+#if !defined(_PDCLIB_UNREACHABLE) && _PDCLIB_GCC_BUILTIN(__builtin_unreachable, 4, 0)
+ #define _PDCLIB_UNREACHABLE __builtin_unreachable()
+#endif
+
+#if !defined(_PDCLIB_UNDEFINED) && defined(__GNUC__)
+ #define _PDCLIB_UNDEFINED(_var) \
+ do { __asm__("" : "=X"(_var)); } while(0)
+#endif
+