Similar when building Python on Fedora 30 (GCC version 9.2.1) with gcc -O3:

In function ‘getsockaddrarg’,
    inlined from ‘sock_bind’ at /home/vstinner/python/master/Modules/socketmodule.c:3113:10:
/home/vstinner/python/master/Modules/socketmodule.c:2331:9: warning: ‘memset’ offset [17, 88] from the object at ‘addrbuf’ is out of the bounds of referenced subobject ‘sa’ with type ‘struct sockaddr’ at offset 0 [-Warray-bounds]
 2331 |         memset(sa, 0, sizeof(*sa));
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~