1 files changed, 7 insertions, 0 deletions
diff --git a/include/llvm/ADT/MapVector.h b/include/llvm/ADT/MapVector.h
index 26a555ee1d3..3d78f4b203c 100644
--- a/include/llvm/ADT/MapVector.h
+++ b/include/llvm/ADT/MapVector.h
@@ -56,6 +56,13 @@ public:
 
   size_type size() const { return Vector.size(); }
 
+  /// Grow the MapVector so that it can contain at least \p NumEntries items
+  /// before resizing again.
+  void reserve(size_type NumEntries) {
+    Map.reserve(NumEntries);
+    Vector.reserve(NumEntries);
+  }
+
   iterator begin() { return Vector.begin(); }
   const_iterator begin() const { return Vector.begin(); }
   iterator end() { return Vector.end(); }