diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d440252d9f3..c80c41a8a6f 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -24,6 +24,7 @@
 	(tle_get_tpointer_internal): New.
 	(tls_get_addr<mode>): New.
 	(tls_get_addr_internal<mode>): New.
+	* config/rs6000/xcoff.h (ASM_OUTPUT_TLS_COMMON): Define.
 
 2012-11-30  Teresa Johnson  <tejohnson@google.com>
 
diff --git a/gcc/config/rs6000/xcoff.h b/gcc/config/rs6000/xcoff.h
index e5c47822355..15f8bbf5e3e 100644
--- a/gcc/config/rs6000/xcoff.h
+++ b/gcc/config/rs6000/xcoff.h
@@ -304,6 +304,15 @@
 		xcoff_bss_section_name);		\
      } while (0)
 
+#ifdef HAVE_AS_TLS
+#define ASM_OUTPUT_TLS_COMMON(FILE, DECL, NAME, SIZE)	\
+  do { fputs(COMMON_ASM_OP, (FILE));			\
+       RS6000_OUTPUT_BASENAME ((FILE), (NAME));		\
+       fputs("[UL]", (FILE));					\
+       fprintf ((FILE), ","HOST_WIDE_INT_PRINT_UNSIGNED"\n", (SIZE)); \
+  } while (0)
+#endif
+
 /* This is how we tell the assembler that two symbols have the same value.  */
 #define SET_ASM_OP "\t.set "