End-to-end test: reduction

[lukasrothenberger]

{
int i, j;

for (i = 0; i < _PB_NY; i++)
y[i] = 0;
for (i = 0; i < _PB_NX; i++) # this is not a reduction loop
{
tmp[i] = 0;
for (j = 0; j < _PB_NY; j++) ## this is a reduction loop
tmp[i] = tmp[i] + A[inx+j] * x[j];
for (j = 0; j < _PB_NY; j++) ## this is not a reduction loop
y[j] = y[j] + A[inx+j] * tmp[i];
}

}