[llvm] [Github] Force premerge to run on US West cluster (PR #161535)

[Aiden Grossman via llvm-commits]

https://github.com/boomanaiden154 updated https://github.com/llvm/llvm-project/pull/161535

>From f05413e02ab4a1cc4e7a721dd1efd532b247c25f Mon Sep 17 00:00:00 2001
From: Aiden Grossman <aidengrossman at google.com>
Date: Wed, 1 Oct 2025 15:10:51 +0000
Subject: [PATCH 1/6] [Github] Force premerge to run on US West cluster

To debug why the US West cluster is not getting any jobs assigned.

DO NOT MERGE.
---
 .github/workflows/premerge.yaml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/premerge.yaml b/.github/workflows/premerge.yaml
index a9c107e4a5f08..542466a43796b 100644
--- a/.github/workflows/premerge.yaml
+++ b/.github/workflows/premerge.yaml
@@ -28,7 +28,8 @@ jobs:
     if: >-
         github.repository_owner == 'llvm' &&
         (github.event_name != 'pull_request' || github.event.action != 'closed')
-    runs-on: llvm-premerge-linux-runners
+    runs-on:
+      group: llvm-premerge-cluster-us-west
     steps:
       - name: Checkout LLVM
         uses: actions/checkout at 08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0

>From f40ac7d0e397a29cf172a14b440db2e087d0b486 Mon Sep 17 00:00:00 2001
From: Aiden Grossman <aidengrossman at google.com>
Date: Wed, 1 Oct 2025 15:13:36 +0000
Subject: [PATCH 2/6] test

---
 .github/workflows/premerge.yaml | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/.github/workflows/premerge.yaml b/.github/workflows/premerge.yaml
index 542466a43796b..a9c107e4a5f08 100644
--- a/.github/workflows/premerge.yaml
+++ b/.github/workflows/premerge.yaml
@@ -28,8 +28,7 @@ jobs:
     if: >-
         github.repository_owner == 'llvm' &&
         (github.event_name != 'pull_request' || github.event.action != 'closed')
-    runs-on:
-      group: llvm-premerge-cluster-us-west
+    runs-on: llvm-premerge-linux-runners
     steps:
       - name: Checkout LLVM
         uses: actions/checkout at 08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0

>From 1a602ba2c53a253e6ae8fcc30af97a6e23c2d583 Mon Sep 17 00:00:00 2001
From: Aiden Grossman <aidengrossman at google.com>
Date: Wed, 1 Oct 2025 15:14:12 +0000
Subject: [PATCH 3/6] change back

---
 .github/workflows/premerge.yaml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/premerge.yaml b/.github/workflows/premerge.yaml
index a9c107e4a5f08..542466a43796b 100644
--- a/.github/workflows/premerge.yaml
+++ b/.github/workflows/premerge.yaml
@@ -28,7 +28,8 @@ jobs:
     if: >-
         github.repository_owner == 'llvm' &&
         (github.event_name != 'pull_request' || github.event.action != 'closed')
-    runs-on: llvm-premerge-linux-runners
+    runs-on:
+      group: llvm-premerge-cluster-us-west
     steps:
       - name: Checkout LLVM
         uses: actions/checkout at 08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0

>From dddb5f0b23af2bcc7b3d5abe3a06cbb0e164b31c Mon Sep 17 00:00:00 2001
From: Aiden Grossman <aidengrossman at google.com>
Date: Wed, 1 Oct 2025 15:16:34 +0000
Subject: [PATCH 4/6] force label

---
 .github/workflows/premerge.yaml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.github/workflows/premerge.yaml b/.github/workflows/premerge.yaml
index 542466a43796b..4adedf1ddca86 100644
--- a/.github/workflows/premerge.yaml
+++ b/.github/workflows/premerge.yaml
@@ -30,6 +30,7 @@ jobs:
         (github.event_name != 'pull_request' || github.event.action != 'closed')
     runs-on:
       group: llvm-premerge-cluster-us-west
+      label: llvm-premerge-linux-runners
     steps:
       - name: Checkout LLVM
         uses: actions/checkout at 08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0

>From 5b4061317f6b9ebc8e1181ffa437cbe0089afd22 Mon Sep 17 00:00:00 2001
From: Aiden Grossman <aidengrossman at google.com>
Date: Wed, 1 Oct 2025 15:18:13 +0000
Subject: [PATCH 5/6] fix syntax

---
 .github/workflows/premerge.yaml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/premerge.yaml b/.github/workflows/premerge.yaml
index 4adedf1ddca86..d3b2a8da40c99 100644
--- a/.github/workflows/premerge.yaml
+++ b/.github/workflows/premerge.yaml
@@ -30,7 +30,7 @@ jobs:
         (github.event_name != 'pull_request' || github.event.action != 'closed')
     runs-on:
       group: llvm-premerge-cluster-us-west
-      label: llvm-premerge-linux-runners
+      labels: llvm-premerge-linux-runners
     steps:
       - name: Checkout LLVM
         uses: actions/checkout at 08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0

>From 5db37399aa0c752ab783c1ed4fce898bdb3ff069 Mon Sep 17 00:00:00 2001
From: Aiden Grossman <aidengrossman at google.com>
Date: Wed, 1 Oct 2025 15:39:00 +0000
Subject: [PATCH 6/6] try modulo

---
 .github/workflows/premerge.yaml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/premerge.yaml b/.github/workflows/premerge.yaml
index d3b2a8da40c99..e2cc400c9bfcf 100644
--- a/.github/workflows/premerge.yaml
+++ b/.github/workflows/premerge.yaml
@@ -29,7 +29,7 @@ jobs:
         github.repository_owner == 'llvm' &&
         (github.event_name != 'pull_request' || github.event.action != 'closed')
     runs-on:
-      group: llvm-premerge-cluster-us-west
+      group: ${{ github.run_id % 2 == 0 && 'llvm-premerge-cluster-us-west' || 'llvm-premerge-cluster-us-central' }}
       labels: llvm-premerge-linux-runners
     steps:
       - name: Checkout LLVM