bug#41321: 27.0.91; Emacs aborts due to invalid pseudovector objects

[Paul Eggert]

On 5/25/20 7:53 AM, Eli Zaretskii wrote:

> why did we move to max_align_t as the alignment requirement?
> AFAIU, GCC enlarged that recently to allow for _Float128 type (at
> least on 32-bit hosts), but do we really need that?

Not on current glibc on any platform that I know, no. I was merely trying to
keep the code portable to platforms where (say) alignof (pthread_cond_t) == 16.
POSIX allows this, and this sort of thing is likely to happen somewhere in the
not-too-distant future, for performance reasons.

> Does the use of max_align_t means that now stack-based Lisp objects
> will need to have 16-byte alignment on 32-bit Windows?

No, because we don't need to GC stack-based objects themselves (the stack will
reclaim them) and the GC find everything they point to (as it scans the stack).