Testsuite test  gcc.dg/tree-ssa/loop35.c fails for avr target for test3().

This test uses long array index. Tests with int or char index get hoisted as expected.

void test3(unsigned long b)
{
  unsigned i;

  /* And here.  */
  for (i = 0; i < 100; i++)
    {
      arr[b+8].X += i;
      arr[b+9].X += i;
    }
}

Richard Guenther indicates:
> This is because the alias-oracle for store-motion doesn't handle conversions
> to sizetype well in the offset disambiguation.