[Bug c/48885] missed optimization with restrict qualifier?

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=48885

--- Comment #12 from vries at gcc dot gnu.org ---
(In reply to Richard Biener from comment #11)
> I'm testing the above simple fix and amend the comment.

Consider the example with functions f and g I gave in comment 10. Using the
patch from comment 11, I get at ealias:
...
void f(int* __restrict__&, int*) (intD.9 * restrict & restrict pD.2252, intD.9
* p2D.2253)
{
  intD.9 * _3;

  # VUSE <.MEM_1(D)>
  # PT = { D.2265 } (nonlocal)
  _3 = MEM[(intD.9 * restrict &)p_2(D) clique 1 base 1];

  # .MEM_4 = VDEF <.MEM_1(D)>
  MEM[(intD.9 *)_3 clique 1 base 2] = 1;

  # .MEM_6 = VDEF <.MEM_4>
  MEM[(intD.9 *)p2_5(D) clique 1 base 0] = 2;
...

AFAIU, this is incorrect. The two stores can be now disambiguated based on same
clique/different base, but in fact the stores can alias (in fact they do, in
the  "f (gp, gp)" call from g).