message: add fast-math support for fneg
diff: @@ -885,11 +885,8 @@ StateValue UnaryOp::toSMT(State &s) const {
  return { move(var), true };
  }
  case FNeg:
  - // TODO
  - if (!fmath.isNone())
  - return {};
  - fn = [](auto v, auto np) -> StateValue {
  - return { v.fneg(), expr(np) };
  + fn = [&](auto v, auto np) -> StateValue {
  + return fm_poison(s, v, np, [](expr &v){ return v.fneg(); }, fmath, false);
  };
  break;
  case FFS:
  