diff --git a/gcc/config/i386/gas.h b/gcc/config/i386/gas.h
index 35fcbea37d1..00fc08a2da6 100644
--- a/gcc/config/i386/gas.h
+++ b/gcc/config/i386/gas.h
@@ -22,7 +22,7 @@ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
 
 #include "i386.h"
 
-#ifdef YES_UNDERSCORES
+#ifndef YES_UNDERSCORES
 /* Define this now, because bsd386.h tests it.  */
 #define NO_UNDERSCORES
 #endif
@@ -62,14 +62,6 @@ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
 
 #define ASM_OUTPUT_IDENT(FILE, NAME) fprintf (FILE, "\t.ident \"%s\"\n", NAME);
 
-/* We do not want to output SDB debugging information.  */
-
-#undef SDB_DEBUGGING_INFO
-
-/* We want to output DBX debugging information.  */
-
-#define DBX_DEBUGGING_INFO
-
 /* Implicit library calls should use memcpy, not bcopy, etc.  */
 
 #define TARGET_MEM_FUNCTIONS