[Bug tree-optimization/89509] New: restrict doesnt work with subfield accesses

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89509

            Bug ID: 89509
           Summary: restrict doesnt work with subfield accesses
           Product: gcc
           Version: 9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rguenth at gcc dot gnu.org
  Target Milestone: ---

struct S { int i; void *p; int j; };
int
foo (struct S * __restrict p, int *q, int flag)
{
  int *x = &p->j;
  if (flag)
    x = &p->i;
  *q = 1;
  *x = 2;
  return *q;
}

Is not optimized to return 1.  This is the missed-optimization part of
PR89505.