Because of me not understanding the LLVM pass structure well, I did not find a
good way to allocate isl_ctx and to free it later without getting issues with
reference counting. I now found this place, such that we can free isl_ctx. This
patch also fixes the memory leaks that were ignored beforehand.
llvm-svn: 138204
Instead of returning a pointer to the domain, we return a new copy of it. This
is safer, as we do not give access to internal objects. It is also not
expensive, as isl will just increment a reference counter.
llvm-svn: 131010
