diff --git a/lib/Support/SmallPtrSet.cpp b/lib/Support/SmallPtrSet.cpp
index 0e6d3345905..48552a56fc4 100644
--- a/lib/Support/SmallPtrSet.cpp
+++ b/lib/Support/SmallPtrSet.cpp
@@ -7,7 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// This file implements the SmallPtrSet class.
+// This file implements the SmallPtrSet class.  See SmallPtrSet.h for an
+// overview of the algorithm.
 //
 //===----------------------------------------------------------------------===//