[PATCH 3/6] aarch64 doc: Fix description of .unreq directive.

[Alice Carlotti]

diff --git a/gas/doc/c-aarch64.texi b/gas/doc/c-aarch64.texi
index 0620ad8f4d216f99355ab50f1da63ca21db5c5b7..748ea7459e04ee2fe6dd067ae2e8c9702efa88d8 100644
--- a/gas/doc/c-aarch64.texi
+++ b/gas/doc/c-aarch64.texi
@@ -694,9 +694,10 @@ This undefines a register alias which was previously defined using the
         .unreq foo
 @end smallexample
 
-An error occurs if the name is undefined.  Note - this pseudo op can
-be used to delete builtin in register name aliases (eg 'w0').  This
-should only be done if it is really necessary.
+An error occurs if the name was not defined.  This directive can be used to
+undefine the built-in register aliases @code{ip0}, @code{ip1}, @code{lr} and
+@code{fp}, but this should only be done if it is really necessary.  Other
+built-in register names cannot be undefined.
 
 @c VVVVVVVVVVVVVVVVVVVVVVVVVV