erichkeane added a comment. In D71467#1786188 <https://reviews.llvm.org/D71467#1786188>, @uweigand wrote:
> In D71467#1785943 <https://reviews.llvm.org/D71467#1785943>, @erichkeane > wrote: > > > I did the compare operators that didn't work right, and will do a separate > > patch for the fp-classification type ones: > > f02d6dd6c7afc08f871a623c0411f2d77ed6acf8 > > <https://reviews.llvm.org/rGf02d6dd6c7afc08f871a623c0411f2d77ed6acf8> > > > Thanks! Now I'm getting the correct output for the float test cases as well, > and I've added them to the patch. > > As to fp-classification, I think there is an additional complication here: > according to IEEE and the proposed C2x standard, these builtins should > **never** raise any exception, not even when receiving a signaling NaN as > input. Strictly speaking, this means that they cannot possibly be > implemented in terms of any comparison operation. > > Now, on SystemZ (and many other platforms, I think) there are in fact > specialized instructions that will implement the required semantics without > raising any exceptions, but there seems to be no way to represent those at > the LLVM IR level. We'll probably need some extensions here (some new > IR-level builtins?) ... > > (But I'd say that problem is unrelated to this patch, so I'd prefer to > decouple that problem from the question of whether **this** patch is the > right solution for comparisons.) __builtin_fpclassify/isfinite/isinf/isinf_sign/isnan/isnormal/signbit are all implemented the same as the OTHER ones, except there is a strange fixup step in SEMA that removes the float->double cast. It is IMO the wrong way to do it. I don't think it would modify the IR at all or the AST, but I'm also working on removing that hack (which is what I meant by the fp-classification type ones). I hope the work I've done already is sufficient to unblock this patch. CHANGES SINCE LAST ACTION https://reviews.llvm.org/D71467/new/ https://reviews.llvm.org/D71467 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
