[Bug c/49859] gcc could warn about statements between "switch" and first "case"

["wkoszek at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49859

--- Comment #3 from Wojciech Koszek <wkoszek at gmail dot com> 2011-07-27 01:28:28 UTC ---
Looks like GCC and Clang both agree on Duff's stuff:

wkoszek@wkoszek:~/p/duff$ cat duff.c
#include <stdio.h>

void
duff(to, from, count)
register short *to, *from;
register int count;
{
        register int n=(count+7)/8;
        switch(count%8){
        case 0:      do{      *to = *from++;
        case 7:              *to = *from++;
        case 6:              *to = *from++;
        case 5:              *to = *from++;
        case 4:              *to = *from++;
        case 3:              *to = *from++;
        case 2:              *to = *from++;
        case 1:              *to = *from++;
                }while(--n>0);
        }
}

int
main(int argc, char **argv)
{
    short    *dummy = NULL;

    (void)argc;
    (void)argv;

    duff(dummy, dummy, 123);
    return 0;
}
wkoszek@wkoszek:~/p/duff$ gcc -Wall -pedantic -Wunreachable-code -c duff.c
wkoszek@wkoszek:~/p/duff$ clang -Wall -pedantic -Wunreachable-code -c duff.c