--- a/cache.cxx	
+++ a/cache.cxx	
@@ -8,2 +8,10 @@ 
 
+#ifdef __ia64__
+// Default is: nor
+// We disable 'o' because gcc fails to select register
+// constraint for second instruction in 'add_script_to_cache'
+//     https://bugs.gentoo.org/510134
+#    define STAP_SDT_ARG_CONSTRAINT nr
+#endif
+
 #include "config.h"