[Bug rtl-optimization/63804] [5 Regression] ice in find_oldest_value_reg with -g -O2

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63804

Markus Trippelsdorf <trippels at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |trippels at gcc dot gnu.org

--- Comment #3 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
Somewhat reduced:

markus@x4 tmp % cat bug169.c
struct brw_context
{
  int gen;
} e;
enum brw_reg_type
{
  B
};
struct brw_reg
{
  enum brw_reg_type type : 1;
  int nr : 1;
  struct
  {
    unsigned ud;
  } dw1;
} fn1 ();
struct brw_reg a, c;
long b, d;
int
fn2 (struct brw_reg p2, unsigned p3)
{
  struct brw_reg f, g, h, l = g = p2, m, n = m;
  struct brw_context i = e;
  unsigned j;
  int k;
  if (i.gen)
    p3 = 0;
  p2 = g;
  if (b)
    j = k = 0;
  else
    j = k = 2;
  fn3 ();
  l.type = 0;
  c = a;
  fn4 (p2, 0);
  m = fn1 (0, 0, 0, 0, 0, 0);
  n.dw1.ud = p3;
  f = n;
  h = f;
  d = fn5 (p2.nr);
  fn4 (0, 0, f);
  if (i.gen)
    fn6 (p2, j, k);
}