Re: [ARM] [2/2] Fix DImode addressing

[Ramana Radhakrishnan <ramana dot radhakrishnan at arm dot com>]

Hi Jie,

I'm not sure I totally understand your patch. 


On Wed, 2010-12-22 at 14:41 +0800, Jie Zhang wrote: 
> Based on Ricard's explanation, it will be good to allow larger index 
> range for DImode addressing on modern ARM chips. Like this patch does. I 
> use multiple_operation_profitable_p to decide if it's good to use LDM or 
> not. Currently multiple_operation_profitable_p is not fine tuned. In 
> future the four conditionals about "low" in

Is this even going to work ? The patch didn't seem to define
multiple_operation_profitable_p anywhere.


> 
> +         if ((low != -8 && low != -4 && low != 0 && low != 4)
> +             || !multiple_operation_profitable_p (false, 2, val))
> 
> should be moved into multiple_operation_profitable_p.

Since the code is identical - why not move it in there today or is that
what you are saying ? Ideally I think it would be better to move this in
as a flag into the costs structure per core .

> 
> It's still under testing. Is it OK if the result is good?

What is the size or performance impact of this on something like
SPECINT2k ? I thought that vortex or was it chess in there that uses a
bit of DImode arithmetic ?

cheers
Ramana 
> 
> 
> Regards,