[Bug tree-optimization/69292] [graphite] ICE with -floop-nest-optimize

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69292

--- Comment #3 from vries at gcc dot gnu.org ---
After isl code generation, the first BB is bb 28:
...
  <bb 28>:
  if (1 != 0)
    goto <bb 30>;
  else
    goto <bb 2>;

  <bb 30>:

  <bb 33>:
  _48 = _8 > 0;
  if (_48 != 0)
    goto <bb 40>;
  else
    goto <bb 36>;
...

The ICE during update_ssa happens while updating stmt '_48 = _8 > 0' because it
cannot find a reaching def for _8.