[Bug libstdc++/125548] piecewise_linear_distribution(nw, xmin, xmax, fw) invokes fw with incorrect values

[cvs-commit at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125548

--- Comment #2 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Tomasz Kaminski <tkami...@gcc.gnu.org>:

https://gcc.gnu.org/g:2cb78d1a0e5bd0d831690296df0bc35128ae009c

commit r17-4535-g2cb78d1a0e5bd0d831690296df0bc35128ae009c
Author: Tomasz KamiÅski <tkami...@redhat.com>
Date:   Wed Sep 9 09:55:18 2026 +0200

    libstdc++: Merge piecewise distributions configuration defines.
[PR82749,PR125548]

    This patch introduces _GLIBCXX_USE_NEW_PIECEWISE_DISTRIBUTIONS that
    replaces a separate _GLIBCXX_USE_OLD_PIECEWISE_DISTRIBUTIONS (value 0)
    and _GLIBCXX_USE_RESULT_TYPE_FOR_PIECEWISE_DENSITIES (value 2).

    This better reflects their behavior, as they were not orthogonal previously
    as defining _GLIBCXX_USE_RESULT_TYPE_FOR_PIECEWISE_DENSITIES hand no effect
    if _GLIBCXX_USE_OLD_PIECEWISE_DISTRIBUTIONS was defined.

    libstdc++-v3/ChangeLog:

            PR libstdc++/82749
            PR libstdc++/125548
            * doc/xml/manual/using.xml
            (_GLIBCXX_USE_OLD_PIECEWISE_DISTRIBUTIONS)
            (_GLIBCXX_USE_RESULT_TYPE_FOR_PIECEWISE_DENSITIES): Replace with...
            (_GLIBCXX_USE_NEW_PIECEWISE_DISTRIBUTIONS): Add entry.
            * doc/html/manual/using_macros.html: Regenrate.
            * include/bits/c++config (_GLIBCXX_USE_NEW_PIECEWISE_DISTRIBUTIONS)
            [__cplusplus >= 201103L]: Define to the value 1 if not already
defined.
            * include/bits/random.h
            (__detail::__piecewise_distributions_storage)
            (__detail::__piecewise_distributions_storage_t): Adjust to depend
            on _GLIBCXX_USE_NEW_PIECEWISE_DISTRIBUTIONS value.
            (piecewise_constant_distribution::_CalcType)
            (piecewise_linear_distribution::_CalcType)
            (piecewise_constant_distribution::param_type::densities)
            (piecewise_linear_distribution::param_type::densities):
            Check for non-zero value of
_GLIBCXX_USE_NEW_PIECEWISE_DISTRIBUTIONS
            instead of defintion of _GLIBCXX_USE_OLD_PIECEWISE_DISTRIBUTIONS
and
            reorder branches.
            * include/bits/random.tcc
            (piecewise_constant_distribution::param_type::param_type)
            (piecewise_constant_distribution::param_type::param_type):
Likewise.
            *
testsuite/26_numerics/random/piecewise_constant_distribution/operators/accessors.cc:
            Replace checks for _GLIBCXX_USE_OLD_PIECEWISE_DISTRIBUTIONS
            _GLIBCXX_USE_RESULT_TYPE_FOR_PIECEWISE_DENSITIES defintions
            with checks of _GLIBCXX_USE_NEW_PIECEWISE_DISTRIBUTIONS values.
            *
testsuite/26_numerics/random/piecewise_linear_distribution/operators/accessors.cc:
            Likewise.
            *
testsuite/26_numerics/random/piecewise_linear_distribution/cons/pr125548.cc:
            Likewise.
            *
testsuite/26_numerics/random/piecewise_constant_distribution/operators/accessors_fallback.cc:
            Replace -D_GLIBCXX_USE_OLD_PIECEWISE_DISTRIBUTIONS with
            -D_GLIBCXX_USE_NEW_PIECEWISE_DISTRIBUTIONS=0.
            *
testsuite/26_numerics/random/piecewise_linear_distribution/operators/accessors_fallback.cc:
            Likewise.
            *
testsuite/26_numerics/random/piecewise_linear_distribution/cons/pr125548_fallback.cc:
            Likewise.
            *
testsuite/26_numerics/random/piecewise_constant_distribution/cons/input_type_fallback_neg.cc:
            Likewise.
            *
testsuite/26_numerics/random/piecewise_linear_distribution/cons/input_type_fallback_neg.cc:
            Likewise.
            *
testsuite/26_numerics/random/piecewise_constant_distribution/operators/accessors_exact.cc:
            Replace -D_GLIBCXX_USE_RESULT_TYPE_FOR_PIECEWISE_DENSITIES with
            -D_GLIBCXX_USE_NEW_PIECEWISE_DISTRIBUTIONS=2.
            *
testsuite/26_numerics/random/piecewise_linear_distribution/operators/accessors_exact.cc:
            Likewise.

    Reviewed-by: Jonathan Wakely <jwak...@redhat.com>