On Freitag, 10. Juli 2020 19:30:09 CEST Florian Weimer via Gcc wrote: > glibc (or an alternative loader implementation) would search for > libraries starting at level D, going back to level A, and finally the > baseline implementation in the default library location. > > I expect that some distributions will also use these levels to set a > baseline for the entire distribution (i.e., everything would be built to > level A or maybe even level C), and these libraries would then be > installed in the default location. > > I'll be glad if I can get any feedback on this proposal. I plan to turn > it into a merge request for the x86-64 psABI document eventually. > Sounds good, though if I could dream I would also love a partial replacement option. So that you could have a generic x86-64 binary that only had some AVX2 optimized replacement functions in a supplementary library.
Perhaps implemented by marked the library as a partial replacement, so the dynamic linker would also load the base or lower libraries except for functions already resolved. You could also add a level E for the AVX512 instructions in ice lake and above. The VBMI1/2 instructions would likely be useful for autovectorization in GCC. 'Allan