diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 33ce266dc22..6fa28433fc1 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2013-08-30  Mike Stump  <mikestump@comcast.net>
+
+	* doc/install.texi (Prerequisites): Note regression in Tcl 8.6
+	with RE patterns.
+
 2013-08-29  Jan Hubicka  <jh@suse.cz>
 
 	* cgraph.c (cgraph_function_body_availability): Handle weakref
diff --git a/gcc/doc/install.texi b/gcc/doc/install.texi
index 9e5ba5e66c0..221e60e952c 100644
--- a/gcc/doc/install.texi
+++ b/gcc/doc/install.texi
@@ -426,7 +426,11 @@ Necessary when modifying @command{gperf} input files, e.g.@:
 @itemx Expect
 @itemx Tcl
 
-Necessary to run the GCC testsuite; see the section on testing for details.
+Necessary to run the GCC testsuite; see the section on testing for
+details.  Tcl 8.6 has a known regression in RE pattern handling that
+make parts of the testsuite fail.  See
+@uref{http://core.tcl.tk/tcl/tktview/267b7e2334ee2e9de34c4b00d6e72e2f1997085f}
+for more information.
 
 @item autogen version 5.5.4 (or later) and
 @itemx guile version 1.4.1 (or later)