Re: [PATCH,vect] ppc cost model options

[Dorit Nuzman <DORIT at il dot ibm dot com>]

David Edelsohn <dje@watson.ibm.com> wrote on 19/10/2007 14:43:01:

> Dorit,
>
>    I am enabling VMX auto-vectorization for AIX 5.3.  Most testcases
> succeed.  You can see the failures in the recent testresults.
>
>    One set of failures is due to the ppc costmodel using -mcpu=7400.
> AIX does not run on that processor and does not support that option to
> invoke the AIX assembler properly.
>
>    I would like to change the compile-only option to -mcpu=970, which
> is supported by AIX.  Is there a reason to prefer 7400 instead of 970?
>

970 sounds ok to me. I don't know why it's currently set to 7400 - I think
I just copied-and-pasted this code from vect.exp in gcc.dg/vect/. Maybe
Janis remembers why it was set to 7400.

dorit

(by the way - I wouldn't spend too much time fixing dg-final failures in
the cost-model sub-directory at the moment (e.g. wrong number of loops gets
vectorized and such) because the vectorizer cost-model is pending some
fixes from Harsha (http://gcc.gnu.org/ml/gcc-patches/2007-09/msg00916.html
), to be followed by target-specific tuning of costs.)

> Thanks, David
>
>      * gcc.dg/vect/costmodel/ppc/ppc-costmodel-vect.exp: Use
>    -mcpu=970 instead of 7400.
>
> Index: ppc-costmodel-vect.exp
> ===================================================================
> --- ppc-costmodel-vect.exp   (revision 129469)
> +++ ppc-costmodel-vect.exp   (working copy)
> @@ -49,7 +49,7 @@
>  } else {
>      if [is-effective-target ilp32] {
>          # Specify a cpu that supports VMX for compile-only tests.
> -        lappend DEFAULT_VECTCFLAGS "-mcpu=7400"
> +        lappend DEFAULT_VECTCFLAGS "-mcpu=970"
>      }
>      set dg-do-what-default compile
>  }