Hi, zimoun <zimon.touto...@gmail.com> skribis:
> On Wed, 24 Nov 2021 at 13:10, Ricardo Wurmus <rek...@elephly.net> wrote: > >> The build phases that patch out these features would have to check >> for that build system option, much like they check the TESTS? >> option before attempting to run tests. > > Then it could be a transformation. The idea sounds good to me. I’ve been working on it last week with my HPC hat on. To be clear, I think in may cases, passing ‘-march’ like you suggest is the wrong approach; instead software should use (and usually does use) function multi-versioning: https://hpc.guix.info/blog/2018/01/pre-built-binaries-vs-performance/ I found one case though where this is not possible: C++ header-only libraries such as Eigen contain hand-optimized vectorized routines, selected at build time, but we end up compiling Eigen users as the x86_64/AArch64 baseline, which is a waste. (If you do know of other problematic cases, I’m interested in taking a look!) My solution to that is “package multi-versioning” via a transformation option. Hopefully I’ll submit preliminary patches within a week or so! Thanks, Ludo’.
