https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109008
--- Comment #45 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Created attachment 54623 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54623&action=edit gcc13-pr109008-3.patch Further incremental patch to do the .5ulp widening rather than 1ulp if not -frounding-math and not for IBM double double. So far I've tested the + and - 300000 tests, still no errors (so conservatively correct) and: 1 0 50 1 1 11 1 11 1 1 1 13 1 1 16 1 1 25 1 1 28 1 1 3 1 1 36 1 1 4 1 1 40 1 19 1 1 39 1 1 50 0 2 1 17 2 1 2 2 1 32 2 1 7 2 2 1 2 5 1 3 3 1 3 4 1 38 50 1 56 1 50 71 1 0 78 0 1 160 50 50 13173 0 0 130096 -1 -1 154232 1 1 so significantly better than the 1ulp version, over 50% of cases are 1ulp away in each direction, over 43% of other cases have really empty range, over 4% exact and rest is noise. Let me finish * and / testing. For the forward op, we'd need to do something like in the #c30 patch, which was ugly. And regarding !MODE_HAS_INFINITIES, the min/max values really act there like infinities, so I think we should just detect that case and use infinities in the widened range even when the mode doesn't have them. But, I'm afraid I don't know how to test that...
