So, completed bootstrap and regression-test for x86_64-unknown-linux-gnu (multilib) by using following predicate for sibcall-patch.
(define_predicate "sibcall_memory_operand" (match_operand 0 "memory_operand") { return CONSTANT_P (op); }) Worked fine, no regressions. Is sibcall-patch ok with that predicate to be applied? Regards, Kai