diff --git a/.github/scripts/windows/build_task.bat b/.github/scripts/windows/build_task.bat
index b654794518496..9bc3f53463c37 100644
--- a/.github/scripts/windows/build_task.bat
+++ b/.github/scripts/windows/build_task.bat
@@ -26,12 +26,17 @@ if %errorlevel% neq 0 exit /b 3
 if "%THREAD_SAFE%" equ "0" set ADD_CONF=%ADD_CONF% --disable-zts
 if "%INTRINSICS%" neq "" set ADD_CONF=%ADD_CONF% --enable-native-intrinsics=%INTRINSICS%
 if "%ASAN%" equ "1" set ADD_CONF=%ADD_CONF% --enable-sanitizer --enable-debug-pack
+if "%CLANG_TOOLSET%" equ "1" set ADD_CONF=%ADD_CONF% --with-toolset=clang
 
 rem C4018: comparison: signed/unsigned mismatch
 rem C4146: unary minus operator applied to unsigned type
 rem C4244: type conversion, possible loss of data
 rem C4267: 'size_t' type conversion, possible loss of data
-set CFLAGS=/W3 /WX /wd4018 /wd4146 /wd4244 /wd4267
+if "%CLANG_TOOLSET%" equ "1" (
+	set CFLAGS=/W3 /wd4018 /wd4146 /wd4244 /wd4267
+) else (
+	set CFLAGS=/W3 /WX /wd4018 /wd4146 /wd4244 /wd4267
+)
 
 cmd /c configure.bat ^
 	--enable-snapshot-build ^
diff --git a/.github/workflows/test-suite.yml b/.github/workflows/test-suite.yml
index 9eeff1455f8f9..039ab8d5acdbb 100644
--- a/.github/workflows/test-suite.yml
+++ b/.github/workflows/test-suite.yml
@@ -962,6 +962,35 @@ jobs:
         run: .github/scripts/windows/build.bat
       - name: Test
         run: .github/scripts/windows/test.bat
+  WINDOWS_CLANG:
+    if: ${{ fromJson(inputs.branch).jobs.WINDOWS }}
+    name: "WINDOWS_X64_ZTS_CLANG"
+    runs-on: windows-2022
+    env:
+      PHP_BUILD_CACHE_BASE_DIR: C:\build-cache
+      PHP_BUILD_OBJ_DIR: C:\obj
+      PHP_BUILD_CACHE_SDK_DIR: C:\build-cache\sdk
+      PHP_BUILD_SDK_BRANCH: php-sdk-2.5.0
+      PHP_BUILD_CRT: ${{ fromJson(inputs.branch).jobs.WINDOWS.config.vs_crt_version }}
+      PLATFORM: x64
+      THREAD_SAFE: "1"
+      INTRINSICS: "AVX2"
+      PARALLEL: -j2
+      OPCACHE: "1"
+      CLANG_TOOLSET: "1"
+    steps:
+      - name: git config
+        run: git config --global core.autocrlf false && git config --global core.eol lf
+      - name: git checkout
+        uses: actions/checkout@v6
+        with:
+          ref: ${{ fromJson(inputs.branch).ref }}
+      - name: Setup
+        uses: ./.github/actions/setup-windows
+      - name: Build
+        run: .github/scripts/windows/build.bat
+      - name: Test
+        run: .github/scripts/windows/test.bat
   FREEBSD:
     if: ${{ fromJson(inputs.branch).jobs.FREEBSD }}
     strategy:
diff --git a/TSRM/TSRM.h b/TSRM/TSRM.h
index 80d6cbad04435..135872f79ecc3 100644
--- a/TSRM/TSRM.h
+++ b/TSRM/TSRM.h
@@ -175,9 +175,14 @@ TSRM_API bool tsrm_is_managed_thread(void);
 #define TSRMG_BULK_STATIC(id, type)	((type) (*((void ***) TSRMLS_CACHE))[TSRM_UNSHUFFLE_RSRC_ID(id)])
 #define TSRMG_FAST_STATIC(offset, type, element)	(TSRMG_FAST_BULK_STATIC(offset, type)->element)
 #define TSRMG_FAST_BULK_STATIC(offset, type)	((type) (((char*) TSRMLS_CACHE)+(offset)))
+#if defined(__cplusplus) && defined(__clang__)
+#define TSRMLS_MAIN_CACHE_EXTERN() extern "C" { extern TSRM_TLS void *TSRMLS_CACHE TSRM_TLS_MODEL_ATTR; }
+#define TSRMLS_CACHE_EXTERN() extern "C" { extern TSRM_TLS void *TSRMLS_CACHE; }
+#else
 #define TSRMLS_MAIN_CACHE_EXTERN() extern TSRM_TLS void *TSRMLS_CACHE TSRM_TLS_MODEL_ATTR;
-#define TSRMLS_MAIN_CACHE_DEFINE() TSRM_TLS void *TSRMLS_CACHE TSRM_TLS_MODEL_ATTR = NULL;
 #define TSRMLS_CACHE_EXTERN() extern TSRM_TLS void *TSRMLS_CACHE;
+#endif
+#define TSRMLS_MAIN_CACHE_DEFINE() TSRM_TLS void *TSRMLS_CACHE TSRM_TLS_MODEL_ATTR = NULL;
 #define TSRMLS_CACHE_DEFINE() TSRM_TLS void *TSRMLS_CACHE = NULL;
 #define TSRMLS_CACHE_UPDATE() TSRMLS_CACHE = tsrm_get_ls_cache()
 #define TSRMLS_CACHE _tsrm_ls_cache
diff --git a/Zend/zend_atomic.c b/Zend/zend_atomic.c
index 5f6a7793beeab..4151e5e539de2 100644
--- a/Zend/zend_atomic.c
+++ b/Zend/zend_atomic.c
@@ -57,7 +57,7 @@ ZEND_API void zend_atomic_int_store(zend_atomic_int *obj, int desired) {
 	zend_atomic_int_store_ex(obj, desired);
 }
 
-#if defined(ZEND_WIN32) || defined(HAVE_SYNC_ATOMICS)
+#if (defined(ZEND_WIN32) || defined(HAVE_SYNC_ATOMICS)) && !defined(HAVE_C11_ATOMICS)
 /* On these platforms it is non-const due to underlying APIs. */
 ZEND_API bool zend_atomic_bool_load(zend_atomic_bool *obj) {
 	return zend_atomic_bool_load_ex(obj);
diff --git a/Zend/zend_atomic.h b/Zend/zend_atomic.h
index 56422a721fdba..bcbc6681c9289 100644
--- a/Zend/zend_atomic.h
+++ b/Zend/zend_atomic.h
@@ -39,7 +39,7 @@
  * and alignment purposes.
  */
 
-#if defined(ZEND_WIN32) || defined(HAVE_SYNC_ATOMICS)
+#if (defined(ZEND_WIN32) || defined(HAVE_SYNC_ATOMICS)) && !defined(HAVE_C11_ATOMICS)
 typedef struct zend_atomic_bool_s {
 	volatile char value;
 } zend_atomic_bool;
@@ -68,7 +68,7 @@ typedef struct zend_atomic_int_s {
 
 BEGIN_EXTERN_C()
 
-#ifdef ZEND_WIN32
+#if defined(ZEND_WIN32) && !defined(HAVE_C11_ATOMICS)
 
 #ifndef InterlockedExchange8
 #define InterlockedExchange8 _InterlockedExchange8
@@ -123,7 +123,7 @@ static zend_always_inline bool zend_atomic_int_compare_exchange_ex(zend_atomic_i
 	}
 }
 
-/* On this platform it is non-const due to Iterlocked API*/
+/* On this platform it is non-const due to Interlocked API */
 static zend_always_inline bool zend_atomic_bool_load_ex(zend_atomic_bool *obj) {
 	/* Or'ing with false won't change the value. */
 	return InterlockedOr8(&obj->value, false);
@@ -376,7 +376,7 @@ ZEND_API bool zend_atomic_int_compare_exchange(zend_atomic_int *obj, int *expect
 ZEND_API void zend_atomic_bool_store(zend_atomic_bool *obj, bool desired);
 ZEND_API void zend_atomic_int_store(zend_atomic_int *obj, int desired);
 
-#if defined(ZEND_WIN32) || defined(HAVE_SYNC_ATOMICS)
+#if (defined(ZEND_WIN32) && !defined(HAVE_C11_ATOMICS)) || defined(HAVE_SYNC_ATOMICS)
 /* On these platforms it is non-const due to underlying APIs. */
 ZEND_API bool zend_atomic_bool_load(zend_atomic_bool *obj);
 ZEND_API int zend_atomic_int_load(zend_atomic_int *obj);
diff --git a/win32/build/confutils.js b/win32/build/confutils.js
index 0930a86b741ca..8a12e2690f759 100644
--- a/win32/build/confutils.js
+++ b/win32/build/confutils.js
@@ -3306,7 +3306,7 @@ function toolset_setup_common_cflags()
 
 		ADD_FLAG("CFLAGS", "/Zc:wchar_t");
 	} else if (CLANG_TOOLSET) {
-		ADD_FLAG("CFLAGS", "-Wno-deprecated-declarations");
+		ADD_FLAG("CFLAGS", "-Wno-deprecated-declarations -Wno-microsoft-enum-forward-reference");
 		if (TARGET_ARCH == 'x86') {
 			ADD_FLAG('CFLAGS', '-m32');
 		} else {
@@ -3319,7 +3319,11 @@ function toolset_setup_common_cflags()
 
 		var vc_ver = probe_binary(PATH_PROG('cl', null));
 		ADD_FLAG("CFLAGS"," -fms-compatibility -fms-compatibility-version=" + vc_ver + " -fms-extensions");
-	}
+
+        if (CLANGVERS >= 1900 && (TARGET_ARCH === 'x64' || TARGET_ARCH === 'arm64')) {
+            AC_DEFINE('HAVE_PRESERVE_NONE', 1, 'Whether the compiler supports __attribute__((preserve_none))');
+        }
+    }
 
 	if (!CLANG_TOOLSET) {
 		/* clang uses __builtin_*() instead */