[LLVMdev] Complex load patterns and token factors

[Tim Northover]

> If it is not being used, maybe we should change it to be
> doesNotNeedChain?

That sounded like a really good idea until I started to actually go
through removing all traces of hasCtrlDep from other Targets. I felt
really bad about wiping those flags people had carefully put on their
instructions, even if useless.

> I am not sure what kind of load does not need to be chained (prefetch?), but I'd prefer to keep the system friendly if at
> all possible. They'll be fewer bugs that way.

That is the main worry. Could we justify a second "hasNoCtrlDep" in
addition to "hasCtrlDep", with it being a TableGen error to set both?
Or just forget about the override until someone actually comes up with
an instruction that's legitimately "mayLoad" or whatever yet doesn't
want a chain (I don't think even prefetch counts -- if other
instructions are modifying that location it needs to know).

> Thanks again,

No worries.

Tim.