On Thu, Jan 21, 2016 at 11:13:29AM +0000, Wilco Dijkstra wrote:
> James Greenhalgh <james.greenha...@arm.com> wrote:
> > If we don't have any targets which care about the fccmps/fccmpd split in
> > the code base, do we really need it? Can we just follow the example of
> > fcsel?
>
> If we do that then we should also change fcmps/d to fcmp to keep the f(c)cmp
> attributes orthogonal. However it seems better to have all FP operations use
> {s|d} postfix as the convention (rather than assume that all current and
> future
> microarchitectures will treat float and double identically on all operations),
> so fcsel should ideally be fixed.
Adding values to this type attributes is a pretty lightweight change, and
each new type attribute has a small cost in compiler build-time and scheduler
performance. Given this, I don't see any need to design for the future, and
I don't see why we'd want to add more of them than we need to.
The fcmps/fcmpd split is used in cortex-a15-neon.md and cortex-r4f.md so
doesn't make a good comparison.
If we support a target in future which would benefit from different
modeling for fccmps and fccmpd we can split the value then.
Thanks,
James
