diff --git a/.ci/compute_projects.py b/.ci/compute_projects.py
index a4cfecf0cef9..4a72ee7b7cd1 100644
--- a/.ci/compute_projects.py
+++ b/.ci/compute_projects.py
@@ -40,56 +40,29 @@
 # tested.
 DEPENDENTS_TO_TEST = {
     "llvm": {
-        "bolt",
         "clang",
-        "clang-tools-extra",
-        "lld",
-        "lldb",
         "mlir",
-        "polly",
-        "flang",
     },
-    "lld": {"bolt", "cross-project-tests"},
-    "clang": {"clang-tools-extra", "cross-project-tests", "lldb"},
-    "mlir": {"flang"},
+    "lld": {},
+    "clang": {},
+    "mlir": {},
     # Test everything if ci scripts are changed.
     ".ci": {
         "llvm",
         "clang",
         "CIR",
-        "lld",
-        "lldb",
-        "bolt",
-        "clang-tools-extra",
-        "mlir",
-        "polly",
-        "flang",
-        "libclc",
-        "openmp",
     },
 }
 
 # This mapping describes runtimes that should be enabled for a specific project,
 # but not necessarily run for testing. The only case of this currently is lldb
 # which needs some runtimes enabled for tests.
-DEPENDENT_RUNTIMES_TO_BUILD = {"lldb": {"libcxx", "libcxxabi", "libunwind"}}
+DEPENDENT_RUNTIMES_TO_BUILD = {}
 
 # This mapping describes runtimes that should be tested when the key project is
 # touched.
-DEPENDENT_RUNTIMES_TO_TEST = {
-    "clang": {"compiler-rt"},
-    "clang-tools-extra": {"libc"},
-    "libc": {"libc"},
-    "compiler-rt": {"compiler-rt"},
-    "flang": {"flang-rt"},
-    "flang-rt": {"flang-rt"},
-    ".ci": {"compiler-rt", "libc", "flang-rt"},
-}
-DEPENDENT_RUNTIMES_TO_TEST_NEEDS_RECONFIG = {
-    "llvm": {"libcxx", "libcxxabi", "libunwind"},
-    "clang": {"libcxx", "libcxxabi", "libunwind"},
-    ".ci": {"libcxx", "libcxxabi", "libunwind"},
-}
+DEPENDENT_RUNTIMES_TO_TEST = {}
+DEPENDENT_RUNTIMES_TO_TEST_NEEDS_RECONFIG = {}
 
 EXCLUDE_LINUX = {
     "cross-project-tests",  # TODO(issues/132796): Tests are failing.
@@ -138,7 +111,7 @@
     "libunwind": "check-unwind",
     "lldb": "check-lldb",
     "llvm": "check-llvm",
-    "clang": "check-clang",
+    "clang": "check-clang-cir",
     "CIR": "check-clang-cir",
     "bolt": "check-bolt",
     "lld": "check-lld",
diff --git a/.ci/monolithic-linux.sh b/.ci/monolithic-linux.sh
index 50992379b71c..55fed22b1f42 100755
--- a/.ci/monolithic-linux.sh
+++ b/.ci/monolithic-linux.sh
@@ -40,12 +40,12 @@ export LLVM_SYMBOLIZER_PATH=`which llvm-symbolizer`
 # Set up all runtimes either way. libcxx is a dependency of LLDB.
 # It will not be built unless it is used.
 cmake -S "${MONOREPO_ROOT}"/llvm -B "${BUILD_DIR}" \
-      -D LLVM_ENABLE_PROJECTS="${projects}" \
-      -D LLVM_ENABLE_RUNTIMES="${runtimes}" \
+      -D LLVM_ENABLE_PROJECTS="clang;mlir" \
+      -D LLVM_TARGETS_TO_BUILD='X86;AArch64' \
       -G Ninja \
       -D CMAKE_PREFIX_PATH="${HOME}/.local" \
       -D CMAKE_BUILD_TYPE=Release \
-      -D CLANG_ENABLE_CIR=${enable_cir} \
+      -D CLANG_ENABLE_CIR=ON \
       -D LLVM_ENABLE_ASSERTIONS=ON \
       -D LLVM_BUILD_EXAMPLES=ON \
       -D COMPILER_RT_BUILD_LIBFUZZER=OFF \
@@ -59,8 +59,7 @@ cmake -S "${MONOREPO_ROOT}"/llvm -B "${BUILD_DIR}" \
       -D LLDB_ENABLE_PYTHON=ON \
       -D LLDB_ENFORCE_STRICT_TEST_REQUIREMENTS=ON \
       -D CMAKE_INSTALL_PREFIX="${INSTALL_DIR}" \
-      -D CMAKE_EXE_LINKER_FLAGS="-no-pie" \
-      -D LLVM_ENABLE_WERROR=ON
+      -D CMAKE_EXE_LINKER_FLAGS="-no-pie"
 
 start-group "ninja"
 
diff --git a/.ci/monolithic-windows.sh b/.ci/monolithic-windows.sh
index ff112fa78f60..33210970b1f2 100755
--- a/.ci/monolithic-windows.sh
+++ b/.ci/monolithic-windows.sh
@@ -36,10 +36,11 @@ export LD=link
 # https://discourse.llvm.org/t/rfc-future-of-windows-pre-commit-ci/76840/40
 # for further information.
 cmake -S "${MONOREPO_ROOT}"/llvm -B "${BUILD_DIR}" \
-      -D LLVM_ENABLE_PROJECTS="${projects}" \
+      -D LLVM_ENABLE_PROJECTS="clang;mlir" \
       -G Ninja \
       -D CMAKE_BUILD_TYPE=Release \
-      -D CLANG_ENABLE_CIR="${enable_cir}" \
+      -D LLVM_TARGETS_TO_BUILD="X86;AArch64" \
+      -D CLANG_ENABLE_CIR=ON \
       -D LLVM_ENABLE_ASSERTIONS=ON \
       -D LLVM_BUILD_EXAMPLES=ON \
       -D COMPILER_RT_BUILD_LIBFUZZER=OFF \
diff --git a/.github/workflows/premerge.yaml b/.github/workflows/premerge.yaml
index 8503b2d62c5e..790c70cc568f 100644
--- a/.github/workflows/premerge.yaml
+++ b/.github/workflows/premerge.yaml
@@ -32,7 +32,6 @@ jobs:
       fail-fast: false
       matrix:
         runs-on:
-          - depot-ubuntu-24.04-arm-16
           - llvm-premerge-linux-runners
     runs-on: ${{ matrix.runs-on }}
     container:
@@ -209,6 +208,7 @@ jobs:
           cmake -G Ninja \
                 -B build \
                 -S llvm \
+                -DLLVM_TARGETS_TO_BUILD=AArch64;X86 \
                 -DLLVM_ENABLE_PROJECTS="${projects_to_build}" \
                 -DLLVM_DISABLE_ASSEMBLY_FILES=ON \
                 -DCMAKE_BUILD_TYPE=Release \