diff --git a/lib/CodeGen/AsmPrinter/DebugLocEntry.h b/lib/CodeGen/AsmPrinter/DebugLocEntry.h
index 0834b36013d..7551c8f0ced 100644
--- a/lib/CodeGen/AsmPrinter/DebugLocEntry.h
+++ b/lib/CodeGen/AsmPrinter/DebugLocEntry.h
@@ -94,6 +94,9 @@ public:
     EntryKind = E_ConstantInt;
   }
 
+  /// \brief Attempt to merge this DebugLocEntry with Next and return
+  /// true if the merge was successful. Entries can be merged if they
+  /// share the same Loc/Constant and their ranges are adjacent.
   bool Merge(const DebugLocEntry &Next) {
     if (End == Next.Begin && hasSameValueOrLocation(Next)) {
       End = Next.End;