[llvm-dev] Metadata in LLVM back-end

[David Greene via llvm-dev]

Son Tuan VU via llvm-dev <llvm-dev at lists.llvm.org> writes:

> Currently metadata (other than debug info) can be attached to IR
> instructions but disappears during DAG selection.
>
> My question is why we do not keep the metadata during code lowering and
> then attach to MachineInstr, just as for IR instructions? Is there any
> technical challenge, or is it only because nobody wants to do so?

I have wanted codegen metadata for a very long time so I'm interested to
hear the history behind this choice, and more importantly, whether
adding such capability would be generally acceptable to the community.

                -David