diff --git a/lib/StaticAnalyzer/Core/BugReporter.cpp b/lib/StaticAnalyzer/Core/BugReporter.cpp
index 1eaf1f9..7ba2fa7 100644
--- a/lib/StaticAnalyzer/Core/BugReporter.cpp
+++ b/lib/StaticAnalyzer/Core/BugReporter.cpp
@@ -1536,6 +1536,8 @@
          I = bugTypes.begin(), E = bugTypes.end(); I != E; ++I)
     const_cast<BugType*>(*I)->FlushReports(*this);
 
+  // We need to flush reports in deterministic order to ensure the order
+  // of the reports is consistent between runs.
   typedef std::vector<BugReportEquivClass *> ContVecTy;
   for (ContVecTy::iterator EI=EQClassesVector.begin(), EE=EQClassesVector.end();
        EI != EE; ++EI){