diff --git a/format.c b/format.c
index e859f08..171f983 100644
--- a/format.c
+++ b/format.c
@@ -127,6 +127,7 @@ fd_strpcatreg(char* restrict dst, unsigned rt, unsigned ri, unsigned size) {
 
 const char*
 fdi_name(FdInstrType ty) {
+    (void) ty;
     return "(invalid)";
 }