diff --git a/src/gallium/drivers/radeon/SIGenRegisterInfo.pl b/src/gallium/drivers/radeon/SIGenRegisterInfo.pl
index 3813eb5ad12..48bd5676eb0 100644
--- a/src/gallium/drivers/radeon/SIGenRegisterInfo.pl
+++ b/src/gallium/drivers/radeon/SIGenRegisterInfo.pl
@@ -241,7 +241,7 @@ if ($INDEX_FILE ne '') {
     }
     print $fh "    return $key;\n";
   }
-  print $fh "  default: return 0;\n  }\n}\n"
+  print $fh "  default: assert(!\"Unknown Register\"); return 0;\n  }\n}\n"
 }