[llvm-dev] Unknown Target Node

[Tim Northover via llvm-dev]

On Sat, 2 Mar 2019 at 21:00, preejackie via llvm-dev
<llvm-dev at lists.llvm.org> wrote:
> Could you please explain how you are using this? like commands
>
> When I run this IR in opt, it doesn't throw any errors.

The error he's reporting is from CodeGen, so opt would never be able
to reproduce it (you'd have to use llc). I haven't tried, but the
input is so basic I assume it's also from a private backend.

Unfortunately I can only speculate about the cause. LLVM doesn't
usually even try to select machine nodes, so the best idea I've come
up with is that some custom selection code is both modifying the DAG
and then reporting failure to select. The key questions Josh needs to
look into are:

  + Is this node there in -view-isel-dags (i.e. before selection)?
  + If not, what creates it (this'll probably involve looking at
build/lib/Target/XYZ/XYZGenInstrInfo.inc to work out what 284 is.

Calls are pretty special at the best of times, but I can't think of a
way they could cause this.

Tim.