RE: Fwd: Re: Branchless implementation for literal case – is it worth it?

Simon Peyton Jones simonpj at microsoft.com
Mon Apr 20 19:29:34 UTC 2015


| > If the code is already there and some architectures can profit of it,
| > especially in inner loops - why not just make it an optimisation flag?
| 
| Without even one good example where it is an improvement, this does not
| make sense. And even with an example: It degrades performance in other
| cases, so a module-wide flag would probably not cut it.

Moreover code complexity in the compiler carries a real cost. Don't underestimate it!

Simon


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