Re: Does ARMEL toolchain include NEON support?
On Wed, Feb 27, 2019 at 5:46 PM Steve McIntyre <steve@einval.com> wrote:
>
> ...
> >The problem is, I don't know what the output of or 'g++ -dumpmachine'
> >or 'uname -m' are, so I am not sure if we are misdetecting IS_ARM32 or
> >IS_NEON .
>
> So, I've got to ask - what hardware are you likely targeting here
> where it matters to build stuff for armel yet also use NEON if it's
> available? Most people with hardware that *can* do NEON should be
> using armhf, surely?
Yeah, I know what you are saying.
The problem in practice with mainstream compilers is (1) ARM and the
ACLE defines are a mess, (2) -march=native does not work like on i686
or x86_64, and (3) RTFM does not work.
For a regular user who wants to use Debian on ARM we need to figure
out how to build to the least capable machine (like ARMv5 or ARMv6)
while making more capable features (like NEON) available.
User's don't want to RTFM to figure out what compiler switches to use.
They just want things to work. The compilers don't make it any easier
because -march=native does not work on ARM.
So the use case we target is, user want the most from their hardware
without reading the manual to configure properly. That means we have
to go through extra gyrations when building.
(I know we bring it on ourselves. We could easily say fuck it - the
user did not bother to read a man page so its the user's problem. But
I'm in the camp that common cases should just work for folks. Folks
should not need to read a manual to make the common case work).
Jeff
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