Calls to auto-vectorized AVX512 functions

[Naoki Shibata via Gcc]

Hello,

I have a question as to the auto-vectorizer in GCC.

When AVX512 instruction is available, the auto-vectorizer in gcc 
sometimes generates calls to AVX2 functions instead of AVX512 functions.


$ cat vabitest.c
#include <stdio.h>
#include <math.h>

_Pragma ("omp declare simd simdlen(8) notinbranch") 
__attribute__((const)) double myfunc(double x);

#define N 1024
__attribute__ ((__aligned__(256))) double a[N], b[N], c[N];

int main(void) {
  for (int i = 0; i < N; i++) a[i] = myfunc(b[i]);
  for (int i = 0; i < N; i++) c[i] = sin(b[i]);
}

$ gcc-10 -ffast-math -O3 -mavx512f -fopenmp vabitest.c -S -o- | grep _ZGV
        call    _ZGVdN8v_myfunc@PLT
        call    _ZGVeN8v_sin@PLT


Is there a way to force gcc to generate calls to AVX512 function in 
cases like this?

Regards,

Naoki Shibata