You sound like you know what you're talking about. > They never tried, honestly - ICC had plenty of defaults that were targeted at performance above correctnes

You sound like you know what you're talking about. > They never tried, honestly - ICC had plenty of defaults that were targeted at performance above correctness. Is it possible to get ICC level performance out of open source tools? Much of my CPU bound work relates to array signal processing, which, if you can code it right :) lends itself heavily to SIMD branchless pipelines. Plus some scatter gathers on a group of other cores to calculate a sparse crosscorrelation tensor. I would love to be able to get same or better performing code out of clang or gcc, even it it takes 2-4x more work than with ICC...