1 /* { dg-do compile } */
2 /* { dg-options "-O -ftree-loop-vectorize -fdump-tree-vect-details -fno-tree-loop-im -mavx2 -mprefer-vector-width=256" } */
3 
4 double x[1024][1024], red[1024];
foo(void)5 void foo (void)
6 {
7   for (int i = 0; i < 1024; ++i)
8     for (int j = 0; j < 1024; ++j)
9       {
10 	double v = i == 0 ? 0.0 : red[j];
11 	v = v + x[i][j];
12 	red[j] = v;
13       }
14 }
15 
16 /* { dg-final { scan-tree-dump "vectorization factor = 4" "vect" } } */
17