llvm/polly/lib/External/isl/test_inputs/convex5.polylib

2 4
0 1 0 -2
0 0 1 -6

2 4
0 1 0 -1
0 0 1 -4

3 4
0 -2 1 -2
1  1 0 -1
1 -1 0  2