[Bug libstdc++/104859] [12 regression] liibg++ fails during bootstrap

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104859

--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Patrick Palka <ppalka@gcc.gnu.org>:

https://gcc.gnu.org/g:65857caee8ccfac5007a9fd0e5f18cce5e5fe934

commit r12-7571-g65857caee8ccfac5007a9fd0e5f18cce5e5fe934
Author: Patrick Palka <ppalka@redhat.com>
Date:   Wed Mar 9 18:48:52 2022 -0500

    libstdc++: Avoid implicit narrowing from uint128_t [PR104859]

    We need to be explicit about narrowing conversions from uint128_t since,
    on targets that lack __int128, this type is defined as an integer-class
    type that is only _explicitly_ convertible to the builtin integer types.
    This issue was latent until r12-7563-ge32869a17b788b made the frontend
    correctly reject explicit conversion functions during (dependent)
    copy-initialization.

            PR libstdc++/104859

    libstdc++-v3/ChangeLog:

            * src/c++17/floating_to_chars.cc (__floating_to_chars_hex):
            Be explicit when narrowing the shifted effective_mantissa,
            since it may have an integer-class type.