diff --git a/.github/workflows/libc-fullbuild-tests.yml b/.github/workflows/libc-fullbuild-tests.yml
index 24d75f58d45e0..9b2d8dd579702 100644
--- a/.github/workflows/libc-fullbuild-tests.yml
+++ b/.github/workflows/libc-fullbuild-tests.yml
@@ -15,9 +15,25 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        build_type: [Debug, Release, MinSizeRel]
+        # Build basic linux configuration with Debug/Release/MinSizeRel and all
+        # other configurations in Debug only.
         include:
           - os: ubuntu-24.04
+            build_type: Debug
+            ccache-variant: sccache
+            c_compiler: clang-21
+            cpp_compiler: clang++-21
+            target: x86_64-unknown-linux-llvm
+            include_scudo: ON
+          - os: ubuntu-24.04
+            build_type: Release
+            ccache-variant: sccache
+            c_compiler: clang-21
+            cpp_compiler: clang++-21
+            target: x86_64-unknown-linux-llvm
+            include_scudo: ON
+          - os: ubuntu-24.04
+            build_type: MinSizeRel
             ccache-variant: sccache
             c_compiler: clang-21
             cpp_compiler: clang++-21
@@ -25,12 +41,14 @@ jobs:
             include_scudo: ON
           # TODO: remove ccache logic when https://github.com/hendrikmuhs/ccache-action/issues/279 is resolved.
           - os: ubuntu-24.04-arm
+            build_type: Debug
             ccache-variant: ccache
             c_compiler: clang-21
             cpp_compiler: clang++-21
             target: aarch64-unknown-linux-llvm
             include_scudo: ON
           - os: ubuntu-24.04
+            build_type: Debug
             ccache-variant: ccache
             c_compiler: clang-21
             cpp_compiler: clang++-21
@@ -97,7 +115,7 @@ jobs:
         -DCMAKE_C_COMPILER_LAUNCHER=${{ matrix.ccache-variant }} \
         -DCMAKE_CXX_COMPILER_LAUNCHER=${{ matrix.ccache-variant }} \
         -DCMAKE_INSTALL_PREFIX=${{ steps.strings.outputs.build-install-dir }} \
-        -DLLVM_RUNTIMES_TARGET=${{ matrix.target }} \
+        -DLLVM_RUNTIME_TARGETS=${{ matrix.target }} \
         -DLLVM_ENABLE_RUNTIMES="$RUNTIMES" \
         -DLLVM_LIBC_FULL_BUILD=ON \
         -G Ninja \
diff --git a/.github/workflows/libc-overlay-tests.yml b/.github/workflows/libc-overlay-tests.yml
index da82d8d9fe8ab..f001daae030a3 100644
--- a/.github/workflows/libc-overlay-tests.yml
+++ b/.github/workflows/libc-overlay-tests.yml
@@ -16,7 +16,7 @@ jobs:
       # Set fail-fast to false to ensure that feedback is delivered for all matrix combinations.
       fail-fast: false
       matrix:
-        build_type: [Debug, Release, MinSizeRel]
+        os: [ubuntu-24.04, ubuntu-24.04-arm, windows-2022, windows-2025, macos-14]
         include:
           # TODO: add linux gcc when it is fixed
           - os: ubuntu-24.04
@@ -96,7 +96,7 @@ jobs:
         cmake -B ${{ steps.strings.outputs.build-output-dir }}
         -DCMAKE_CXX_COMPILER=${{ matrix.compiler.cpp_compiler }}
         -DCMAKE_C_COMPILER=${{ matrix.compiler.c_compiler }}
-        -DCMAKE_BUILD_TYPE=${{ matrix.build_type }}
+        -DCMAKE_BUILD_TYPE=Debug
         -DCMAKE_C_COMPILER_LAUNCHER=${{ matrix.ccache-variant }}
         -DCMAKE_CXX_COMPILER_LAUNCHER=${{ matrix.ccache-variant }}
         -DCMAKE_POLICY_DEFAULT_CMP0141=NEW
@@ -110,7 +110,6 @@ jobs:
         cmake 
         --build ${{ steps.strings.outputs.build-output-dir }} 
         --parallel 
-        --config MinSizeRel 
         --target libc
 
     - name: Test