diff --git a/llvm/lib/Analysis/CodeMetrics.cpp b/llvm/lib/Analysis/CodeMetrics.cpp
index 97d0463..f3b34bf 100644
--- a/llvm/lib/Analysis/CodeMetrics.cpp
+++ b/llvm/lib/Analysis/CodeMetrics.cpp
@@ -37,7 +37,9 @@
   // alive only by ephemeral values.
 
   while (!WorkSet.empty()) {
-    const Value *V = WorkSet.pop_back_val();
+    const Value *V = WorkSet.front();
+    WorkSet.erase(WorkSet.begin());
+
     if (!Visited.insert(V))
       continue;