[Bug middle-end/38236] New: [4.4 Regression] SMT aliases incomplete

[rguenth at gcc dot gnu dot org]

struct X { int i; };

int __attribute__((noinline))
foo (struct X *p, int *q, int a, int b)
{
  struct X x, y;
  if (a)
    p = &x;
  if (b)
    q = &x.i;
  else
    q = &y.i;
  *q = 1;
  return p->i;
}
extern void abort (void);
int main()
{
  if (foo((void *)0, (void *)0, 1, 1) != 1)
    abort ();
  return 0;
}

is miscompiled (the store to *q is deleted as unused) because the SMT used
for *p misses the x and y aliases as x and y are neither directly stored
nor is their SMT (but only the aliasing SMT for int).


-- 
           Summary: [4.4 Regression] SMT aliases incomplete
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Keywords: wrong-code, alias
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: rguenth at gcc dot gnu dot org
OtherBugsDependingO 38151
             nThis:


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38236