Trying to use the value-range interface and functions I am running into that ICE when using invert().
From what the sources suggest, invert() computes the complement of the current set (the union of finitely many intervals). For example, when I have a range of [-128, -1] for int8_t, invert() runs into that ICE because that interval is undefined or varying. Take for example, this code that wants to take the complement of the complete interval (with respect to the complete interval given by uint8_t): tree t = unsigned_intQI_type_node; int n_bits = TYPE_PRECISION (t); int_range<2, false /*resizable*/ > j(t); // j is undefined(?), thus set its bounds to the entire range. j.set (t, wi::to_wide (j.lbound()), wi::to_wide (j.ubound())); j.invert(); <built-in>: internal compiler error: in invert, at value-range.cc:2165 0 This should just return the empty set; no? And vice versa, the complement of the empty set (with respect to the whole interval) should be the whole interval provided by t, no? If I understand correctly, the int_range<> implementation does not implement a semi-group, and there are sets / intervals that are not allowed, like the empty set or intervals that touch a boundary. Does this mean that I have to test and special-case all these cases and do them by hand? Are there more invalid / disallowed intervals? So I guess it is simpler when I write my own interval arithmetic that handles these cases and behaves like a semi group. As there will be at most 3 sub-intervals, that's the way to go...? Isn't there a knob to tell that complement is with respect to the range as provided by type(), and not w.r.t. the integers? Johann
