PR4317: Handle splits where the new block is unreachable correctly in
DominatorTreeBase::Split.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72810 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/Analysis/Dominators.h b/include/llvm/Analysis/Dominators.h
index b405f5b..347e239 100644
--- a/include/llvm/Analysis/Dominators.h
+++ b/include/llvm/Analysis/Dominators.h
@@ -270,12 +270,17 @@
NewBBIDom = PredBlocks[i];
break;
}
- assert(i != PredBlocks.size() && "No reachable preds?");
+
+ // It's possible that none of the predecessors of NewBB are reachable;
+ // in that case, NewBB itself is unreachable, so nothing needs to be
+ // changed.
+ if (!NewBBIDom)
+ return;
+
for (i = i + 1; i < PredBlocks.size(); ++i) {
if (DT.isReachableFromEntry(PredBlocks[i]))
NewBBIDom = DT.findNearestCommonDominator(NewBBIDom, PredBlocks[i]);
}
- assert(NewBBIDom && "No immediate dominator found??");
// Create the new dominator tree node... and set the idom of NewBB.
DomTreeNodeBase<NodeT> *NewBBNode = DT.addNewBlock(NewBB, NewBBIDom);
diff --git a/test/CodeGen/Generic/2009-06-03-UnreachableSplitPad.ll b/test/CodeGen/Generic/2009-06-03-UnreachableSplitPad.ll
new file mode 100644
index 0000000..59e7d0c
--- /dev/null
+++ b/test/CodeGen/Generic/2009-06-03-UnreachableSplitPad.ll
@@ -0,0 +1,15 @@
+; RUN: llvm-as < %s | llc
+; PR4317
+
+declare i32 @b()
+
+define void @a() {
+entry:
+ ret void
+
+dummy:
+ invoke i32 @b() to label %reg unwind label %reg
+
+reg:
+ ret void
+}