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

[Paul Eggert]

On 7/2/20 11:01 AM, Mattias Engdegård wrote:
> If we want to make allowance for capricious x87 rounding, what about 
> rewriting it to accept integral floats in the ±2^53 range, as well as any 
> integer? This is what it might look like:

Another plausible option would be for Emacs to drop support for x87 rounding, in
the interest of portability. All Apple Intel machines have had SSE2, Microsoft
has been requiring SSE2 by default since MSVC 2012, and it's easy enough to do
the same with GCC and clang.

We'd be in good company as lots of other software packages have dropped support
for non-SSE2 machines, including Cygwin, Java, OpenOffice, PostgreSQL, Python,
QEMU, Thunderbird, VirtualBox; see 
<http://matejhorvat.si/en/unfiled/nosse2.htm>.