llvm: ability to specify target cpu and features

[steve-numeus]

To an extent, this addresses issues #27 and #12.

model = lleaves.Model(model_file=model_str_filename)
model.compile(
    cache=lleaves_cache_filename,
    target_cpu='',                                   # do not target a specific arch type
    target_cpu_features='+64bit,+avx,+avx2,+sse4.1', # enable these flags
)

per create_target_machine, this will create a compilation target which does not target a specific cpu, and enables avx, avx2 and sse4.1 instruction sets

[siboehm]

This is good stuff, thanks! Happy to merge if the tests pass, I'll try to do another release once it goes in

[steve-numeus]

Thanks for merging Simon!

Does this mean it's automatically available in pypi as a new release or does that have to happen separately?

[siboehm]

No not yet, I need to make a new release for that to happen. I'll try to do it over the next few days

[siboehm]

actually I just gave it a shot, either there'll be a new release on PyPI in 30min or I'll try again later

[steve-numeus]

thanks! :)