diff --git a/gcc/gcse.cc b/gcc/gcse.cc
index 3f3f7fe15b0..4ae19f28430 100644
--- a/gcc/gcse.cc
+++ b/gcc/gcse.cc
@@ -4351,7 +4351,7 @@ public:
 }; // class pass_rtl_pre
 
 bool
-pass_hardreg_pre::gate (function *fun)
+pass_hardreg_pre::gate (function * ARG_UNUSED (fun))
 {
 #ifdef HARDREG_PRE_REGNOS
   return optimize > 0