diff --git a/COFF/Driver.cpp b/COFF/Driver.cpp
index 19c8702..45befa6 100644
--- a/COFF/Driver.cpp
+++ b/COFF/Driver.cpp
@@ -81,6 +81,7 @@
   ObjFile::Instances.clear();
   ImportFile::Instances.clear();
   BitcodeFile::Instances.clear();
+  memset(MergeChunk::Instances, 0, sizeof(MergeChunk::Instances));
   return !errorCount();
 }