Index: lib/IR/ModuleSummaryIndex.cpp
===================================================================
--- lib/IR/ModuleSummaryIndex.cpp
+++ lib/IR/ModuleSummaryIndex.cpp
@@ -75,8 +75,8 @@
   auto InfoList = findGlobalValueInfoList(ValueGUID);
   assert(InfoList != end() && "GlobalValue not found in index");
   assert(!PerModuleIndex ||
-         InfoList->second.size() == 1 &&
-             "Expected a single entry per global value in per-module index");
+         (InfoList->second.size() == 1 &&
+          "Expected a single entry per global value in per-module index"));
   auto &Info = InfoList->second[0];
   return Info.get();
 }