On Wed, 12 Jun 2024, Paolo Bonzini wrote:
> Ahah, nice. :) I'm pretty sure that, when I tested "pf = > (__builtin_popcount(x) & 1) * 4;", it was generating a call to > __builtin_popcountsi2. Why write '__builtin_popcount(x) & 1' when you can write '__builtin_parity(x)' in the first place? > Still - for something that has a code generator, there _is_ a cost in > supporting old CPUs, so I'd rather avoid reverting this. The glibc bug > that you linked is very different not just because it affected 32-bit > installation media, but also because it was a bug rather than > intentional. > > Since you are reporting this issue, how did you find out / what broke for you? I found out from the mailing list. My Core2-based desktop would be affected. Last but not the least, I'm sympathetic to the efforts of my distro maintainers, who I imagine would be put in an uncomfortable position by this change. Alexander
