diff --git a/intern/cycles/kernel/device/metal/kernel.metal b/intern/cycles/kernel/device/metal/kernel.metal
index d1fee476a9f..494f13eb9f9 100644
--- a/intern/cycles/kernel/device/metal/kernel.metal
+++ b/intern/cycles/kernel/device/metal/kernel.metal
@@ -4,9 +4,13 @@
 
 /* Metal kernel entry points. */
 
+/* NOTE: Must come prior to other includes. */
 #include "kernel/device/metal/compat.h"
 #include "kernel/device/metal/globals.h"
+
+/* NOTE: Must come prior to the kernel.h. */
 #include "kernel/device/metal/function_constants.h"
+
 #include "kernel/device/gpu/kernel.h"
 
 /* MetalRT intersection handlers. */