diff --git a/core/iwasm/interpreter/wasm_loader.c b/core/iwasm/interpreter/wasm_loader.c
index 10a20e313..fc68e5966 100644
--- a/core/iwasm/interpreter/wasm_loader.c
+++ b/core/iwasm/interpreter/wasm_loader.c
@@ -15624,7 +15624,9 @@ re_scan:
                     /* basic operation */
                     case SIMD_v128_const:
                     {
+#if WASM_ENABLE_FAST_INTERP != 0
                         uint64 high, low;
+#endif
                         CHECK_BUF1(p, p_end, 16);
 #if WASM_ENABLE_FAST_INTERP != 0
                         wasm_runtime_read_v128(p, &high, &low);