diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index a6617a21e2c..b97a1a44310 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,8 @@
+2002-03-12  Richard Sandiford  <rsandifo@redhat.com>
+
+	* mangle.c (write_builtin_type): Handle 128-bit integers even if
+	they are not a standard integer type.
+
 2002-03-12  Richard Sandiford  <rsandifo@redhat.com>
 
 	* cp-tree.h (init_init_processing): Remove declaration.
diff --git a/gcc/cp/mangle.c b/gcc/cp/mangle.c
index 360e1fc759d..239714d77d1 100644
--- a/gcc/cp/mangle.c
+++ b/gcc/cp/mangle.c
@@ -1506,8 +1506,8 @@ write_CV_qualifiers_for_type (type)
                     ::= m   # unsigned long
                     ::= x   # long long, __int64
                     ::= y   # unsigned long long, __int64  
-                    ::= n   # __int128            [not supported]
-                    ::= o   # unsigned __int128   [not supported] 
+                    ::= n   # __int128
+                    ::= o   # unsigned __int128
                     ::= f   # float
                     ::= d   # double
                     ::= e   # long double, __float80 
@@ -1552,13 +1552,18 @@ write_builtin_type (type)
 		write_char (integer_type_codes[itk]);
 		break;
 	      }
-	  
+
 	  if (itk == itk_none)
 	    {
 	      tree t = type_for_mode (TYPE_MODE (type), TREE_UNSIGNED (type));
 	      if (type == t)
-		/* Couldn't find this type.  */
-		abort ();
+		{
+		  if (TYPE_PRECISION (type) == 128)
+		    write_char (TREE_UNSIGNED (type) ? 'o' : 'n');
+		  else
+		    /* Couldn't find this type.  */
+		    abort ();
+		}
 	      type = t;
 	      goto iagain;
 	    }