[LLVMdev] i1 Values

[dag at cray.com]

I've been debugging some strange happenings over here and I put an
assert in APInt to catch what I think is the source of the problem:

  int64_t getSExtValue() const {
    // An i1 -1 is unrepresentable.
    assert(BitWidth != 1 && "Signed i1 value is not representable!");

To me an i1 -1 makes no sense whatsoever.  It is not representable in
twos-complement form.  It cannot be distinguished from unsigned i1 1.

It turns out this assert triggers all over the place.  Before I dive
into this rat hole I'd like to confirm with others my sense that we
shouldn't be creating i1 -1 values.  Is there some legitimate reason to
do so?

                             -David