Missing vectorization with large, constant, loop trip counts

Hello,

icc 17 does not vectorize the following simple code:

int main(int argc, char const *argv[])
{
    #define SIZE 1024*1024*1024ULL

    unsigned long i;
    float *A,*B,*C;

    A = malloc(sizeof(float) * SIZE);
    B = malloc(sizeof(float) * SIZE);
    C = malloc(sizeof(float) * SIZE);

    for (i=0; i<SIZE; i++)
        C[i] = A[i] + B[i];

    printf("done %ld %f\n", SIZE, C[i]);

    return 0;
}

The vectorization report states:

LOOP BEGIN at main.c(12,5)
   remark #15523: loop was not vectorized: loop control variable i was found, but loop iteration count cannot be computed before executing the loop
   remark #25478: While Loop Unrolled by 2
LOOP END

, which does not make sense and looks like a bug. Reducing the SIZE value slightly (e.g., to 2^31-1), or removing the U from the integer qualifier at the end of the define (i.e., from ULL to LL) are workarounds.

Is this a known problem in icc? Are there any better workarounds?

Best regards,