This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: [PATCH][Aarch64] Add vectorized mersenne twister
- From: Ulrich Drepper <drepper dot fsp at gmail dot com>
- To: James Greenhalgh <james dot greenhalgh at arm dot com>
- Cc: Jonathan Wakely <jwakely at redhat dot com>, Michael Collison <Michael dot Collison at arm dot com>, "libstdc++ at gcc dot gnu dot org" <libstdc++ at gcc dot gnu dot org>, nd <nd at arm dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>, richard dot earnshaw at arm dot com, ramana dot radhakrishnan at arm dot com, kyrtka01 at arm dot com, Nick Clifton <nickc at redhat dot com>
- Date: Tue, 6 Jun 2017 13:25:18 +0200
- Subject: Re: [PATCH][Aarch64] Add vectorized mersenne twister
- Authentication-results: sourceware.org; auth=none
- References: <20170602181317.GJ12306@redhat.com> <20170606100727.GA31597@arm.com>
On Tue, Jun 6, 2017 at 12:07 PM, James Greenhalgh
<james.greenhalgh@arm.com> wrote:
> We're a good number of years late to do that without causing some pain.
Well, it's pain for those who deserve it. Who thought it to be a
smart idea to pollute the global namespace?
It's a one-time deal.
> So we have a few solutions to choose from, each of which invokes a trade-off:
>
> 1 Use the current names and pollute the namespace.
IMO unacceptable.
> 2 Use the GCC internal __builtin_aarch64* names and tie libstdc++ to GCC
> internals.
Maybe.
> 3 Define a new set of namespace-clean names and complicate the Neon
> intrinsic interface while we migrate old users to new names.
See Jonathan's proposal. I never suggested that those who don't care
about namespace pollution would have to change their code. Add
appropriate aliases.
There is perhaps number 4:
- use the x86-64 intrinsics which you map to aarch64 intrinsics.
Isn't this compatibility layer planned anyway? I don't know whether
everything maps 1-to-1 and you don't lose performance but you could
this way use the arch-specific code I wrote a long time ago for
x86-64.