[Bug tree-optimization/98299] Failure to optimize sub loop into modulo-based pattern

[gabravier at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98299

--- Comment #3 from Gabriel Ravier <gabravier at gmail dot com> ---
PS: The optimization seems to already occur for simpler cases such as powers of
2, e.g. :

int f1(int n)
{
    while (n >= 64)
        n -= 64;

    return n;
}

is optimized into `return (n <= 63) ? n : (n & 63);`.