[Nix-dev] Stdenv compilation times

[Lluís Batlle]

2010/1/18 Eelco Dolstra <e.dolstra at tudelft.nl>:
> BTW, it's not entirely clear whether Graphite is currently all that useful to
> enable in the default GCC build.  I couldn't really find any benchmarks about
> this.  AFAIK the GCC flags that turn on the Graphite optimisations are not
> included in -O2/-O3, so there are probably no packages in Nixpkgs that would
> currently benefit anyway.
I've checked the gcc manual, and I also understand that no
Graphite-related optimization is performed under -O2 or -O3, so the
only way a package can get some benefit from them is with explicit
statement of the optimization flags.
I've been looking for a benchmark showing any improvement involving
the ppl thing in gcc, and I have not found it.
As far as I understand, the few optimizations that can be enabled will
interest mostly people wanting to avoid cache hits in some rare simple
but long loops, and I think that the kind of people having any need of
that, they would have written the loops better themselves before
expecting gcc to support such optimizations.

So I would accept easily having cloog+ppl disabled in the main stdenv gcc.

Regards,
Lluís.