food for thought - swift 5 released - bottom types, string interpolation, and stuff.

[jmh530]

On Friday, 12 April 2019 at 10:52:00 UTC, Patrick Schluter wrote:
> [snip]
>
> funny you mention abs(). My current job was enabled because the 
> project leader was impressed with my optimisation skill. The 
> first change I made in the code base (in the Levenshtein 
> routine) was to replace the call to abs() by a macro doing 
> nothing more fancy than "n>0?n:-n". The gain in performance was 
> so massive, it completely floored me at that time. People 
> underestimate the cost of a call, especially into a dynamic 
> library (it is an indirect jump via the GOT), if it is in the 
> hot loop it can be a massive cycle waster.
>

Was this C code (based on the reference to macros)? Could you get 
the same performance boost by pulling abs out into a static 
library?