diff --git a/src/corelib/tools/qhashfunctions.h b/src/corelib/tools/qhashfunctions.h
index f34c26d4985..273a211a990 100644
--- a/src/corelib/tools/qhashfunctions.h
+++ b/src/corelib/tools/qhashfunctions.h
@@ -139,7 +139,7 @@ Q_DECL_CONST_FUNCTION constexpr inline size_t qHash(qint64 key, size_t seed = 0)
     }
     return qHash(quint64(key), seed);
 }
-#if QT_SUPPORTS_INT128
+#ifdef QT_SUPPORTS_INT128
 constexpr size_t qHash(quint128 key, size_t seed = 0) noexcept
 {
     return qHash(quint64(key + (key >> 64)), seed);
diff --git a/tests/auto/corelib/global/qfloat16/tst_qfloat16.cpp b/tests/auto/corelib/global/qfloat16/tst_qfloat16.cpp
index 5f1ff673169..07507ae6ae4 100644
--- a/tests/auto/corelib/global/qfloat16/tst_qfloat16.cpp
+++ b/tests/auto/corelib/global/qfloat16/tst_qfloat16.cpp
@@ -214,7 +214,7 @@ void tst_qfloat16::ordering()
         CHECK_INT(qint16);
         CHECK_INT(qint32);
         CHECK_INT(qint64);
-#if QT_SUPPORTS_INT128
+#ifdef QT_SUPPORTS_INT128
         CHECK_INT(qint128);
 #endif
         if (right >= 0) {
@@ -224,7 +224,7 @@ void tst_qfloat16::ordering()
             CHECK_INT(quint16);
             CHECK_INT(quint32);
             CHECK_INT(quint64);
-    #if QT_SUPPORTS_INT128
+    #ifdef QT_SUPPORTS_INT128
             CHECK_INT(quint128);
     #endif
         }
diff --git a/tests/auto/corelib/global/qglobal/qglobal.c b/tests/auto/corelib/global/qglobal/qglobal.c
index 2cfbd5e3be0..c133ad97fc3 100644
--- a/tests/auto/corelib/global/qglobal/qglobal.c
+++ b/tests/auto/corelib/global/qglobal/qglobal.c
@@ -59,7 +59,7 @@ void tst_GlobalTypes()
 #endif /* QT_SUPPORTS_INT128 */
 }
 
-#if QT_SUPPORTS_INT128
+#ifdef QT_SUPPORTS_INT128
 qint128 tst_qint128_min() { return Q_INT128_MIN + 0; }
 qint128 tst_qint128_max() { return 0 + Q_INT128_MAX; }
 quint128 tst_quint128_max() { return Q_UINT128_MAX - 1 + 1; }
diff --git a/tests/auto/corelib/global/qglobal/tst_qglobal.cpp b/tests/auto/corelib/global/qglobal/tst_qglobal.cpp
index 7dd027160ed..954eab6a43a 100644
--- a/tests/auto/corelib/global/qglobal/tst_qglobal.cpp
+++ b/tests/auto/corelib/global/qglobal/tst_qglobal.cpp
@@ -103,7 +103,7 @@ extern "C" {        // functions in qglobal.c
 void tst_GlobalTypes();
 int tst_QtVersion();
 const char *tst_qVersion();
-#if QT_SUPPORTS_INT128
+#ifdef QT_SUPPORTS_INT128
 qint128 tst_qint128_min();
 qint128 tst_qint128_max();
 quint128 tst_quint128_max();
diff --git a/tests/auto/corelib/global/qtendian/tst_qtendian.cpp b/tests/auto/corelib/global/qtendian/tst_qtendian.cpp
index 8e50b2bd088..6574c80ddf6 100644
--- a/tests/auto/corelib/global/qtendian/tst_qtendian.cpp
+++ b/tests/auto/corelib/global/qtendian/tst_qtendian.cpp
@@ -7,7 +7,7 @@
 #include <QtCore/private/qendian_p.h>
 #include <QtCore/qsysinfo.h>
 
-#if QT_SUPPORTS_INT128
+#ifdef QT_SUPPORTS_INT128
 #define ONLY_INT128(...) __VA_ARGS__
 #else
 #define ONLY_INT128(...)
diff --git a/tests/auto/corelib/tools/qhashfunctions/tst_qhashfunctions.cpp b/tests/auto/corelib/tools/qhashfunctions/tst_qhashfunctions.cpp
index beb3eb36c49..34ccd56e1d7 100644
--- a/tests/auto/corelib/tools/qhashfunctions/tst_qhashfunctions.cpp
+++ b/tests/auto/corelib/tools/qhashfunctions/tst_qhashfunctions.cpp
@@ -169,7 +169,7 @@ static void unsignedIntegerConsistency(quint64 value, size_t seed)
     if (v32 == value)
         QCOMPARE(hu64, hu32);
 
-#if QT_SUPPORTS_INT128
+#ifdef QT_SUPPORTS_INT128
     const auto hu128 = qHash(quint128(value), seed);
     QCOMPARE(hu128, hu64);
 #endif
@@ -216,7 +216,7 @@ void tst_QHashFunctions::signedIntegerConsistency()
             QCOMPARE(hs64, hs32);
     }
 
-#if QT_SUPPORTS_INT128
+#ifdef QT_SUPPORTS_INT128
     const auto hs128 = qHash(qint128(value), seed);
     QCOMPARE(hs128, hs64);
 #endif