GCC 11+ on Intel CI runners (Skylake-X, Ice Lake, Sapphire Rapids)
emits AVX-512/AVX10 instructions for std::string / memcpy inlining
that crash with SIGILL on AMD EPYC and older Intel without those
extensions. Root cause: libstdc++ is statically linked into the
binary, so the build host's instruction set becomes a hard runtime
requirement.
The CI binary crashed immediately on DNS2/DNS3 (AMD EPYC Milan) with:
traps: trianglesd[...] trap invalid opcode ip:...e432 error:0
in trianglesd[...+af3000]
Disassembly of the crash site (file offset 0x15b432):
62 f1 7f 08 6f 41 ff vmovdqu8 -0x10(%rcx), %xmm0
This is an AVX10/AVX-512 instruction emitted inside
std::basic_string::basic_string (statically linked libstdc++).
Fix: -march=x86-64-v2 -mtune=generic for all Linux x86_64 builds.
v2 baseline (SSE4.2 + POPCNT + CMPXCHG16B) is from 2009 Nehalem and
supported on every x86_64 CPU we ship to. Override-able via
-DCMAKE_X86_64_BASELINE=OFF if a CPU-specific build is needed.
sami7777
5635cb5e57