diff --git a/library/dialect/swi/fli/swi.c b/library/dialect/swi/fli/swi.c
index acda0f49a..7ff1df69b 100644
--- a/library/dialect/swi/fli/swi.c
+++ b/library/dialect/swi/fli/swi.c
@@ -57,6 +57,7 @@ static int
 do_gc(UInt sz)
 {
   /* always called from user_call_cpred */
+  CACHE_REGS
   UInt arity;
   yamop *nextpc;