[Bug tree-optimization/116874] New: phiprop should handle more than just `a->t`

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116874

            Bug ID: 116874
           Summary: phiprop should handle more than just `a->t`
           Product: gcc
           Version: 15.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org
  Target Milestone: ---

Take:
```
struct Foo {
  int t;
  int x;
};


int f(struct Foo a, struct Foo b, int c)
{
  struct Foo d;
  struct Foo *l;
  if (c) l = &a; else l = &b;
  d = *l;
  return d.t + d.x;
}
```

Right now phiprop only handles `MEM[x]` but it should handle more, e.g.:
```
  # l_3 = PHI <&a(2), &b(3)>
  d$t_6 = MEM[(const struct Foo &)l_3].t;
  d$x_5 = MEM[(const struct Foo &)l_3].x;
```

I don't know how often this should up though.