bug#42147: 28.0.50; pure vs side-effect-free, missing optimizations?

[Mattias Engdegård]

4 juli 2020 kl. 18.33 skrev Stefan Monnier <monnier@iro.umontreal.ca>:

> Is there a way to tell gcc to try and avoid x87's idiosyncrasies without
> being platform-dependent (or at least without imposing SSE2, since
> I still use Emacs on my old Thinkpad X30)?

There is -ffloat-store, which cures the 80 bit intermediary result problem 
while retaining the double-rounding one (which tends to be less common in 
practice). Maybe it is good enough?