Index: lib/Transforms/Scalar/LoopSimplifyCFG.cpp
===================================================================
--- lib/Transforms/Scalar/LoopSimplifyCFG.cpp
+++ lib/Transforms/Scalar/LoopSimplifyCFG.cpp
@@ -61,7 +61,12 @@
     // Merge Succ into Pred and delete it.
     MergeBlockIntoPredecessor(Succ, &DTU, &LI);
 
+    // Deleted block Succ was part of loop L and all its parent loops.
     SE.forgetLoop(&L);
+    auto *LoopForget = &L;
+    while ((LoopForget = LoopForget->getParentLoop()))
+      SE.forgetLoop(LoopForget);
+
     Changed = true;
   }