[Bug tree-optimization/56933] [4.9 Regression] Vectorizer missing read-write dependency for interleaved accesses

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56933



--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> 2013-04-15 
11:18:43 UTC ---

/* { dg-do run } */



extern void abort (void);

void __attribute__((noinline,noclone))

foo (double *b, double *d, double *f)

{

  int i;

  for (i = 0; i < 1024; i++)

    {

      d[2*i] = 2. * d[2*i];

      d[2*i+1] = 4. * d[2*i+1];

      b[i] = d[2*i] - 1.;

      f[i] = d[2*i+1] + 2.;

    }

}

int main()

{

  double b[1024], d[2*1024], f[1024];

  int i;

  for (i = 0; i < 2*1024; i++)

    d[i] = 1.;

  foo (b, d, f);

  for (i = 0; i < 1024; i+= 2)

    {

      if (d[2*i] != 2.)

        abort ();

      if (d[2*i+1] != 4.)

        abort ();

    }

  for (i = 0; i < 1024; i++)

    {

      if (b[i] != 1.)

        abort ();

      if (f[i] != 6.)

        abort ();

    }

  return 0;

}



/* { dg-final { cleanup-tree-dump "vect" } } */