Index: docs/ReleaseNotes.rst
===================================================================
--- docs/ReleaseNotes.rst
+++ docs/ReleaseNotes.rst
@@ -63,9 +63,18 @@
            indirect(a, n);
        }
 
-
 -  ...
 
+Improvements to ThinLTO (-flto=thin)
+------------------------------------
+  - Integration with profile data. When available, profile data enables more
+    accurate function importing decisions, as well as cross-module indirect call
+    promotion.
+  - Significant build-time and binary-size improvements when compiling with
+    debug info (-g).
+
+
+
 Improvements to Clang's diagnostics
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^