[llvm] [Github][RFC] Add workflow to diff codegen on llvm-test-suite (PR #190010)

[Luke Lau via llvm-commits]

================
@@ -0,0 +1,136 @@
+# When /test-suite is commented on a PR, checks out the PR, builds clang and
+# then the test-suite in several configurations. It then checks out the base of
+# the PR, builds clang and the test-suite again, and then uploads the diff of
+# the codegen.
+
+name: Diff test-suite codegen
+
+on:
+  issue_comment:
+    types:
+      - created
+
+jobs:
+  test-suite:
+    name: Build and diff
+    runs-on: ubuntu-24.04
+    permissions:
+      pull-requests: write
+    if: >-
+      !startswith(github.event.comment.body, '<!--IGNORE-->') &&
+      github.event.issue.pull_request && contains(github.event.comment.body, '/test-suite')
+    steps:
+      - name: Get pull request
+        id: get-pr
+        uses: actions/github-script at ed597411d8f924073f98dfc5c65a23a2325f34cd # v8.0.0
+        with:
+          script: |
+            const { data: pr } = await github.rest.pulls.get({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              pull_number: context.payload.issue.number
+            })
+            if (!pr.mergeable)
+              await github.rest.issues.createComment({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                body: "Can't diff PR, PR isn't mergeable"
+              })
+            return pr
+      - name: Check pull request is mergeable
+        if: ${{ !fromJSON(steps.get-pr.outputs.result).mergeable }}
+        run: exit 1
+      - name: Thumbs up comment
+        uses: actions/github-script at ed597411d8f924073f98dfc5c65a23a2325f34cd # v8.0.0
+        with:
+          script: |
+            github.rest.reactions.createForIssueComment({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              comment_id: context.payload.comment.id,
+              content: '+1'
+            })
+      - name: Checkout pull request
+        uses: actions/checkout at 8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          ref: ${{ fromJSON(steps.get-pr.outputs.result).merge_commit_sha }}
+          repository: ${{ fromJSON(steps.get-pr.outputs.result).head.repo.full_name }}
+          fetch-depth: 2
+          path: llvm-project
+      # Check out the test-suite scripts and CMake files from the default branch
+      # on the upstream repository. Use these instead of the scripts in the pull
+      # request's branch since it's untrusted.
+      - name: Checkout scripts and CMake files
+        uses: actions/checkout at 8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          path: scripts
+          sparse-checkout: .github/workflows/test-suite
----------------
lukel97 wrote:

This workflow definition is taken from the default branch too, I've set my own forks default branch to this PR for testing. Do you still want me to precommit it?

https://github.com/llvm/llvm-project/pull/190010