Re: Using the GNU GMP Library for Bignums in Emacs

[Paul Eggert]

On 07/18/2018 08:55 AM, Eli Zaretskii wrote:
> Wouldn't calling this upon every float comparison yield a
> non-negligible run-time penalty?  Maybe we should use 'isnan' instead?

No, it's actually faster (at least on x86-64), since it uses a single 
64-bit integer comparison rather than up to three 64-bit floating-point 
comparisons. (The for-loop in question is unrolled into a single 
execution of its body, among other things.)

isnan would slow us down here, since the code does not need to differ 
for NaNs versus non-NaNs.