x86-64-v3
-march=x86-64-v3implies-mtune=generic:
gcc -march=x86-64-v3 -Q --help=target | grep -- '-mtune='- Use 
-with-gcc-arch=x86-64-v3forislandlibffiwhich passesmarchonly (withoutmtune), otherwiseconfigurewill guess the wrong architecture; it detects the native architecture insteadhaswelloramdfam10: 
checking whether C compiler accepts -march=x86-64-v3... yeschecking for gcc architecture flag... -march=x86-64-v3checking whether C compiler accepts  -O3 -fomit-frame-pointer -fstrict-aliasing -ffast-math -march=x86-64-v3... yes- Verify 
x86-64-v3target build withqemu; will not work without passingcpuashost 
References
Section titled “References”- https://discourse.nixos.org/t/pre-rfc-gradual-transition-of-nixos-x86-64-baseline-to-x86-64-v3-with-an-intermediate-step-to-x86-64-v2/35924
 - https://fedoraproject.org/wiki/Changes/Optimized_Binaries_for_the_AMD64_Architecture
 - https://github.com/glaucuslinux/rad/commit/4d978149e5c82ee7d5f4370c97e88e79eb644fd3
 - https://github.com/NixOS/nixpkgs/issues/63708
 - https://github.com/NixOS/nixpkgs/pull/202526
 - https://lwn.net/Articles/1001819/
 - https://sunnyflunk.github.io/2023/01/15/x86-64-v3-Mixed-Bag-of-Performance.html
 - https://www.gentoo.org/news/2024/02/04/x86-64-v3.html
 - https://www.phoronix.com/news/openSUSE-Tumbleweed-x86-64-v2