[Bug c++/69763] New: _Alignof(double) in C gives different results from alignof(double) in C++

[richard-gccbugzilla at metafoo dot co.uk]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69763

            Bug ID: 69763
           Summary: _Alignof(double) in C gives different results from
                    alignof(double) in C++
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: richard-gccbugzilla at metafoo dot co.uk
  Target Milestone: ---

See also bug 52023.

On i386, according to GCC we have _Alignof(double) == 4, but according to G++
we have alignof(double) == 8. This makes no sense, as the same words are used
to specify the semantics in both languages, and this creates a gratuitous
incompatibility between GCC's C and C++ modes.