diff --git a/gcc/doc/implement-c.texi b/gcc/doc/implement-c.texi
index 692297b69c4..d7433ba5213 100644
--- a/gcc/doc/implement-c.texi
+++ b/gcc/doc/implement-c.texi
@@ -576,6 +576,11 @@ are of scalar types, the expression is interpreted by GCC as a read of
 the volatile object; in the other cases, the expression is only evaluated
 for its side effects.
 
+When an object of an aggregate type, with the same size and alignment as a
+scalar type @code{S}, is the subject of a volatile access by an assignment
+expression or an atomic function, the access to it is performed as if the
+object's declared type were @code{volatile S}.
+
 @end itemize
 
 @node Declarators implementation