The trip count %trip_count% after loop unrolling is too small compared to the vector length %vl% . To fix: Prevent loop unrolling or decrease the unroll factor using a directive: #pragma nounroll or #pragma unroll.

Example

...
// Disable automatic loop unrolling using
#pragma nounroll
for (int i = 1; i < 100; i++)
...

void nounroll(int a[], int b[], int c[], int d[])
{
    // Disable automatic loop unrolling using
    #pragma nounroll
    for (int i = 1; i < 100; i++)
    {
        b[i] = a[i] + 1;
        d[i] = c[i] + 1;
    }
}