[PATCH 2/9] S/390: Add disabled insn attribute

[Ulrich Weigand]

Andreas Krebbel wrote:
> On 02/01/2016 02:45 PM, Ulrich Weigand wrote:
> > So I'm wondering what the difference is between this and simply
> > overriding the default implementation of "enabled" per-insn?
> > 
> > So instead of adding
> >     (set_attr "disabled" "0,1")])
> > to an insn, you might simply add instead:
> >     (set_attr "enabled" "*,0")])
> Not sure but wouldn't this mean that the value of the enabled attribute would then depend on the
> order of the set_attr for "enabled" and "cpu_facility" since one is defined on the value of the other?!

I don't think the order matches; genattrtab seems to first read in all .md
files and only then optimize and then emit definitions of all the get_attr_...
functions.  The eq_attr uses in the "enabled" definition would only be
evaluated at that point.

Bye,
Ulrich

-- 
  Dr. Ulrich Weigand
  GNU/Linux compilers and toolchain
  Ulrich.Weigand@de.ibm.com