[tree-ssa] alias analysis

[Diego Novillo]

On Wed, 2003-02-12 at 02:17, Daniel Berlin wrote:

> On a random note, do either of you plan on making calls to may_alias_p 
> from outside of tree-dfa.c anymore?
> 
Yes, of course.  I keep wondering why you removed the call to PTA from
tree-dfa.c.  Ultimately I want to be able to use PTA.  The only reason
why we have a type-based analyzer was because we don't yet have a fully
working PTA one.

> I had moved the freeing of PTA memory to SSA deletion time when Diego 
> was doing alias tags, and using may_alias_p in tree-ssa.c, but if it's 
> not going to be called during SSA building anymore, i'll move the 
> freeing of PTA memory back to where it used to be.
>
Please put it back.  I thought I had neatly separated what we do when
-ftree-points-to is given and when it's not.  I don't know why you
removed it.

If it's because tree-dfa.c doesn't use it properly, let's fix that.  I
want to be able to do both.  Type-based should be *very* fast and rather
stupid.  PTA can be a bit slower (not necessarily, only if it wants to
be), but more precise.


Diego.