[Bug libstdc++/90611] Generating a bad sse instruction for 32 bit

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90611

--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Oh, I forgot that I already implemented another option in
__gnu_cxx::malloc_allocator, which is to check the alignment of the returned
memory and only fail if it isn't suitably aligned:

      pointer
      allocate(size_type __n, const void* = 0)
      {
        if (__n > this->max_size())
          std::__throw_bad_alloc();

        pointer __ret = 0;
#if __cpp_aligned_new
#if __cplusplus > 201402L && _GLIBCXX_HAVE_ALIGNED_ALLOC
        if (alignof(_Tp) > alignof(std::max_align_t))
          {
            __ret = static_cast<_Tp*>(::aligned_alloc(alignof(_Tp),
                                                      __n * sizeof(_Tp)));
          }
#else
# define _GLIBCXX_CHECK_MALLOC_RESULT
#endif
#endif
        if (!__ret)
          __ret = static_cast<_Tp*>(std::malloc(__n * sizeof(_Tp)));
        if (!__ret)
          std::__throw_bad_alloc();
#ifdef _GLIBCXX_CHECK_MALLOC_RESULT
#undef _GLIBCXX_CHECK_MALLOC_RESULT
          if (reinterpret_cast<std::size_t>(__ret) % alignof(_Tp))
            {
              // Memory returned by malloc is not suitably aligned for _Tp.
              deallocate(__ret, __n);
              std::__throw_bad_alloc();
            }
#endif
        return __ret;
      }

This means it might work sometimes, if you get lucky with malloc's return
value.