[patch][graphite] Fix flags set by split_block

[Zdenek Dvorak]

Hi,

> > The following bug occurs at least 7 times in spec2k6:
> > 
> > 959.c:28: error: edge from 17 to 57 should be marked irreducible
> > 959.c:28: error: basic block 57 should be marked irreducible
> > 959.c:28: error: edge from 34 to 53 should be marked irreducible
> > 959.c:28: error: basic block 53 should be marked irreducible
> > 
> > split_block_after_labels does not correctly update the flags for the
> > edges and bbs it creates.  Is this patch correct, or should these
> > flags be set by split_block instead?
> 
> I think split_block should do this instead (after all, split_edge
> does).

yes, it should,

Zdenek