discouraging register use

[Richard Henderson]

On Thu, Dec 30, 2004 at 06:54:44PM -0500, DJ Delorie wrote:
> Do I have to do something like this?  If so, I'm going to have some
> *really* long lines in my md file (for this chip).  Or is there some
> other way of changing gcc's register preferences, without precluding
> the registers completely?
> 
>   [(set (match_operand:SI 0 "" "c,c,?m,?m")
>         (plus:SI (match_operand:SI 1 "" "0,0,0,0")
> 		 (match_operand:SI 1 "" "c,?m,c,?m")))]

Yes, that looks plausible.  The other way isn't going to work because
you penalize c at the same time as m by using "?cm".

Does it actually work?


r~