diff --git a/src/lj_opt_narrow.c b/src/lj_opt_narrow.c
index 3085c837..a4a1c8ee 100644
--- a/src/lj_opt_narrow.c
+++ b/src/lj_opt_narrow.c
@@ -545,9 +545,9 @@ TRef lj_opt_narrow_unm(jit_State *J, TRef rc, TValue *vc)
   rc = conv_str_tonum(J, rc, vc);
   if (tref_isinteger(rc)) {
     uint32_t k = (uint32_t)numberVint(vc);
-    if ((LJ_DUALNUM || k != 0) && k != 0x80000000u) {
+    if ((tvisint(vc) || k != 0) && k != 0x80000000u) {
       TRef zero = lj_ir_kint(J, 0);
-      if (!LJ_DUALNUM)
+      if (!tvisint(vc))
 	emitir(IRTGI(IR_NE), rc, zero);
       return emitir(IRTGI(IR_SUBOV), zero, rc);
     }