G3/G4 -march flags?

G3/G4 -march flags?

[Jack Lloyd]

Hi,

Are there any extra flags beyond the usual optimization flags that I could
pass to GCC (2.95.x, 3.0.x, or 3.1.x) which would usefully optimize an
integer-intensive program on a G3 or G4?

Thanks,
  Jack

Re: G3/G4 -march flags?

[David Edelsohn]

>>>>> Jack Lloyd writes:

Jack> Are there any extra flags beyond the usual optimization flags that I could
Jack> pass to GCC (2.95.x, 3.0.x, or 3.1.x) which would usefully optimize an
Jack> integer-intensive program on a G3 or G4?

	See the GCC documentation for which flags are available with each
release of GCC.  GCC 3.1 supports -mcpu=740, -mcpu=750, -mcpu=7400,
-mcpu=7450.

David

Re: G3/G4 -march flags?

[Daniel Egger]

Am Mit, 2002-05-08 um 18.00 schrieb Jack Lloyd:

> Are there any extra flags beyond the usual optimization flags that I could
> pass to GCC (2.95.x, 3.0.x, or 3.1.x) which would usefully optimize an
> integer-intensive program on a G3 or G4?

Assuming you're talking about a PowerPC machine the answer is no, not
really. You can pass -mcpu=7400 and -mtune=7400 above 3.0 (IIRC) but
this will affect scheduling just slightly. The difference between the 
PPC750 (G3) and the 7400 (G4) is minimal while the 7450 (newer G4s) 
have a longer pipeline and other changes to achieve higher clock speeds;
using -mcpu=7450 -mtune=7450 in 3.1 or CVS might help here but I such a 
machine to benchmark it.
 
-- 
Servus,
       Daniel

Re: G3/G4 -march flags?

[Bryce McKinlay]

Jack Lloyd wrote:

>Are there any extra flags beyond the usual optimization flags that I could
>pass to GCC (2.95.x, 3.0.x, or 3.1.x) which would usefully optimize an
>integer-intensive program on a G3 or G4?
>  
>

You can try -mcpu=750 for G3, and -mcpu=7400 or -mcpu=7450 for G4. See 
the manual for more information.

regards

Bryce.