diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog
index 10a9ddd86eaeb05369ad1d40e356642a2fa8ddea..2746d04fe4af918fd4a7a4139b53b63736615bc6 100644
--- a/gcc/c-family/ChangeLog
+++ b/gcc/c-family/ChangeLog
@@ -1,3 +1,9 @@
+2012-01-17  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/51777
+	* c-pretty-print.c (pp_c_integer_constant): For unsigned constants
+	use pp_unsigned_wide_integer.
+
 2012-01-10  Richard Guenther  <rguenther@suse.de>
 
 	PR middle-end/51806
diff --git a/gcc/c-family/c-pretty-print.c b/gcc/c-family/c-pretty-print.c
index be28b39e6a343081c29194cc36cb55f7ed77a53f..dc63f0048de43084c1732a70866116e72b51f609 100644
--- a/gcc/c-family/c-pretty-print.c
+++ b/gcc/c-family/c-pretty-print.c
@@ -910,8 +910,10 @@ pp_c_integer_constant (c_pretty_printer *pp, tree i)
     ? TYPE_CANONICAL (TREE_TYPE (i))
     : TREE_TYPE (i);
 
-  if (TREE_INT_CST_HIGH (i) == 0)
+  if (host_integerp (i, 0))
     pp_wide_integer (pp, TREE_INT_CST_LOW (i));
+  else if (host_integerp (i, 1))
+    pp_unsigned_wide_integer (pp, TREE_INT_CST_LOW (i));
   else
     {
       unsigned HOST_WIDE_INT low = TREE_INT_CST_LOW (i);