[LLVMdev] Is metadata the right thing to associate one instruction to another?

[Steve King]

> On Mon, Jul 13, 2015 at 12:37 PM, Frank Winter <fwinter at jlab.org> wrote:
> Would be great to attach/store a (user) pointer to/along with an
> instruction..

Sounds nice to me too.  There would be many uses for a feature that
allows fast instruction associations, e.g. finding relaxations.  From
what I've noticed, targets handle this sort of problem with "brute
force" switch statements.