Re: Bug in ra-colorize.c:merge_moves?

[Denis Chertykov <denisc at overta dot ru>]

Daniel Berlin <dberlin at dberlin dot org> writes:

> On Monday, March 3, 2003, at 02:59  PM, Michael Matz wrote:
> 
> > Hi,
> >
> > On Mon, 3 Mar 2003, Daniel Berlin wrote:
> >
> >> new-regalloc-branch isn't very good compile-time wise.
> >> For instance, we can't ever color in one pass anymore (it pretends
> >> something has changed, even if nothing has, so the minimum number of
> >> passes is 2).
> >
> > Oh, really?  That should obviously not happen.  Do you have a
> > testcase, so
> > I can fix that?
> 
> You probably don't need a testcase, since it's obvious from looking at
> the code itself.  You just probably didn't notice when it happened
> (it's a one line problem, hard to see).
> 
> In one_pass, we have:
> 
>   else if (ra_pass == 1)
>      {
>        if (death_insns_max_uid < get_max_uid ())
>          {
>            sbitmap_free (insns_with_deaths);
>            insns_with_deaths = sbitmap_alloc (get_max_uid ());
>            sbitmap_ones (insns_with_deaths);
>            death_insns_max_uid = get_max_uid ();
>          }
>        last_changed_insns = ra_modified_insns;
>        detect_web_parts_to_rebuild ();
>        last_changed_insns = NULL;
>        something_spilled = 1;
>        last_max_uid = get_max_uid ();
>      }
> 
> Note that it's setting something_spilled to 1 unconditionally on the
> first pass (which automatically means we will do another pass, since
> we return something spilled as the return value of one_pass, and the
> calling code is "changed = one_pass ...").
> This code isn't in the HEAD's ra.c.  IIRC, it was added by Denis on
> 08-Jan-03, in revision 1.1.2.65:
> 1.1.2.65     (denisc   08-Jan-03):       something_spilled = 1;

The previous condition is 'if (!WEBS (SPILLED))'.
Only if we have a webs to spill then we doing this.

Only if we want to spill a web which can't have sigle color.
(May be I'm wrong.)
I'm very interested in testcase. 

Denis.