diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f12c5a8ed1a..7017ba0ec4a 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+Mon Mar 16 15:57:17 1998  Michael Meissner  <meissner@cygnus.com>
+
+	* gcc.c (default_arg): Don't wander off the end of allocated
+	memory.
+
 Mon Mar 16 12:55:15 1998  Jim Wilson  <wilson@cygnus.com>
 	
 	* config/m68k/netbsd.h (ASM_SPEC): Add %{m68060}.
diff --git a/gcc/gcc.c b/gcc/gcc.c
index 1b0b9fa9da9..c558de3beac 100644
--- a/gcc/gcc.c
+++ b/gcc/gcc.c
@@ -5235,6 +5235,9 @@ default_arg (p, len)
 
       if ((end - start) == len && strncmp (p, start, len) == 0)
 	return 1;
+
+      if (*end == '\0')
+	break;
     }
 
   return 0;