--- a/Source/JavaScriptCore/wasm/WasmFaultSignalHandler.cpp
+++ b/Source/JavaScriptCore/wasm/WasmFaultSignalHandler.cpp
@@ -118,7 +118,11 @@ void unregisterCode(void* start, void* e
 
 bool fastMemoryEnabled()
 {
+#if ENABLE(WEBASSEMBLY_FAST_MEMORY)
     return fastHandlerInstalled;
+#else
+    return false;
+#endif // ENABLE(WEBASSEMBLY_FAST_MEMORY)
 }
 
 void enableFastMemory()