ci.yml

name: CI

on:
  push:
    branches: [main]
  pull_request:
    branches: [main]

env:
  GOEXPERIMENT: simd

jobs:
  # Compiling never executes vector instructions, so every tag builds
  # successfully regardless of the runner's actual CPU features. Running
  # actually executes them, so only tags whose instruction set is reliably
  # present on GitHub-hosted runners are also tested here (AVX-512 is not —
  # see the avx512 job below).
  build-and-test:
    name: build-and-test (${{ matrix.tags }})
    runs-on: ubuntu-latest
    strategy:
      fail-fast: false
      matrix:
        tags: [simd_avx256, simd_avx512, simd_none]
    steps:
      - name: Checkout
        uses: actions/checkout@v7

      - name: Set up Go
        uses: actions/setup-go@v7
        with:
          go-version-file: go.mod

      - name: Build
        run: go build -tags ${{ matrix.tags }} ./...

      - name: Test
        if: matrix.tags != 'simd_avx512'
        run: go test -tags ${{ matrix.tags }} ./... --cover

  # GitHub-hosted runners inconsistently expose AVX-512 to the guest VM
  # (many Azure SKUs mask it even when the host CPU supports it), so this
  # job is best-effort: it skips itself when the runner has no AVX-512, and
  # is allowed to fail rather than block CI when it does run.
  test-avx512:
    name: test-avx512
    runs-on: ubuntu-latest
    continue-on-error: true
    steps:
      - name: Checkout
        uses: actions/checkout@v7

      - name: Set up Go
        uses: actions/setup-go@v7
        with:
          go-version-file: go.mod

      - name: Check for AVX-512 support
        id: cpu
        run: |
          if grep -qm1 avx512 /proc/cpuinfo; then
            echo "has_avx512=true" >> "$GITHUB_OUTPUT"
          else
            echo "has_avx512=false" >> "$GITHUB_OUTPUT"
          fi

      - name: Test simd_avx512
        if: steps.cpu.outputs.has_avx512 == 'true'
        run: go test -tags simd_avx512 ./... --cover

      - name: Skip (no AVX-512 on this runner)
        if: steps.cpu.outputs.has_avx512 == 'false'
        run: echo "Runner has no AVX-512; skipping execution."