diff --git a/clang/docs/UsersManual.rst b/clang/docs/UsersManual.rst
index 438ef46a45e0..6d321952cf8a 100644
--- a/clang/docs/UsersManual.rst
+++ b/clang/docs/UsersManual.rst
@@ -1856,6 +1856,12 @@ best-effort basis. For example, information regarding indirect call targets is
 currently not remapped. For best results, you are encouraged to generate new
 profile data matching the updated program.
 
+.. note::
+
+  Profile data remapping support is currently only implemented for LLVM's
+  new pass manager, which can be enabled with
+  ``-fexperimental-new-pass-manager``.
+
 .. note::
 
   Profile data remapping is currently only supported for C++ mangled names