https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116355
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
gen_pow2p is where the issue is.
So there is a few ways of fixing this I think.
One is to convert to an unsigned type if not already.
But there is another way is to use __builtin_popcount{,l,ll} always and let
other passes optimize it into what the target wants.
Because `POPCOUNT(a) == 1` is not the same as `a & -a == a` either but rather:
int f(int a)
{
int b = a - 1;
return (unsigned)(b ^ a) > (unsigned)a;
}
You can see that with aarch64 code generation even:
cipher_to_alg:
sub w1, w0, #1
eor w2, w0, w1
cmp w2, w1
bls .L3
