If NewBB dominates DestBB then DestBB is not part of NewBB's dominance frontier.

llvm-svn: 41051

1 files changed, 5 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp b/llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp
index af9a114bbeb..e28d59d7c3a 100644
--- a/llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp
+++ b/llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp
@@ -227,8 +227,12 @@ bool llvm::SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, Pass *P,
     DominanceFrontier::DomSetType NewDFSet;
     if (NewBBDominatesDestBB) {
       DominanceFrontier::iterator I = DF->find(DestBB);
-      if (I != DF->end())
+      if (I != DF->end()) {
         DF->addBasicBlock(NewBB, I->second);
+        // However NewBB's frontier does not include DestBB.
+        DominanceFrontier::iterator NF = DF->find(NewBB);
+        DF->removeFromFrontier(NF, DestBB);
+      }
       else
         DF->addBasicBlock(NewBB, DominanceFrontier::DomSetType());
     } else {