[Bug tree-optimization/77318] [7 regression] FAIL: gfortran.dg/graphite/pr68279.f90 -O (internal compiler error)

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77318

--- Comment #6 from Tom de Vries <vries at gcc dot gnu.org> ---
In extract_affine_chrec we have:
...
  unsigned pos = sese_loop_depth (s->scop_info->region, get_chrec_loop (e)) -
1;
  isl_aff *loop = isl_aff_set_coefficient_si
    (isl_aff_zero_on_domain (ls), isl_dim_in, pos, 1);
...

The immediate cause of the ICE is that sese_loop_depth returns 0, so pos ends
up with value UINT_MAX. This causes the out-of-bounds error during the call to
isl_aff_set_coefficient_si.