VM_CALL_TAILCALL_BIT 1730 compile.c      	    piobj->operands[3] = INT2FIX(FIX2INT(piobj->operands[3]) | VM_CALL_TAILCALL_BIT);
VM_CALL_TAILCALL_BIT  440 vm_insnhelper.c     if (LIKELY(!(flag & VM_CALL_TAILCALL_BIT))) {