route(8) core dump, possible gcc(1) related

Hello,

gcc w/ default flags:

# route add 172.19.16.0.0/16 10.10.10.2
zsh: segmentation fault (core dumped)

gcc -O0:

# route add 172.19.16.0.0/16 10.10.10.2
route: bad address: 172.19.16.0.0/16

I failed to find any bugs in this code snippet where route(8)
dumps a core (line 1041):

 1033           q = strchr(s,'/');
 1034           if (q && which == RTA_DST) {
 1035                   *q = '\0';
 1036                   if ((val = inet_network(s)) != INADDR_NONE) {
 1037                           inet_makenetandmask(
 1038                                   val, &su->sin, strtoul(q+1, 0, 0));
 1039                           return (0);
 1040                   }
 1041                   *q = '/';
 1042           }

Any comments?

-- 
Maxim Konovalov