[Bug target/82731] _mm256_set_epi8(array[offset[0]], array[offset[1]], ...) byte gather makes slow code, trying to zero-extend all the uint16_t offsets first and spilling them.

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82731

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note you can reproduce the same issue with SSE2 (and not just AVX):
```

#define vect16 __attribute__((vector_size(16)))

vect16 char gather(char *array, unsigned short *offset) {

  return (vect16 char){array[offset[0]], array[offset[1]], array[offset[2]],
array[offset[3]], array[offset[4]], array[offset[5]], array[offset[6]],
array[offset[7]],
      array[offset[8]],array[offset[9]],array[offset[10]],array[offset[11]],
array[offset[12]], array[offset[13]], array[offset[14]]};
}
```