R Compiler Options in the linux (ubuntu) Binaries? AVX?

curiosity question:  I was wondering whether the R binaries and BLAS
libraries for ubuntu linux are compiled using SSE4 and AVX support.
this probably can go a long way towards a unified memory bus GPGPU
substitute.

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Ivo Welch (ivo.welch at gmail.com)
http://www.ivo-welch.info/