diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index cf6a8504c135..0f97b43b5170 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2006-07-12  Paolo Carlini  <pcarlini@suse.de>
+
+	PR libstdc++/27878
+	* doc/install.texi (mips-sgi-irix6): Add note about IRIX 6.5.x,
+	x < 19, vs wchar_t support.
+
 2006-07-12  Nick Clifton  <nickc@redhat.com>
 
 	* config/sh/sh.h (SUBTARGET_ASM_RELAX_SPEC): Use -isa=sh4-up
diff --git a/gcc/doc/install.texi b/gcc/doc/install.texi
index 09922d59ab5e..658c07287b81 100644
--- a/gcc/doc/install.texi
+++ b/gcc/doc/install.texi
@@ -3565,6 +3565,11 @@ to build despite this, running into an internal error of the native
 its maximum of 262144 bytes.  If you have root access, you can use the
 @command{systune} command to do this.
 
+@code{wchar_t} support in @samp{libstdc++} is not available for old
+IRIX 6.5.x releases, @math{x < 19}.  The problem cannot be autodetected
+and in order to build GCC for such targets you need to configure with
+@option{--disable-wchar_t}.
+
 See @uref{http://freeware.sgi.com/} for more
 information about using GCC on IRIX platforms.