diff --git a/.github/workflows/clang-tests.yml b/.github/workflows/clang-tests.yml
deleted file mode 100644
index 2569ce19518e3e3..000000000000000
--- a/.github/workflows/clang-tests.yml
+++ /dev/null
@@ -1,38 +0,0 @@
-name: Clang Tests
-
-permissions:
-  contents: read
-
-on:
-  workflow_dispatch:
-  push:
-    branches:
-      - 'release/**'
-    paths:
-      - 'clang/**'
-      - '.github/workflows/clang-tests.yml'
-      - '.github/workflows/llvm-project-tests.yml'
-      - '!llvm/**'
-  pull_request:
-    branches:
-      - 'release/**'
-    paths:
-      - 'clang/**'
-      - '.github/workflows/clang-tests.yml'
-      - '.github/workflows/llvm-project-tests.yml'
-      - '!llvm/**'
-
-concurrency:
-  # Skip intermediate builds: always.
-  # Cancel intermediate builds: only if it is a pull request build.
-  group: ${{ github.workflow }}-${{ github.ref }}
-  cancel-in-progress: ${{ startsWith(github.ref, 'refs/pull/') }}
-
-jobs:
-  check_clang:
-    if: github.repository_owner == 'llvm'
-    name: Test clang,lldb,libclc
-    uses: ./.github/workflows/llvm-project-tests.yml
-    with:
-      build_target: check-clang
-      projects: clang;lldb;libclc
diff --git a/.github/workflows/libclc-tests.yml b/.github/workflows/libclc-tests.yml
deleted file mode 100644
index 23192f776a985e1..000000000000000
--- a/.github/workflows/libclc-tests.yml
+++ /dev/null
@@ -1,39 +0,0 @@
-name: libclc Tests
-
-permissions:
-  contents: read
-
-on:
-  workflow_dispatch:
-  push:
-    branches:
-      - 'release/**'
-    paths:
-      - 'libclc/**'
-      - '.github/workflows/libclc-tests.yml'
-      - '.github/workflows/llvm-project-tests.yml'
-      - '!clang/**'
-      - '!llvm/**'
-  pull_request:
-    branches:
-      - 'release/**'
-    paths:
-      - 'libclc/**'
-      - '.github/workflows/libclc-tests.yml'
-      - '.github/workflows/llvm-project-tests.yml'
-      - '!clang/**'
-      - '!llvm/**'
-
-concurrency:
-  # Skip intermediate builds: always.
-  # Cancel intermediate builds: only if it is a pull request build.
-  group: ${{ github.workflow }}-${{ github.ref }}
-  cancel-in-progress: ${{ startsWith(github.ref, 'refs/pull/') }}
-
-jobs:
-  check_libclc:
-    if: github.repository_owner == 'llvm'
-    name: Test libclc
-    uses: ./.github/workflows/llvm-project-tests.yml
-    with:
-      projects: clang;libclc
diff --git a/.github/workflows/lld-tests.yml b/.github/workflows/lld-tests.yml
deleted file mode 100644
index 599c0975fa68586..000000000000000
--- a/.github/workflows/lld-tests.yml
+++ /dev/null
@@ -1,38 +0,0 @@
-name: LLD Tests
-
-permissions:
-  contents: read
-
-on:
-  workflow_dispatch:
-  push:
-    branches:
-      - 'release/**'
-    paths:
-      - 'lld/**'
-      - '.github/workflows/lld-tests.yml'
-      - '.github/workflows/llvm-project-tests.yml'
-      - '!llvm/**'
-  pull_request:
-    branches:
-      - 'release/**'
-    paths:
-      - 'lld/**'
-      - '.github/workflows/lld-tests.yml'
-      - '.github/workflows/llvm-project-tests.yml'
-      - '!llvm/**'
-
-concurrency:
-  # Skip intermediate builds: always.
-  # Cancel intermediate builds: only if it is a pull request build.
-  group: ${{ github.workflow }}-${{ github.ref }}
-  cancel-in-progress: ${{ startsWith(github.ref, 'refs/pull/') }}
-
-jobs:
-  check_lld:
-    if: github.repository_owner == 'llvm'
-    name: Test lld
-    uses: ./.github/workflows/llvm-project-tests.yml
-    with:
-      build_target: check-lld
-      projects: lld
diff --git a/.github/workflows/lldb-tests.yml b/.github/workflows/lldb-tests.yml
deleted file mode 100644
index 6bb9721956258f1..000000000000000
--- a/.github/workflows/lldb-tests.yml
+++ /dev/null
@@ -1,39 +0,0 @@
-name: lldb Tests
-
-permissions:
-  contents: read
-
-on:
-  workflow_dispatch:
-  push:
-    branches:
-      - 'release/**'
-    paths:
-      - 'lldb/**'
-      - '.github/workflows/lldb-tests.yml'
-      - '.github/workflows/llvm-project-tests.yml'
-      - '!clang/**'
-      - '!llvm/**'
-  pull_request:
-    branches:
-      - 'release/**'
-    paths:
-      - 'lldb/**'
-      - '.github/workflows/lldb-tests.yml'
-      - '.github/workflows/llvm-project-tests.yml'
-      - '!clang/**'
-      - '!llvm/**'
-
-concurrency:
-  # Skip intermediate builds: always.
-  # Cancel intermediate builds: only if it is a pull request build.
-  group: ${{ github.workflow }}-${{ github.ref }}
-  cancel-in-progress: ${{ startsWith(github.ref, 'refs/pull/') }}
-
-jobs:
-  build_lldb:
-    if: github.repository_owner == 'llvm'
-    name: Build lldb
-    uses: ./.github/workflows/llvm-project-tests.yml
-    with:
-      projects: clang;lldb
diff --git a/.github/workflows/llvm-tests.yml b/.github/workflows/llvm-tests.yml
index 4e570a7cb145500..9b3d49d4e99b93b 100644
--- a/.github/workflows/llvm-tests.yml
+++ b/.github/workflows/llvm-tests.yml
@@ -11,14 +11,12 @@ on:
     paths:
       - 'llvm/**'
       - '.github/workflows/llvm-tests.yml'
-      - '.github/workflows/llvm-project-tests.yml'
   pull_request:
     branches:
       - 'release/**'
     paths:
       - 'llvm/**'
       - '.github/workflows/llvm-tests.yml'
-      - '.github/workflows/llvm-project-tests.yml'
 
 concurrency:
   # Skip intermediate builds: always.
@@ -27,14 +25,6 @@ concurrency:
   cancel-in-progress: ${{ startsWith(github.ref, 'refs/pull/') }}
 
 jobs:
-  check-all:
-    if: github.repository_owner == 'llvm'
-    name: Build and Test
-    uses: ./.github/workflows/llvm-project-tests.yml
-    with:
-      build_target: check-all
-      projects: clang;lld;libclc;lldb
-
   abi-dump-setup:
     if: github.repository_owner == 'llvm'
     runs-on: ubuntu-latest
diff --git a/.github/workflows/premerge.yaml b/.github/workflows/premerge.yaml
index 54d6e1bf092cfb5..d7fa67188218614 100644
--- a/.github/workflows/premerge.yaml
+++ b/.github/workflows/premerge.yaml
@@ -10,6 +10,7 @@ on:
   push:
     branches:
       - 'main'
+      - 'release/**'
 
 jobs:
   premerge-checks-linux:
@@ -132,3 +133,72 @@ jobs:
           call C:\\BuildTools\\Common7\\Tools\\VsDevCmd.bat -arch=amd64 -host_arch=amd64
           bash .ci/monolithic-windows.sh "${{ steps.vars.outputs.windows-projects }}" "${{ steps.vars.outputs.windows-check-targets }}"
 
+  permerge-check-macos:
+    runs-on: macos-14
+    concurrency:
+      group: ${{ github.workflow }}-macos-${{ github.event.pull_request.number || github.sha }}
+      cancel-in-progress: true
+    if: >-
+      (startswith(github.ref_name, 'release/') ||
+       startswith(github.base_ref, 'refs/heads/release/'))
+    steps:
+      - name: Checkout LLVM
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 2
+      - name: Setup ccache
+        uses: hendrikmuhs/[email protected]
+        with:
+          max-size: "2000M"
+      - name: Install Ninja
+        uses: llvm/actions/install-ninja@main
+      - name: Build and Test
+        run: |
+          modified_files=$(git diff --name-only HEAD~1...HEAD)
+          modified_dirs=$(echo "$modified_files" | cut -d'/' -f1 | sort -u)
+
+          echo $modified_files
+          echo $modified_dirs
+
+          . ./.ci/compute-projects.sh
+
+          all_projects="clang clang-tools-extra lld lldb llvm mlir"
+          modified_projects="$(keep-modified-projects ${all_projects})"
+
+          # We have to disable the runtimes builds due to https://github.com/llvm/llvm-project/issues/90568
+          # and the lldb tests depend on libcxx, so we need to skip them.
+          mac_check_targets=$(check-targets ${modified_projects} | sort | uniq | tr '\n' ' ' | sed -e 's/check-lldb //g')
+          mac_projects=$(add-dependencies ${modified_projects} | sort | uniq | tr '\n' ' ')
+
+          mac_runtimes_to_test=$(compute-runtimes-to-test ${modified_projects})
+          mac_runtime_check_targets=$(check-targets ${mac_runtimes_to_test} | sort | uniq | tr '\n' ' ')
+          mac_runtimes=$(echo ${mac_runtimes_to_test} | tr ' ' '\n' | sort | uniq | tr '\n' ' ')
+
+          if [[ "${mac_projects}" == "" ]]; then
+            echo "No projects to build"
+            exit 0
+          fi
+
+          echo "Projects to test: ${modified_projects}"
+          echo "Runtimes to test: ${mac_runtimes_to_test}"
+          echo "Building projects: ${mac_projects}"
+          echo "Running project checks targets: ${mac_check_targets}"
+          echo "Building runtimes: ${mac_runtimes}"
+          echo "Running runtimes checks targets: ${mac_runtime_check_targets}"
+
+          # -DLLVM_DISABLE_ASSEMBLY_FILES=ON is for
+          # https://github.com/llvm/llvm-project/issues/81967
+          # Disable sharding in lit so that the LIT_XFAIL environment var works.
+          cmake -G Ninja \
+                -B build \
+                -S llvm \
+                -DLLVM_ENABLE_PROJECTS="$(echo ${mac_projects} | tr ' ' ';')" \
+                -DLLVM_DISABLE_ASSEMBLY_FILES=ON \
+                -DCMAKE_BUILD_TYPE=Release \
+                -DLLDB_INCLUDE_TESTS=OFF \
+                -DLLVM_ENABLE_ASSERTIONS=ON \
+                -DCMAKE_C_COMPILER_LAUNCHER=ccache \
+                -DCMAKE_CXX_COMPILER_LAUNCHER=ccache
+
+          # The libcxx tests fail, so we are skipping the runtime targets.
+          ninja -C build  $mac_check_targets