isl_basic_set_preimage: avoid NULL pointer dereference

[isl.git] / test_inputs / philippe3vars3pars.pwqp

[N, M, L] -> { [i, j, k] -> (((1/2 * i + 1/2 * i^2) + j) + k^3) : i >= 0 and k >= -N + i and k >= -M - j and j <= L + i and L >= 0 and L >= -M }