On Tuesday, 3 October 2017 at 14:07:39 UTC, SrMordred wrote:
On Tuesday, 3 October 2017 at 13:53:38 UTC, rikki cattermole
wrote:
Be warned, x86 cpu's today are not like they were 10 years
ago. A good portion of a symbol could be full of nop's and it
could end up being faster than the one without them.
Next, compare against ldc, not gdc primarily. Its better
maintained and ugh more inline with dmd (its a bit of a mess,
lets not go there). Of course nothing wrong with doing both.
std.container.* is basically dead. We need to replace it. We
are currently waiting on std.experimental.allocators before
going much more further (also a lot of other no-gc stuff).
Compare (on https://d.godbolt.org/ with "ldc -O3" and "gdc
-O3"):
---
auto test1(int[] arr, int cmp)
{
int[] r;
foreach(v ; arr)
if(v == cmp)r~=v;
return r;
}
import std.container.array;
auto test2(ref Array!int arr, int cmp)
{
Array!int r;
foreach(v ; arr)
if(v == cmp)r.insert(v);
return r;
}
---
With ldc the results are similar.
5k+
And I know, im not into performance comparison yet. But you
know, less code, more cache friendly (and sometimes better
performance).
Well -O3 does not generate cache friendly assembly anyway. For
instance, inlining functions regardless of cost.
I'd take the assembly count with a pinch of salt when you are
using templated code.
Iain
