This rewrite was necessary for the cases where the instruction contains a
reduction but the expression itself is not a reduction. Besides fixing this bug
it greatly reduces code duplication and increases code quality.

This just reverts to the old behaviour. The new implementation of loop
reordering doesn't need that anymore.

Still missing: Handling of reduction with haddsubst!

- Code cleanup
- Use loopys duplicate_inames
- 2D, 3D volumes and faces should all be working

This can be used to distinguish between kernels with the same name but
different transformations.

Merge branch 'feature/vcl-traits-stuff' into 'master'

ref:extensions/dune-codegen The VCL does not export enough information about
its types to reason about them, when they are used as template parameters. In
the long run, a proper solution will be needed I guess\...

See merge request [extensions/dune-codegen!321]

  [extensions/dune-codegen!321]: gitlab.dune-project.org/extensions/dune-codegen/merge_requests/321

Merge branch 'feature/adds-fma-node-to-subst-mapper' into 'master'

See merge request [extensions/dune-codegen!319]

  [extensions/dune-codegen!319]: Noneextensions/dune-codegen/merge_requests/319

Merge branch 'feature/print-likwid-warning' into 'master'

ref:extensions/dune-codegen I've already mentioned this problem in \[!314\]
but I think more visibility for this problem is useful

See merge request [extensions/dune-codegen!318]

  [extensions/dune-codegen!318]: gitlab.dune-project.org/extensions/dune-codegen/merge_requests/318

I've already mentioned this problem in [!314] but I think more
visibility for this problem is useful

Merge branch 'feature/likwid-performance-measuring' into 'master'

ref:extensions/dune-codegen This aims to enable performance measuring with
likwid. Currently on instrumentation levels \<= 3 are supported.

Additionally, executables with likwid instrumentation need to be linked
against likwid and I'm not sure how to achieve that.

See merge request [extensions/dune-codegen!314]

  [extensions/dune-codegen!314]: gitlab.dune-project.org/extensions/dune-codegen/merge_requests/314

Merge branch 'bugfix/cmake-google-benchmark' into 'master'

See merge request [extensions/dune-codegen!316]

  [extensions/dune-codegen!316]: Noneextensions/dune-codegen/merge_requests/316

Merge branch 'feature/fix-profiling-fullpath' into 'master'

ref:extensions/dune-codegen using which only works, if generate_operators is
in PATH, otherwise cmake fails. This is especially the case if dune-codegen is
configured completely new.

See merge request [extensions/dune-codegen!317]

  [extensions/dune-codegen!317]: gitlab.dune-project.org/extensions/dune-codegen/merge_requests/317

using which only works, if `generate_operators` is in `PATH`, otherwise cmake fails. This is especially the case if dune-codegen is configured completely new.