diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4fb2e2c8be4..06a8f166656 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,8 @@
 Wed Aug 26 15:55:41 1998  Jim Wilson  <wilson@cygnus.com>
 
+	* iris5.h (PREFERRED_DEBUGGING_TYPE): Undef.
+	* iris5gas.h (PREFERRED_DEBUGGING_TYPE): Define.
+
 	* configure.in (powerpc-ibm-aix4.[12]*): Change from 4.[12].*.
 	(rs6000-ibm-aix4.[12]*): Likewise.
 	* configure: Regnerate.
diff --git a/gcc/config/mips/iris5.h b/gcc/config/mips/iris5.h
index f81fe1c0fda..7910eef88d6 100644
--- a/gcc/config/mips/iris5.h
+++ b/gcc/config/mips/iris5.h
@@ -123,6 +123,7 @@ Boston, MA 02111-1307, USA.  */
 #undef DBX_DEBUGGING_INFO
 #undef SDB_DEBUGGING_INFO
 #undef MIPS_DEBUGGING_INFO
+#undef PREFERRED_DEBUGGING_TYPE
 
 /* Likewise, the assembler doesn't handle DWARF2 directives.  */
 #define DWARF2_UNWIND_INFO 0
diff --git a/gcc/config/mips/iris5gas.h b/gcc/config/mips/iris5gas.h
index f1c2c483f88..477a55fb647 100644
--- a/gcc/config/mips/iris5gas.h
+++ b/gcc/config/mips/iris5gas.h
@@ -4,6 +4,7 @@
 #define DBX_DEBUGGING_INFO
 #define SDB_DEBUGGING_INFO
 #define MIPS_DEBUGGING_INFO
+#define PREFERRED_DEBUGGING_TYPE SDB_DEBUG
 
 /* GNU as does handle DWARF2 directives.  */
 #undef DWARF2_UNWIND_INFO