quick question about port:llvm-xy +polly

[René J.V. Bertin]

Hello,

Is it enough to install port:llvm-4.0 +polly to get the (potential) benefits of that optimiser or do I have to rebuild port:clang-4.0 to make it aware of the availability?

BTW, are there any real-world benefits? I haven't had any luck finding any answer to that question that isn't in the form of some kind of specialist research paper or technical report.

Thanks,
R.