[Bug target/95905] Failure to optimize _mm_unpacklo_epi8 with 0 as right operand to _mm_cvtepu8_epi16

[gabravier at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95905

--- Comment #1 from Gabriel Ravier <gabravier at gmail dot com> ---
The same pattern with _mm_unpacklo_epi16/32 and the corresponding SSE4
intrinsics can also be optimized in the same way.