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Date: Mon, 27 Oct 2003 13:50:21 -0500
From: Andrew Lenharth <andrewl@debian.org>
To: William Chesters <williamc@paneris.org>
Cc: caml-list@inria.fr
Subject: Re: [Caml-list] partial eval question
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References: <004a01c39c2b$819db8f0$1fcf2952@Archimedes> <20031027081453.37b9f6ee.Damien.Pous@ens-lyon.fr> <16285.15401.421786.814601@beertje.william.bogus>
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On Mon, Oct 27, 2003 at 03:39:21PM +0000, William Chesters wrote:
> And that's an improvement over
> 
>     double pow(double x, int n) {
>       double it = 1;
>       while (--n >= 0) it *= x;
>       return it;
>     }
> 
>     double pow3(double x, int n) {
>       return pow(x, 3);
>     }
> 
> in what way exactly?  (If it doesn't work for you, try
> -funroll-all-loops.)

And that's an improvement over

template <int N>
inline double pow (double x) {
  return x * pow<N-1>(x);
}
template<>
inline double pow<0> (double x) {
  return 1.0;
}

in what way exactly?  (If it doesn't work for you, try 
-O2) :)

The C example relies on a fairly smart compiler to 
do interprocedual analysis.  The C++ example 
only requires the inline keywork be honored, and you 
don't need explicit pow3 pow2, you have pow<3> pow<2> 
pow<any constant>.

Gives a bit more control over code generation.

Andrew

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