[OpenRISC] [PATCH v3 3/3] or1k: gcc: initial support for openrisc

Stafford Horne
2018-10-30T12:49:18Z

Hello,

On Sun, Oct 28, 2018 at 05:54:47PM -0500, Segher Boessenkool wrote:
> Hi!
>
> On Mon, Oct 29, 2018 at 06:47:23AM +0900, Stafford Horne wrote:
> > On Sat, Oct 27, 2018 at 09:57:30PM -0500, Segher Boessenkool wrote:
> > > > +/* Helper for defining INITIAL_ELIMINATION_OFFSET.
> > > > + We allow the following eliminiations:
> > > > + FP -> HARD_FP or SP
> > > > + AP -> HARD_FP or SP
> > > > +
> > > > + HFP and AP are the same which is handled below. */
> > > > +
> > > > +HOST_WIDE_INT
> > > > +or1k_initial_elimination_offset (int from, int to)
> > >
> > > You could calculate this as some_offset (from) - some_offset (to) with
> > > some_offset a simple helper function. That gives you all possible
> > > eliminations :-)
> > >
> > > (Each offset is very cheap to compute in your case, so that's not a problem).
> >
> > Right, Do you mean something like the following? I think it would work, but I
> > am not sure it make the code easier to read. Do you think there would be much
> > benefits supporting all possible eliminations?
>
> Yes, like that. It also easily can handle the other combos (those with
> STACK_POINTER), and it is easier if you have to switch FRAME_GROWS_DOWNWARD
> ("false" is better on some args, but "true" is required for ssp).
>
> Your code is fine as-is of course.

Just to be clear, when you say 'as-is' did you mean the original v3 patch? Or
are you referring to followup patch I posted with the some_offset (from) -
some_offset (to) logic.

-Stafford