On 10/18/18 6:15 PM, Joseph Mingrone wrote:
> Is it still helpful for me to investigate what GCALIGNED_STRUCT expands to?  If so, could elaborate on how I can get this?

To get the expansion (but see below first), put the following into a 
file src/t.c:

#include <config.h>
#include <lisp.h>
"GCALIGNED_STRUCT" GCALIGNED_STRUCT

and then run 'cd src; cc -E -I. -I../lib t.c | tail -n1'. You probably 
need to adjust that command line to match the way you're building Emacs. 
My output with current master on Fedora x86-64 is:

"GCALIGNED_STRUCT" __attribute__ ((aligned (8)))


However, in thinking about this some more I do see a problem that could 
explain your symptoms, a problem that resulted from a merge from 
emacs-26 that collided with changes in the master without Git (or me) 
noticing the collision. I installed the attached patch into master to 
fix it. Please try this patch first, and we can worry about 
GCALIGNED_STRUCT only if this patch does not fix things for you.