[Bug target/101956] Miss vectorization from v4hi to v4df

[crazylht at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101956

--- Comment #1 from Hongtao.liu <crazylht at gmail dot com> ---
test4.c:4:9: missed:   conversion not supported by target.

SLP expect {zero_,}extendv4hiv4df?

loop vectorizer can automatically try extendv8hiv8si + extendv4siv4df
void
foo1 (double* p, short* q, int n)
{
    for (int i = 0; i != n; i++)
      p[i] = q[i];
}