Re: Moving some VRP bits from DOM into tree-vrp

[Diego Novillo <dnovillo at redhat dot com>]

On Mon, Jun 13, 2005 at 05:24:10PM -0600, Jeffrey A Law wrote:

> For better or worse, I've found that DOM is still finding a lot of
> stuff that is being missed by other passes.  So this process isn't
> simply "remove large hunk of DOM code, but instead is going to involve
> improving the other passes so that they're catching most (if not all)
> of the things DOM does.
> 
Yes, I did some experiments a few days ago.  I switched off all
the transformations done by DOM using the VRP records.  It
resulted in almost negligible losses in the amount of jumps
threaded:

cc1-i-files:	-0.21%
DLV:		-0.09%
MICO:		-0.05%
SPEC2000:	-0.96%
TRAMP3D:	-0.05%

Most of the opportunities came from dummy statements created by
DOM.


> *************** vrp_finalize (void)
> *** 3445,3450 ****
> --- 3578,3589 ----
>   
>     substitute_and_fold (single_val_range, true);
>   
> +   /* One could argue all simplifications should be done here
> +      rather than using substitute_and_fold since this code
> +      is going to have to perform a complete walk through the
> +      IL anyway.  */
> +   simplify_using_ranges ();
> + 
>
Why not do this in substitute_and_fold?  It knows about the
ranges and does a full IL scan already.


Diego.