diff --git a/lib/Transforms/Scalar/LoopRotation.cpp b/lib/Transforms/Scalar/LoopRotation.cpp
index 2c76706bafa..f8122bf9803 100644
--- a/lib/Transforms/Scalar/LoopRotation.cpp
+++ b/lib/Transforms/Scalar/LoopRotation.cpp
@@ -418,6 +418,9 @@ bool LoopRotate::rotateLoop(Loop *L) {
       for (unsigned I = 0, E = HeaderChildren.size(); I != E; ++I)
         DT->changeImmediateDominator(HeaderChildren[I], OrigPreheaderNode);
 
+      assert(DT->getNode(Exit)->getIDom() == OrigPreheaderNode);
+      assert(DT->getNode(NewHeader)->getIDom() == OrigPreheaderNode);
+
       // Update OrigHeader to be dominated by the new header block.
       DT->changeImmediateDominator(OrigHeader, OrigLatch);
     }