Comment 6 for bug 1395019

Created attachment 31350
gcc49-pr59358.patch

Untested fix. The problem is with:
Meeting
  [-INF, y_5(D) + -1] EQUIVALENCES: { z_4 } (1 elements)
and
  [-INF(OVF), 30]
to
  [-INF(OVF), y_5(D) + -1] EQUIVALENCES: { } (0 elements)
Found new range for z_1: [-INF(OVF), y_5(D) + -1]

Because one of the maximum is symbolic, y_5(D) + -1 and 30 are effectively uncomparable (operand_less_p doesn't return 1 for either order of those).
Apparently union_ranges implicitly assumes certain ordering based on earlier tests, like from
  else if ((maxeq || operand_less_p (vr1max, *vr0max) == 1)
           && (mineq || operand_less_p (*vr0min, vr1min) == 1))
being false it assumes that if
  else if ((operand_less_p (vr1min, *vr0max) == 1
            || operand_equal_p (vr1min, *vr0max, 0))
           && operand_less_p (*vr0min, vr1min) == 1
is true then operand_less_p (*vr0max, vr1max) == 1, but that is not guaranteed.