diff --git a/poolalloc/include/dsa/DSCallGraph.h b/poolalloc/include/dsa/DSCallGraph.h
index b39a662..c9b1a8e 100644
--- a/poolalloc/include/dsa/DSCallGraph.h
+++ b/poolalloc/include/dsa/DSCallGraph.h
@@ -196,7 +196,7 @@
 
   void dump();
 
-  void assertSCCRoot(const llvm::Function* F) {
+  void assertSCCRoot(const llvm::Function* F) const {
     assert(F == SCCs.getLeaderValue(F) && "Not Leader?");
   }