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Re: Question about mem_set_list in propagate_block_info
On Wed, 2003-06-04 at 14:46, Toon Moene wrote:
> Richard Henderson wrote:
>
> > On Wed, Jun 04, 2003 at 12:25:05AM -0400, Diego Novillo wrote:
> >
> >>Wait, that doesn't follow. You can have different alias set numbers
> >>that are conflicting.
> >
> > Oh, yes, so you can.
> >
> > I still bet his source is wrong.
>
> Huh ? What am I missing ? What's the use of alias sets, then ?
>
Alias sets are organized in a tree hierarchy (see the comments at the
start of alias.c).
When you call alias_sets_conflict_p() with two alias set numbers, it
traverses this tree trying to reach one alias set node from the other.
If it finds a path, then one of the alias is a subset of the other,
meaning that the two alias sets conflict.
Diego.