/ObjCARC.cpp b/llvm/lib/Transforms/Scalar/ObjCARC.cpp
index 1c7f036..91dc23c 100644
--- a/llvm/lib/Transforms/Scalar/ObjCARC.cpp
+++ b/llvm/lib/Transforms/Scalar/ObjCARC.cpp
@@ -2929,11 +2929,17 @@
Visited.clear();
// Compute the exits, which are the starting points for reverse-CFG DFS.
+ // This includes blocks where all the successors are backedges that
+ // we're skipping.
SmallVector<BasicBlock *, 4> Exits;
for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) {
BasicBlock *BB = I;
- if (cast<TerminatorInst>(&BB->back())->getNumSuccessors() == 0)
- Exits.push_back(BB);
+ TerminatorInst *TI = cast<TerminatorInst>(&BB->back());
+ for (succ_iterator SI(TI), SE(TI, true); SI != SE; ++SI)
+ if (!Backedges.count(std::make_pair(BB, *SI)))
+ goto HasNonBackedgeSucc;
+ Exits.push_back(BB);
+ HasNonBackedgeSucc:;
}
// Do reverse-CFG DFS, computing the reverse-CFG PostOrder.