diff --git a/lib/CodeGen/LiveVariables.cpp b/lib/CodeGen/LiveVariables.cpp
index bb72d80..2034566 100644
--- a/lib/CodeGen/LiveVariables.cpp
+++ b/lib/CodeGen/LiveVariables.cpp
@@ -48,6 +48,7 @@
 void LiveVariables::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.addRequiredID(UnreachableMachineBlockElimID);
   AU.setPreservesAll();
+  MachineFunctionPass::getAnalysisUsage(AU);
 }
 
 void LiveVariables::VarInfo::dump() const {