https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77776
--- Comment #8 from emsr at gcc dot gnu.org --- (In reply to Matthias Kretz from comment #6) > > How precise is hypot supposed to be? I know it is supposed to try and avoid > > spurious overflow/underflow, but I am not convinced that it should aim for > > correct rounding. > > That's a good question for all of <cmath> / <math.h>. Any normative wording > on that question would be (welcome) news to me. AFAIK precision is left > completely as QoI. So, except for the Annex F requirements (which we can > drop with -ffast-math), let's implement all of <cmath> as `return 0;`. ;-) > It looks like C is trying to incorporate ISO/IEC TS 18661-1 Floating-point extensions for C — Part 1: Binary floating-point arithmetic, etc. This adds a lot of rounding control but it looks like correcly rounded transcendentals are still merely a recommendation.
