Re: Popcount optimization using AVX512

Nathan Bossart <nathandbossart@gmail.com> writes:
> On Sun, Apr 07, 2024 at 08:23:32PM -0500, Nathan Bossart wrote:
>> The Intel documentation for _mm256_undefined_si256() [0]
>> indicates that it is intended to return "undefined elements," so it seems
>> like the use of an uninitialized variable might be intentional.

> See also https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;h=72af61b122.

Ah, interesting.  That hasn't propagated to stable distros yet,
evidently (and even when it does, I wonder how soon Coverity
will understand it).  Anyway, that does establish that it's
gcc's problem not ours.  Thanks for digging!

            regards, tom lane