diff --git a/libcxx/utils/ci/buildkite-pipeline.yml b/libcxx/utils/ci/buildkite-pipeline.yml
--- a/libcxx/utils/ci/buildkite-pipeline.yml
+++ b/libcxx/utils/ci/buildkite-pipeline.yml
@@ -28,306 +28,13 @@
     soft_fail:
         - exit_status: 1
 
-  - label: "C++03"
-    command: "libcxx/utils/ci/run-buildbot generic-cxx03"
+  - label: "Runtimes build"
+    command: "libcxx/utils/ci/run-buildbot runtimes-build"
     artifact_paths:
       - "**/test-results.xml"
-      - "**/*.abilist"
     agents:
       queue: "libcxx-builders"
     retry:
       automatic:
         - exit_status: -1  # Agent was lost
           limit: 2
-
-  - label: "C++11"
-    command: "libcxx/utils/ci/run-buildbot generic-cxx11"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    agents:
-      queue: "libcxx-builders"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-
-  - label: "C++14"
-    command: "libcxx/utils/ci/run-buildbot generic-cxx14"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    agents:
-      queue: "libcxx-builders"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-
-  - label: "C++17"
-    command: "libcxx/utils/ci/run-buildbot generic-cxx17"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    agents:
-      queue: "libcxx-builders"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-
-  - label: "C++20"
-    command: "libcxx/utils/ci/run-buildbot generic-cxx20"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    agents:
-      queue: "libcxx-builders"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-
-  - label: "C++2b"
-    command: "libcxx/utils/ci/run-buildbot generic-cxx2b"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    agents:
-      queue: "libcxx-builders"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-
-  - label: "-fno-exceptions"
-    command: "libcxx/utils/ci/run-buildbot generic-noexceptions"
-    artifact_paths:
-      - "**/test-results.xml"
-    agents:
-      queue: "libcxx-builders"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-
-  - label: "GCC/C++20"
-    command: "libcxx/utils/ci/run-buildbot generic-gcc"
-    artifact_paths:
-      - "**/test-results.xml"
-    agents:
-      queue: "libcxx-builders"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-
-  - label: "ASAN"
-    command: "libcxx/utils/ci/run-buildbot generic-asan"
-    artifact_paths:
-      - "**/test-results.xml"
-    agents:
-      queue: "libcxx-builders"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-
-  - label: "TSAN"
-    command: "libcxx/utils/ci/run-buildbot generic-tsan"
-    artifact_paths:
-      - "**/test-results.xml"
-    agents:
-      queue: "libcxx-builders"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-
-  - label: "UBSAN"
-    command: "libcxx/utils/ci/run-buildbot generic-ubsan"
-    artifact_paths:
-      - "**/test-results.xml"
-    agents:
-      queue: "libcxx-builders"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-
-  - label: "With LLVM's libunwind"
-    command: "libcxx/utils/ci/run-buildbot generic-with_llvm_unwinder"
-    artifact_paths:
-      - "**/test-results.xml"
-    agents:
-      queue: "libcxx-builders"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-
-  - label: "Single-threaded"
-    command: "libcxx/utils/ci/run-buildbot generic-singlethreaded"
-    artifact_paths:
-      - "**/test-results.xml"
-    agents:
-      queue: "libcxx-builders"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-
-  - label: "No debug mode"
-    command: "libcxx/utils/ci/run-buildbot generic-nodebug"
-    artifact_paths:
-      - "**/test-results.xml"
-    agents:
-      queue: "libcxx-builders"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-
-  - label: "No Filesystem"
-    command: "libcxx/utils/ci/run-buildbot generic-no-filesystem"
-    artifact_paths:
-      - "**/test-results.xml"
-    agents:
-      queue: "libcxx-builders"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-
-  - label: "No random device"
-    command: "libcxx/utils/ci/run-buildbot generic-no-random_device"
-    artifact_paths:
-      - "**/test-results.xml"
-    agents:
-      queue: "libcxx-builders"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-
-  - label: "No locale"
-    command: "libcxx/utils/ci/run-buildbot generic-no-localization"
-    artifact_paths:
-      - "**/test-results.xml"
-    agents:
-      queue: "libcxx-builders"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-
-  - label: "MacOS C++20"
-    command: "libcxx/utils/ci/run-buildbot generic-cxx20"
-    artifact_paths:
-      - "**/test-results.xml"
-      - "**/*.abilist"
-    agents:
-      queue: "libcxx-builders-macos"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-
-  - label: "Benchmarks"
-    command: "libcxx/utils/ci/run-buildbot benchmarks"
-    artifact_paths:
-      - "**/test-results.xml"
-    agents:
-      queue: "libcxx-builders"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-
-  - label: "Documentation"
-    command: "libcxx/utils/ci/run-buildbot documentation"
-    artifact_paths:
-      - "**/test-results.xml"
-    agents:
-      queue: "libcxx-builders"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-
-  - label: "Legacy standalone build"
-    command: "libcxx/utils/ci/run-buildbot legacy-standalone"
-    artifact_paths:
-      - "**/test-results.xml"
-    agents:
-      queue: "libcxx-builders"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-
-  - label: "Unified standalone build"
-    command: "libcxx/utils/ci/run-buildbot unified-standalone"
-    artifact_paths:
-      - "**/test-results.xml"
-    agents:
-      queue: "libcxx-builders"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-
-  # All jobs defined before this `wait` will run whenever a CI job is started.
-  # Jobs defined after the `wait` will run only if all the jobs above succeeded.
-  # We use this to reduce the load on testers that have more constrained resources
-  # and avoid running builds that we know fail anyway.
-  - wait
-
-  # Build with the configuration we use to generate libc++.dylib on Apple platforms
-  - label: "Apple system"
-    command: "libcxx/utils/ci/run-buildbot x86_64-apple-system"
-    artifact_paths:
-      - "**/test-results.xml"
-    agents:
-      queue: "libcxx-builders-macos"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-
-  - label: "Apple system -fno-exceptions"
-    command: "libcxx/utils/ci/run-buildbot x86_64-apple-system-noexceptions"
-    artifact_paths:
-      - "**/test-results.xml"
-    agents:
-      queue: "libcxx-builders-macos"
-    retry:
-      automatic:
-        - exit_status: -1  # Agent was lost
-          limit: 2
-
-  # TODO: Re-enable those as soon as Green Dragon is back online. Currently,
-  #       all the jobs are failing when they try to pull the older dylibs from
-  #       Green Dragon, which is down.
-  # # Test back-deployment to older Apple platforms
-  # - label: "Apple back-deployment macosx10.9"
-  #   command: "libcxx/utils/ci/run-buildbot x86_64-apple-system-backdeployment-10.9"
-  #   artifact_paths:
-  #     - "**/test-results.xml"
-  #   agents:
-  #     queue: "libcxx-builders-macos10.15" # TODO: For now, we're running the back-deployment tests for 10.9 on 10.15, because we don't have proper 10.9 machines
-  #   retry:
-  #     automatic:
-  #       - exit_status: -1  # Agent was lost
-  #         limit: 2
-
-  # - label: "Apple back-deployment macosx10.15"
-  #   command: "libcxx/utils/ci/run-buildbot x86_64-apple-system-backdeployment-10.15"
-  #   artifact_paths:
-  #     - "**/test-results.xml"
-  #   agents:
-  #     queue: "libcxx-builders-macos10.15"
-  #   retry:
-  #     automatic:
-  #       - exit_status: -1  # Agent was lost
-  #         limit: 2
diff --git a/libcxx/utils/ci/run-buildbot b/libcxx/utils/ci/run-buildbot
--- a/libcxx/utils/ci/run-buildbot
+++ b/libcxx/utils/ci/run-buildbot
@@ -345,6 +345,24 @@
 
     check-cxx-cxxabi
 ;;
+runtimes-build)
+    export CC=clang
+    export CXX=clang++
+
+    clean
+
+    echo "--- Generating CMake"
+    cmake -S "${MONOREPO_ROOT}/llvm" \
+          -B "${BUILD_DIR}" \
+          -GNinja \
+          -DCMAKE_BUILD_TYPE=RelWithDebInfo \
+          -DCMAKE_INSTALL_PREFIX="${INSTALL_DIR}" \
+          -DLLVM_ENABLE_PROJECTS="clang" \
+          -DLLVM_ENABLE_RUNTIMES="libcxx;libcxxabi" \
+          -DLLVM_RUNTIME_TARGETS="x86_64-unknown-linux"
+
+    check-cxx-cxxabi
+;;
 legacy-standalone)
     export CC=clang
     export CXX=clang++