Index: lib/CodeGen/MachineBlockPlacement.cpp
===================================================================
--- lib/CodeGen/MachineBlockPlacement.cpp
+++ lib/CodeGen/MachineBlockPlacement.cpp
@@ -1599,6 +1599,7 @@
   collectMustExecuteBBs();
 
   // Build any loop-based chains.
+  PreferredLoopExit = nullptr;
   for (MachineLoop *L : *MLI)
     buildLoopChains(*L);