--- old/src/hotspot/share/utilities/globalDefinitions_gcc.hpp	2020-08-04 04:06:01.942800328 -0400
+++ new/src/hotspot/share/utilities/globalDefinitions_gcc.hpp	2020-08-04 04:06:01.462784471 -0400
@@ -159,6 +159,7 @@
 // Inlining support
 #define NOINLINE     __attribute__ ((noinline))
 #define ALWAYSINLINE inline __attribute__ ((always_inline))
+#define ATTRIBUTE_FLATTEN __attribute__ ((flatten))
 
 // Alignment
 //