[Bug libstdc++/88849] New: std::binomial_distribution generates slightly larger values than expected

[heavy.watal at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88849

            Bug ID: 88849
           Summary: std::binomial_distribution generates slightly larger
                    values than expected
           Product: gcc
           Version: 8.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: heavy.watal at gmail dot com
  Target Milestone: ---

Created attachment 45430
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=45430&action=edit
Visualization of the distribution difference

Here is a reproducible example:
https://github.com/heavywatal/scribble/tree/master/cxx/binomial

The sum of 10000 values from std::binomial_distribution(1000, 0.01) was
calculated 1000 times. Those from libstdc++ are slightly larger than expected.

Environment:
macOS 10.14.2
g++-8 -v
Using built-in specs.
COLLECT_GCC=g++-8
COLLECT_LTO_WRAPPER=/usr/local/Cellar/gcc/8.2.0/libexec/gcc/x86_64-apple-darwin18.0.0/8.2.0/lto-wrapper
Target: x86_64-apple-darwin18.0.0
Configured with: ../configure --build=x86_64-apple-darwin18.0.0
--prefix=/usr/local/Cellar/gcc/8.2.0
--libdir=/usr/local/Cellar/gcc/8.2.0/lib/gcc/8
--enable-languages=c,c++,objc,obj-c++,fortran --program-suffix=-8
--with-gmp=/usr/local/opt/gmp --with-mpfr=/usr/local/opt/mpfr
--with-mpc=/usr/local/opt/libmpc --with-isl=/usr/local/opt/isl
--with-system-zlib --enable-checking=release --with-pkgversion='Homebrew GCC
8.2.0' --with-bugurl=https://github.com/Homebrew/homebrew-core/issues
--disable-nls --disable-multilib --with-native-system-header-dir=/usr/include
--with-sysroot=/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk
Thread model: posix
gcc version 8.2.0 (Homebrew GCC 8.2.0)