[Freepooma-devel] Metaprograms for constant rolling loops

[Richard Guenther]

Hi!

There are a lot of constant rolling loops implemented via
template metaprograms at the moment.  My experience with
current compilers is that they have good enough loop optimizers
to deal with constant rolling loops.  In fact using template
metaprograms for this causes a compile time increase and
(possibly) hinders auto-vectorization and other loop optimizations.
Also it (may) confuse inlining heuristics.

So the question is, are template metaprogram still worth it for
loops like

  for (int i=0; i<3; ++i)
    a[i] = x;

?

What is your experience?

Just to ask before ripping out those from Tiny/ and other places.

Thanks,
Richard.

--
Richard Guenther <richard dot guenther at uni-tuebingen dot de>
WWW: http://www.tat.physik.uni-tuebingen.de/~rguenth/