[Bug target/103571] ABI: V2HF, V4HF and V8HFmode argument passing issues

[crazylht at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103571

--- Comment #17 from Hongtao.liu <crazylht at gmail dot com> ---
(In reply to Hongtao.liu from comment #16)
> There're already testcases for vec_extract/vec_set/vec_duplicate, but those
> testcases are written under TARGET_AVX512FP16, i'll make a copy of them and
> test them w/o avx512fp16.

Also we can relax condition of extendv*hfv*sf and truncv*sfv*hf to
avx512vl/f16c so that vect-float16-1.c could be vectorized.

vect-float16-1.c

void
foo (_Float16 *__restrict__ a, _Float16 *__restrict__ b,
     _Float16 *__restrict__ c)
{
  for (int i = 0; i < 256; i++)
    a[i] = b[i] + c[i];
}