diff --git a/gcc/config/rs6000/linux64.h b/gcc/config/rs6000/linux64.h
index c605847ac84..b34be5ce198 100644
--- a/gcc/config/rs6000/linux64.h
+++ b/gcc/config/rs6000/linux64.h
@@ -33,6 +33,8 @@ Boston, MA 02111-1307, USA.  */
 
 #undef PROCESSOR_DEFAULT
 #define PROCESSOR_DEFAULT PROCESSOR_PPC630
+#undef PROCESSOR_DEFAULT64
+#define PROCESSOR_DEFAULT64 PROCESSOR_PPC630
 
 #undef  CPP_DEFAULT_SPEC
 #define CPP_DEFAULT_SPEC "-D_ARCH_PPC64"