[Bug tree-optimization/68787] fipa-pta to interpret restrict

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68787

--- Comment #5 from vries at gcc dot gnu.org ---
Created attachment 38189
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=38189&action=edit
patch to recompute restrict info after ipa-pta

(In reply to Richard Biener from comment #4)
> One possibility would be to re-run non-IPA PTA just to compute restrict info,
> that is, instead of bailing out when cfun->gimple_df->ipa_pta just not update
> SSA pointer-info but still call compute_dependence_clique.  Requires
> splitting of compute_points_to_sets into the actual compute and SSA
> pointer-info
> update parts.

That sound similar to what I've tried here:
https://gcc.gnu.org/ml/gcc-patches/2015-12/msg01257.html .

Attaching a more minimal version.

But it doesn't affect the testcase, and I'm not sure how it could (perhaps it
will affect another test-case, I'm not sure).

For the listed testcase, after ipa-pta we have:
...
__attribute__((noclone, noinline))
bar (intD.6 * aD.1755, intD.6 * bD.1756)
{
  # PT = nonlocal
  intD.6 * a_2(D) = aD.1755;
  # PT = nonlocal
  intD.6 * b_4(D) = bD.1756;
  intD.6 _6;
  intD.6 _7;
...

There's nothing to take advantage of by trying to reannotate with restrict.