[Bug tree-optimization/101590] (len & - N) <= len is not optimized to 1

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101590

--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
We should also handle:
int foo(int len, int N) {
        len &= 0xffff;
        N &= 0xff;
        int newlen = len & ~N;
        return newlen <= len;
}

That is 
(TREE_UNSIGNED (TREE_TYPE (@0))
 || (signbit(@0) == 0 && signbit(@1) == 0))