diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index e657ad930ef05..5e59b65edde16 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -572,6 +572,16 @@ jobs:
         include:
           - sys: "clang64"
             os: "windows-latest"
+            auto-var-init: "uninitialized"
+          - sys: "clang64"
+            os: "windows-latest"
+            asan: true
+          - sys: "clang64"
+            os: "windows-latest"
+            auto-var-init: "zero"
+          - sys: "clang64"
+            os: "windows-latest"
+            auto-var-init: "pattern"
           - sys: "mingw64"
             os: "windows-latest"
           - sys: "ucrt64"
@@ -627,6 +637,8 @@ jobs:
           ./ci/build-msys2.sh meson
         env:
           SYS: ${{ matrix.sys }}
+          ASAN: ${{ matrix.asan }}
+          AUTO_VAR_INIT: ${{ matrix.auto-var-init }}
 
       - name: Print meson log
         if: ${{ failure() && steps.build.outcome == 'failure' }}
diff --git a/ci/build-msys2.sh b/ci/build-msys2.sh
index 80bad4cbee1d6..9e2f88a377bed 100755
--- a/ci/build-msys2.sh
+++ b/ci/build-msys2.sh
@@ -8,21 +8,24 @@ args=(
   -D{egl-angle-lib,egl-angle-win32,pdf-build,rubberband,win32-smtc}=enabled
 )
 
-if [[ "$SYS" == "clang64" ]]; then
+if [[ -n "$ASAN" ]]; then
     args+=(
       -Db_sanitize=address,undefined
     )
 fi
 
+if [[ -n "$AUTO_VAR_INIT" ]]; then
+    args+=(
+        -Dc_args="-ftrivial-auto-var-init=$AUTO_VAR_INIT"
+        -Dcpp_args="-ftrivial-auto-var-init=$AUTO_VAR_INIT"
+    )
+fi
+
 echo "::group::Building subrandr"
 build_subrandr "/$SYS"
 echo "::endgroup::"
 args+=(-Dsubrandr=enabled)
 
-[[ "$SYS" == "clangarm64" ]] && args+=(
-  -Dpdf-build=disabled
-)
-
 meson setup build $common_args "${args[@]}"
 meson compile -C build
 ./build/mpv.com -v --no-config