https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68780
Guille <guille at cal dot berkeley.edu> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution|--- |INVALID
--- Comment #2 from Guille <guille at cal dot berkeley.edu> ---
Thanks for the explanation, you are exactly right.
Apologies for my misunderstanding.
(In reply to James Almer from comment #1)
> What i assume you want is _mm256_mullo_epi32(a, b), which maps to the
> vpmulld instruction (Multiply the packed 32-bit integers in a and b,
> producing intermediate 64-bit integers, and store the low 32 bits of the
> intermediate integers in dst), which for your testcase would result in eight
> 32-bit integers with value 2.
>
> _mm256_mul_epi32(a, b) maps to vpmuldq (Multiply the low 32-bit integers
> from each packed 64-bit element in a and b, and store the signed 64-bit
> results in dst), which for your testcase correctly gives four 64-bit
> integers with value 2.
