diff --git a/js/src/vm/BigIntType.cpp b/js/src/vm/BigIntType.cpp
index e2a6d11dc317..4e28a0032655 100644
--- a/js/src/vm/BigIntType.cpp
+++ b/js/src/vm/BigIntType.cpp
@@ -251,7 +251,7 @@ BigInt* BigInt::neg(JSContext* cx, HandleBigInt x) {
 #if !defined(JS_64BIT)
 #  define HAVE_TWO_DIGIT 1
 using TwoDigit = uint64_t;
-#elif defined(HAVE_INT128_SUPPORT)
+#elif defined(__SIZEOF_INT128__)
 #  define HAVE_TWO_DIGIT 1
 using TwoDigit = __uint128_t;
 #endif