[Bug tree-optimization/87665] [8/9 Regression] gcc HEAD (svn: 265340) breaks elements on resize

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87665
--- Comment #11 from Richard Biener <rguenth at gcc dot gnu.org> ---
C testcase that is miscompiled:

struct X { long x; long y; };

struct X a[1024], b[1024];

void foo ()
{
  for (int i = 0; i < 1024; ++i)
    {
      long tem = a[i].x;
      a[i].x = 0;
      b[i].x = tem;
      b[i].y = a[i].y;
    }
}

int main()
{
  for (int i = 0; i < 1024; ++i)
    a[i].x = i;
  foo ();
  for (int i = 0; i < 1024; ++i)
    if (b[i].x != i)
      __builtin_abort();
  return 0;
}