[Tarantool-patches] [PATCH luajit 1/4][v2] ci: add a workflow for testing with AVX512

[Sergey Bronnikov via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

From: Sergey Bronnikov <sergeyb@tarantool.org>

This commit adds a workflow for building and testing with enabled
AVX512.

Needed for tarantool/tarantool#9595
Related to tarantool/tarantool#6787
---
 .github/actions/setup-linux/action.yml     | 12 +++++
 .github/workflows/avx512-build-testing.yml | 54 ++++++++++++++++++++++
 test/LuaJIT-tests/lib/ffi/bit64.lua        |  2 +-
 3 files changed, 67 insertions(+), 1 deletion(-)
 create mode 100644 .github/workflows/avx512-build-testing.yml

diff --git a/.github/actions/setup-linux/action.yml b/.github/actions/setup-linux/action.yml
index f0171b83..19bdcfa2 100644
--- a/.github/actions/setup-linux/action.yml
+++ b/.github/actions/setup-linux/action.yml
@@ -17,3 +17,15 @@ runs:
         apt -y update
         apt -y install cmake gcc make ninja-build perl
       shell: bash
+    - name: Detect a presence of AVX512
+      id: avx512_script
+      run: |
+        # Set avx512_support environment variable to 'true' when AVX512
+        # is supported and 'false' otherwise.
+        #
+        # Normally `grep` has the exit status is 0 if a line is
+        # selected, 1 if no lines were selected, and 2 if an error
+        # occurred.
+        avx512_support=$(grep avx /proc/cpuinfo 2>&1 > /dev/null;  [[ $? == 0 ]] && echo 0 || echo 1)
+        echo "avx512_support=$avx512_support" >> $GITHUB_OUTPUT
+      shell: bash
diff --git a/.github/workflows/avx512-build-testing.yml b/.github/workflows/avx512-build-testing.yml
new file mode 100644
index 00000000..d70fa661
--- /dev/null
+++ b/.github/workflows/avx512-build-testing.yml
@@ -0,0 +1,54 @@
+name: "AVX512 build testing"
+
+on:
+  push:
+    branches-ignore:
+      - '**-notest'
+      - 'upstream-**'
+    tags-ignore:
+      - '**'
+
+concurrency:
+  # An update of a developer branch cancels the previously
+  # scheduled workflow run for this branch. However, the default
+  # branch, and long-term branch (tarantool/release/2.11,
+  # tarantool/release/2.10, etc) workflow runs are never canceled.
+  #
+  # We use a trick here: define the concurrency group as 'workflow
+  # run ID' + # 'workflow run attempt' because it is a unique
+  # combination for any run. So it effectively discards grouping.
+  #
+  # XXX: we cannot use `github.sha` as a unique identifier because
+  # pushing a tag may cancel a run that works on a branch push
+  # event.
+  group: ${{ startsWith(github.ref, 'refs/heads/tarantool/')
+    && format('{0}-{1}', github.run_id, github.run_attempt)
+    || format('{0}-{1}', github.workflow, github.ref) }}
+  cancel-in-progress: true
+
+jobs:
+  test-avx512:
+    strategy:
+      fail-fast: false
+    runs-on: [self-hosted, regular, x86_64, Linux]
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          submodules: recursive
+      - name: setup Linux
+        uses: ./.github/actions/setup-linux
+      - name: configure
+        if: needs.avx512_script.outputs.avx512_support == 0
+        run: >
+          cmake -S . -B ${{ env.BUILDDIR }}
+          -G Ninja
+          -DCMAKE_BUILD_TYPE=RelWithDebInfo
+          -DCMAKE_C_FLAGS=-march=skylake-avx512
+          -DCMAKE_C_COMPILER=gcc
+      - name: build
+        if: needs.avx512_script.outputs.avx512_support == 0
+        run: cmake --build ${{ env.BUILDDIR }} --parallel
+      - name: run regression tests
+        if: needs.avx512_script.outputs.avx512_support == 0
+        run: cmake --build ${{ env.BUILDDIR }} --parallel --target LuaJIT-test
diff --git a/test/LuaJIT-tests/lib/ffi/bit64.lua b/test/LuaJIT-tests/lib/ffi/bit64.lua
index d1b47bef..cf3a96eb 100644
--- a/test/LuaJIT-tests/lib/ffi/bit64.lua
+++ b/test/LuaJIT-tests/lib/ffi/bit64.lua
@@ -41,7 +41,7 @@ do --- tobit/band assorted C types
   end
 end
 
-do --- tobit/band negative unsigned enum
+do --- tobit/band negative unsigned enum -avx512
   local x = ffi.new("uenum_t", -10)
   local y = tobit(x)
   local z = band(x)
-- 
2.34.1