diff --git a/appveyor.yml b/appveyor.yml
index 17215931..24437be9 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -52,6 +52,15 @@
       PLATFORM: "Win32"
       CONFIGURATION: "Release"
 
+    - COMPILER: "clang-cl"
+      HOST:     "cmake-visual"
+      PLATFORM: "x64"
+      CONFIGURATION: "Release"
+      CMAKE_GENERATOR: "Visual Studio 15 2017"
+      CMAKE_GENERATOR_PLATFORM: "x64"
+      CMAKE_GENERATOR_TOOLSET: "LLVM"
+      APPVEYOR_BUILD_WORKER_IMAGE: "Visual Studio 2017"
+
   install:
   - ECHO Installing %COMPILER% %PLATFORM% %CONFIGURATION%
   - SET PATH_ORIGINAL=%PATH%
@@ -154,6 +163,15 @@
       COPY build\VS2010\bin\%PLATFORM%_%CONFIGURATION%\fuzzer.exe tests\fuzzer_VS2015_%PLATFORM%_%CONFIGURATION%.exe &&
       COPY build\VS2010\bin\%PLATFORM%_%CONFIGURATION%\*.exe tests\
     )
+  - if [%HOST%]==[cmake-visual] (
+      ECHO *** &&
+      ECHO *** Building %CMAKE_GENERATOR% ^(%CMAKE_GENERATOR_TOOLSET%^) %PLATFORM%\%CONFIGURATION% &&
+      PUSHD build\cmake &&
+      cmake -DBUILD_TESTING=ON . &&
+      cmake --build . --config %CONFIGURATION% -j4 &&
+      POPD &&
+      ECHO ***
+    )
 
   test_script:
   - ECHO Testing %COMPILER% %PLATFORM% %CONFIGURATION%
@@ -223,6 +241,15 @@
       PLATFORM: "Win32"
       CONFIGURATION: "Release"
 
+    - COMPILER: "clang-cl"
+      HOST:     "cmake-visual"
+      PLATFORM: "x64"
+      CONFIGURATION: "Release"
+      CMAKE_GENERATOR: "Visual Studio 15 2017"
+      CMAKE_GENERATOR_PLATFORM: "x64"
+      CMAKE_GENERATOR_TOOLSET: "LLVM"
+      APPVEYOR_BUILD_WORKER_IMAGE: "Visual Studio 2017"
+
   install:
   - ECHO Installing %COMPILER% %PLATFORM% %CONFIGURATION%
   - SET PATH_ORIGINAL=%PATH%
@@ -281,6 +308,15 @@
       COPY build\VS2010\bin\%PLATFORM%_%CONFIGURATION%\fuzzer.exe tests\fuzzer_VS2015_%PLATFORM%_%CONFIGURATION%.exe &&
       COPY build\VS2010\bin\%PLATFORM%_%CONFIGURATION%\*.exe tests\
     )
+  - if [%HOST%]==[cmake-visual] (
+      ECHO *** &&
+      ECHO *** Building %CMAKE_GENERATOR% ^(%CMAKE_GENERATOR_TOOLSET%^) %PLATFORM%\%CONFIGURATION% &&
+      PUSHD build\cmake &&
+      cmake -DBUILD_TESTING=ON . &&
+      cmake --build . --config %CONFIGURATION% -j4 &&
+      POPD &&
+      ECHO ***
+    )
 
 
   test_script:
diff --git a/build/cmake/CMakeModules/AddZstdCompilationFlags.cmake b/build/cmake/CMakeModules/AddZstdCompilationFlags.cmake
index 62389717..e23b9d60 100644
--- a/build/cmake/CMakeModules/AddZstdCompilationFlags.cmake
+++ b/build/cmake/CMakeModules/AddZstdCompilationFlags.cmake
@@ -26,7 +26,12 @@ macro(ADD_ZSTD_COMPILATION_FLAGS)
         EnableCompilerFlag("-std=c++11" false true)
         #Set c99 by default
         EnableCompilerFlag("-std=c99" true false)
-        EnableCompilerFlag("-Wall" true true)
+        if (CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND MSVC)
+            # clang-cl normally maps -Wall to -Weverything.
+            EnableCompilerFlag("/clang:-Wall" true true)
+        else ()
+            EnableCompilerFlag("-Wall" true true)
+        endif ()
         EnableCompilerFlag("-Wextra" true true)
         EnableCompilerFlag("-Wundef" true true)
         EnableCompilerFlag("-Wshadow" true true)