On 21 August 2015 at 10:49, Kagamin via Digitalmars-d <digitalmars-d@puremagic.com> wrote:

On Friday, 21 August 2015 at 01:29:12 UTC, H. S. Teoh wrote:

Have you tried using gdc -O3 (or ldc) to see if there's a big
difference?

How -Os and -march=native change the picture?

There's a paper somewhere about optimisations on Intel processors that says that -O2 produces overall better results than -O3 (I'll have to dig it out).

In any case, -Ofast may give you better benchmark results because it permits skipping corners for IEEE and other standards.

Also, -march=native is cheating, as you'll have the most unportable binary created from it. ;-)