diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 9405df9945e0..296b55ab684f 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2016-09-27  David Edelsohn  <dje.gcc@gmail.com>
+
+	Backport from mainline
+	2016-09-27  David Edelsohn  <dje.gcc@gmail.com>
+
+	* config/rs6000/rs6000.c (rs6000_output_symbol): Don't modify
+	VAR_DECL string.
+
 2016-09-27  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/77478
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 8900b4ce20d0..88f4e6c27d7c 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -26231,7 +26231,10 @@ rs6000_output_symbol_ref (FILE *file, rtx x)
 		     (TREE_CODE (decl) == FUNCTION_DECL
 		      ? "[DS]" : "[UA]"),
 		     NULL);
-      XSTR (x, 0) = name;
+
+      /* Don't modify name in extern VAR_DECL to include mapping class.  */
+      if (TREE_CODE (decl) == FUNCTION_DECL)
+	XSTR (x, 0) = name;
     }
 
   if (VTABLE_NAME_P (name))