diff --git a/src/lj_record.c b/src/lj_record.c
index 6c64c645..8a123a61 100644
--- a/src/lj_record.c
+++ b/src/lj_record.c
@@ -527,9 +527,9 @@ static LoopEvent rec_for(jit_State *J, const BCIns *fori, int isforl)
   TRef stop;
   IRType t;
   /* Avoid semantic mismatches and always failing guards. */
-  if (tvisnan(&tv[FORL_IDX]) ||
-      tvisnan(&tv[FORL_STOP]) ||
-      tvisnan(&tv[FORL_STEP]) ||
+  if ((tvisnum(&tv[FORL_IDX]) && tvisnan(&tv[FORL_IDX])) ||
+      (tvisnum(&tv[FORL_STOP]) && tvisnan(&tv[FORL_STOP])) ||
+      (tvisnum(&tv[FORL_STEP]) && tvisnan(&tv[FORL_STEP])) ||
       tvismzero(&tv[FORL_STEP]))
     lj_trace_err(J, LJ_TRERR_GFAIL);
   if (isforl) {  /* Handle FORL/JFORL opcodes. */