Substring information on slice operation has been added in D112441.
The operations fir.array_load, fir.array_coor and fir.array_merge_store can take
a slice but not with a substring. This patch add this check in their verifier.
This patch is part of the upstreaming effort from fir-dev branch.
Co-authored-by: Eric Schweitz <eschweitz@nvidia.com>