diff --git a/gas/ChangeLog b/gas/ChangeLog
index ea3ee1b40a0..ba6d9ca7895 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,7 @@
+2018-08-09  H.J. Lu  <hongjiu.lu@intel.com>
+
+	* as.c (show_usage): Display default option for --elf-stt-common=.
+
 2018-08-09  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* config/tc-i386.c (md_show_usage): Display default options.
diff --git a/gas/as.c b/gas/as.c
index 02c7d2970bf..b2a908a2f75 100644
--- a/gas/as.c
+++ b/gas/as.c
@@ -301,7 +301,12 @@ Options:\n\
   --size-check=[error|warning]\n\
 			  ELF .size directive check (default --size-check=error)\n"));
   fprintf (stream, _("\
-  --elf-stt-common=[no|yes]\n\
+  --elf-stt-common=[no|yes] "));
+  if (DEFAULT_GENERATE_ELF_STT_COMMON)
+    fprintf (stream, _("(default: yes)\n"));
+  else
+    fprintf (stream, _("(default: no)\n"));
+  fprintf (stream, _("\
                           generate ELF common symbols with STT_COMMON type\n"));
   fprintf (stream, _("\
   --sectname-subst        enable section name substitution sequences\n"));