GCC rejects -mno-avx512-4fmaps / -mno-avx512-4vnniw with the dash.
The correct form is -mno-avx5124fmaps / -mno-avx5124vnniw (no dash
between 'avx512' and the sub-feature name). v6.2.0-rc1 failed in CI
with 'unrecognized command-line option' on these two flags; this fixes
the spelling.
v6.1.9 was built on a GitHub Actions EPYC 7763 runner (AVX-512 capable)
and contained 741 vpbroadcastq EVEX instructions in inlined libstdc++
std::string paths. The resulting binary crashed with SIGILL on every
production node: KVM EPYC (DNS2), Ryzen 5 3600 (SAMI-PC), and any
non-x86_64 node.
cmake/AddCompilerFlags.cmake already set -march=x86-64-v2 -mtune=generic
but GCC 11.4 + libstdc++ inlining still autovectorized some paths to
AVX-512. The fix adds an explicit -mno-avx512f -mno-avx512* block
inside CMAKE_X86_64_BASELINE so the build cannot leak AVX-512 regardless
of the build host's capabilities.
Carries forward the v6.1.9 staking-selfheal fix (f69f087) unchanged.
Bump version 6.1.9 -> 6.2.0 to reflect the build-system change.
See references/avx-512-sigill-build-fix.md for the full diagnosis
recipe and the verification steps.
Sami Ahmed