On Tue, 17 Jan 2012 09:20:43 +0100, Manu <turkey...@gmail.com> wrote:
On 17 January 2012 05:55, bearophile <bearophileh...@lycos.com> wrote:
Walter:
> But don't worry, I'm not planning on working on that at the moment :-)
Until better optimizations are implemented, I see a "simple"
optimization
for vector ops. When the compiler knows an arrays are very small it
unrolls
the operation in-place:
int n = 5;
auto a = new int[n];
auto b = new int[n];
a[] += b[];
==>
int n = 5;
auto a = new int[n]; // a and b are dynamic arrays,
auto b = new int[n]; // but their length is easy to find at compile-time
a[0] += b[0];
a[1] += b[1];
a[2] += b[2];
a[3] += b[4];
a[5] += b[5];
If this doesn't already exist, I think it's quite important. I was
thinking
about needing to repeatedly specialise a template last night for a bunch
of
short lengths of arrays, for this exact reason.
Unrolling short loops must be one of the most trivial and worthwhile
optimisations...
If the compiler knows it's a compile time constant
thus you could use a static foreach.
