[patch] implement generic debug() functions for wide_int's

[Aldy Hernandez <aldyh at redhat dot com>]

It looks like the generic debug() function for wide_int's is missing.
Instead, we have a wi->dump() method.  I have implemented debug() for
generic wide_int and for widest_int, which should cover the common
cases.  Anything else, can continue using the ->dump() method
templated methods.

Also, do we have a blessed way of specifying overloaded functions in
ChangeLog's?  I couldn't find anything in our GCC coding guidelines or
in the GNU coding guidelines.  For lack of direction, I'm doing the
following:

* wide-int.cc (debug) [const wide_int &]: New.
(debug) [const wide_int *]: New.
(debug) [const widest_int &]: New.
(debug) [const widest_int *]: New.

It seems appropriate, as that is the GNU way of changelogs for a
conditional change to a function ???.

OK for trunk?

gcc/

	* wide-int.cc (debug) [const wide_int &]: New.
	(debug) [const wide_int *]: New.
	(debug) [const widest_int &]: New.
	(debug) [const widest_int *]: New.

diff --git a/gcc/wide-int.cc b/gcc/wide-int.cc
index 71e24ec22af..1a1a68c1943 100644
--- a/gcc/wide-int.cc
+++ b/gcc/wide-int.cc
@@ -2146,6 +2146,39 @@ template void generic_wide_int <wide_int_ref_storage <true> >::dump () const;
 template void offset_int::dump () const;
 template void widest_int::dump () const;
 
+/* We could add all the above ::dump variants here, but wide_int and
+   widest_int should handle the common cases.  Besides, you can always
+   call the dump method directly.  */
+
+DEBUG_FUNCTION void
+debug (const wide_int &ref)
+{
+  ref.dump ();
+}
+
+DEBUG_FUNCTION void
+debug (const wide_int *ptr)
+{
+  if (ptr)
+    debug (*ptr);
+  else
+    fprintf (stderr, "<nil>\n");
+}
+
+DEBUG_FUNCTION void
+debug (const widest_int &ref)
+{
+  ref.dump ();
+}
+
+DEBUG_FUNCTION void
+debug (const widest_int *ptr)
+{
+  if (ptr)
+    debug (*ptr);
+  else
+    fprintf (stderr, "<nil>\n");
+}
 
 #if CHECKING_P