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| Subject: | Re: GCC 4.3.0: Stage 3 |
| Group: | Gcc |
| From: | Ian Lance Taylor |
| Date: | 22 Sep 2007 |
"Andreas Krebbel" <Andreas.Krebbel> writes:
> The lengthy part is necessary to have attribute getter functions which
> allow to specify the alternative as additional parameter. I admit
> that these are a lot of quite mechanical changes to the genattr stuff
> but my hope was that these getter functions might be useful in other
> contexts as well.
I'm not sure how.
Right now you can refer to the attribute values for an alternative
when computing a different attribute for that alternative. Can you
use that ability to compute your enabled alternative?
> Misusing the constraint letters to enable or disable alternatives is a
> solution which is already used by back ends. On S/390 we have the 'O'
> constraint familiy which only returns true for machines providing the
> extended immediate facility. But actually this was one of the reasons
> why I wanted to change this. I think this is a non-obvious mixture of
> different concepts. The constraint letters should only depend on the
> type of the operand. Adding additional conditions to it could create a
> real mess.
OK, fair enough.
Ian
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