diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 07dceaabe92..32813b45a12 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2016-05-20  David Malcolm  <dmalcolm@redhat.com>
+
+	* calls.c (can_implement_as_sibling_call_p): Mark param
+	reg_parm_stack_space with ATTRIBUTE_UNUSED.
+
 2016-05-20  Uros Bizjak  <ubizjak@gmail.com>
 
 	* gcc/config/i386/i386.c (ix86_rtx_costs) <case CONST_DOUBLE>:
diff --git a/gcc/calls.c b/gcc/calls.c
index 1b12ecaa7b9..587969fcf01 100644
--- a/gcc/calls.c
+++ b/gcc/calls.c
@@ -2373,7 +2373,7 @@ static bool
 can_implement_as_sibling_call_p (tree exp,
 				 rtx structure_value_addr,
 				 tree funtype,
-				 int reg_parm_stack_space,
+				 int reg_parm_stack_space ATTRIBUTE_UNUSED,
 				 tree fndecl,
 				 int flags,
 				 tree addr,