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Subject: [Bug libstdc++/107468] std::from_chars doesn't always round to
 nearest
Date: Fri, 10 Feb 2023 17:46:54 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D107468

--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-12 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:0061c84d2d85ca4c2ceca6116937f2d1fab6e10a

commit r12-9154-g0061c84d2d85ca4c2ceca6116937f2d1fab6e10a
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Mon Nov 7 15:17:21 2022 +0100

    libstdc++: Update from latest fast_float [PR107468]

    The following patch partially updates from fast_float trunk.
    That way it gets fix for the incorrect rounding case,
    PR107468 aka https://github.com/fastfloat/fast_float/issues/149
    Using std::fegetround showed in benchmarks too slow, so instead of
    doing that the patch limits the fast path where it uses floating
    point multiplication rather than integral to cases where we can
    prove there will be no rounding (the multiplication will be exact, not
    just that the two multiplication or division operation arguments are
    exactly representable).

    2022-11-07  Jakub Jelinek  <jakub@redhat.com>

            PR libstdc++/107468
            * src/c++17/fast_float/fast_float.h: Partial merge from fast_fl=
oat
            662497742fea7055f0e0ee27e5a7ddc382c2c38e commit.
            * testsuite/20_util/from_chars/pr107468.cc: New test.

    (cherry picked from commit cb0ceeaee9e041aaac3edd089b07b439621d0f29)=