// packed vector of 2-elements
typedef double v2d __attribute__((vector_size(sizeof(double)*2)));

v2d x = ...;
double y = ...;

x[0] = pow(x[0], y)
x[1] = pow(x[1], y)

#include <math.h>
typedef double vnd __attribute__((vector_size(sizeof(double)*2)));

vnd foo(vnd x, vnd y) {
    #pragma omp simd
    for(int i=0; i<2; i++) x[i] = pow(x[i], y[i]);
    return x;
}