simd

README

SIMD experiment (Go 1.26+)

This package requires Go 1.26 with GOEXPERIMENT=simd and amd64.

See benchmarks.

CPU compatibility (avoiding SIGILL)

If you see SIGILL: illegal instruction when running tests, the CPU or VM does not support the SIMD instructions used by that code.

Check support on Linux

# List SIMD-related flags
grep -E 'avx' /proc/cpuinfo

# Or with lscpu
lscpu | grep -i avx

Rough mapping:

Tests / code	Required flag(s)	Typical CPUs
AVX (128-bit)	avx (baseline on amd64)	All amd64
AVX2 (256-bit)	avx2	Intel Haswell+, AMD Excavator+
AVX-512 (512-bit)	avx512f	Intel Skylake-X+, some Xeons; many AMD/consumer CPUs do not have it

What the tests do

• AVX tests (128-bit) call requireAVX(t) and are skipped if the CPU does not support AVX.
• AVX2 tests call requireAVX2(t) and are skipped if the CPU does not support AVX2 (no SIGILL).
• AVX-512 tests (when enabled) should call requireAVX512(t) and skip when AVX-512 is not available.

So on a machine without AVX2, AVX2 tests will show as skipped instead of crashing.

Run only AVX tests

If your environment does not support AVX2/AVX-512, you can still run the AVX (128-bit) tests:

GOEXPERIMENT=simd go test -run AVX ./...