Ok, so indeed I got NO_REG for g->nodes[n2].reg

print g->nodes[n2].reg
$1 =3D 4294967295

than I set breakpoint at end of ra_simplify (it gets called just once before
the crash)

Breakpoint 1, ra_simplify (g=3D0x80c2058)
    at ../../src/mesa/program/register_allocate.c:491
491    }
(gdb) print g->count
$2 =3D 3

print g->nodes[0]
$3 =3D {adjacency =3D 0x81b8968, adjacency_list =3D 0x80c1658,=20
  adjacency_list_size =3D 4, adjacency_count =3D 3, class =3D 0, reg =3D 42=
94967295,=20
  in_stack =3D false, q_total =3D 4294967295, spill_cost =3D 0}

print g->nodes[1]
$4 =3D {adjacency =3D 0x81b3d18, adjacency_list =3D 0x80c1b58,=20
  adjacency_list_size =3D 4, adjacency_count =3D 3, class =3D 2, reg =3D 42=
94967295,=20
  in_stack =3D true, q_total =3D 2, spill_cost =3D 0}

print g->nodes[2]
$5 =3D {adjacency =3D 0x81c0328, adjacency_list =3D 0x80c18d8,=20
  adjacency_list_size =3D 4, adjacency_count =3D 3, class =3D 3, reg =3D 42=
94967295,=20
  in_stack =3D true, q_total =3D 4, spill_cost =3D 0}