diff --git a/llvm/lib/Bytecode/Reader/Reader.cpp b/llvm/lib/Bytecode/Reader/Reader.cpp
index e08656822d..a5e70d9 100644
--- a/llvm/lib/Bytecode/Reader/Reader.cpp
+++ b/llvm/lib/Bytecode/Reader/Reader.cpp
@@ -2166,6 +2166,7 @@
                                    const std::string &ModuleID) {
 
   try {
+    RevisionNum = 0;
     At = MemStart = BlockStart = Buf;
     MemEnd = BlockEnd = Buf + Length;