isl_test_cpp17-generic.cc: work around std::optional::value issue in older macOS

[isl.git] / test_inputs / flow / loop.ai

sink: { S[] -> a[] }
must_source: { T[i] -> a[] : 0 <= i < 10 }
schedule_map: { T[i] -> [0,i]; S[] -> [1,0] }