Re: [PATCH 1/2] s/390: Implement "target" attribute.

[Andreas Krebbel <krebbel@linux.vnet.ibm.com>]

On 11/02/2015 09:44 AM, Dominik Vogt wrote:
> (@Uli: I'd like to hear your opinion on this issue.
> Original message:
> https://gcc.gnu.org/ml/gcc-patches/2015-10/msg03403.html).
> 
> On Fri, Oct 30, 2015 at 03:09:39PM +0100, Andreas Krebbel wrote:
>> Why do we need x_s390_arch_specified and x_s390_tune_specified?  You
>> should be able to use opts_set->x_s390_arch and opts_set->x_s390_tune
>> instead? (patch attached, your tests keep working with that change).
> 
> The idea was that -mtune on the command line is *not* overridden
> by the "arch" target attribute.  This would allow to change the
> architecture for a specific function and keep the -mtune= option
> from the command line.  But as a matter of fact, the current patch
> doesn't do it either (bug?).

Your testcases even seem to check for this behavior so it looked intentional to me.  But I agree
that being able to keep the -mtune cmdline value for a function while only changing the used
instruction set would be good.

Could you please elaborate why implementing this requires the new flags?

-Andreas-