boost::python::def_visitor alignment / padding crash.

From: Janek Kozicki (janek.listy.mailowe_at_[hidden])
Date: 2019-12-20 23:14:56

I have discovered an alignment related bug in boost::python::def_visitor

For a very detailed description see https://gitlab.com/libeigen/eigen/issues/1795

* a minimal failing example:
  https://gitlab.com/cosurgi/minieigen-real/blob/minimalFailingExample/src/minimal-failing-float128.cpp

* and the failing CI pipeline:
  https://gitlab.com/cosurgi/minieigen-real/pipelines/104745741

Initially I thought that it was related with libeigen. But it
turns out that it crashes even without libeigen, when just using
boost::multiprecision::float128.

The code crashes with g++ 8.3.0 and works with g++ 9.2.1
boost version 1.67 is used there.

should I open an issue on boost github?

best regards
-- 
# Janek Kozicki                              http://janek.kozicki.pl/