diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5cfef6b332..6037c6b888 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -104,7 +104,6 @@ if(CMAKE_COMPILER_IS_GNUCC OR "${CMAKE_CXX_COMPILER_ID}" MATCHES "(Apple)?Clang"
         # Enable more warnings if not doing a release build.
         add_cxx_flag_if_supported(-Wall)
     endif()
-    add_cxx_flag_if_supported(-Wno-narrowing)
     add_cxx_flag_if_supported(-Wno-format)
     add_cxx_flag_if_supported(-Wno-error=cpp) # Allow #warning directive
     add_cxx_flag_if_supported(-Wno-unknown-pragmas) # Issue #785
diff --git a/test_common/harness/kernelHelpers.cpp b/test_common/harness/kernelHelpers.cpp
index 633b05e5c7..7aadda1b73 100644
--- a/test_common/harness/kernelHelpers.cpp
+++ b/test_common/harness/kernelHelpers.cpp
@@ -1,5 +1,5 @@
 //
-// Copyright (c) 2017 The Khronos Group Inc.
+// Copyright (c) 2017, 2021 The Khronos Group Inc.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -1626,7 +1626,7 @@ Version get_device_cl_c_version(cl_device_id device)
                                  &opencl_c_version_size_in_bytes);
     test_error_ret(error,
                    "clGetDeviceInfo failed for CL_DEVICE_OPENCL_C_VERSION\n",
-                   (Version{ -1, 0 }));
+                   (Version{ 0, 0 }));
 
     std::string opencl_c_version(opencl_c_version_size_in_bytes, '\0');
     error =
@@ -1635,13 +1635,13 @@ Version get_device_cl_c_version(cl_device_id device)
 
     test_error_ret(error,
                    "clGetDeviceInfo failed for CL_DEVICE_OPENCL_C_VERSION\n",
-                   (Version{ -1, 0 }));
+                   (Version{ 0, 0 }));
 
     // Scrape out the major, minor pair from the string.
     auto major = opencl_c_version[opencl_c_version.find('.') - 1];
     auto minor = opencl_c_version[opencl_c_version.find('.') + 1];
 
-    return Version{ major - '0', minor - '0' };
+    return Version{ (uint)(major - '0'), (uint)(minor - '0') };
 }
 
 Version get_device_latest_cl_c_version(cl_device_id device)
@@ -1659,7 +1659,7 @@ Version get_device_latest_cl_c_version(cl_device_id device)
                             &opencl_c_all_versions_size_in_bytes);
         test_error_ret(
             error, "clGetDeviceInfo failed for CL_DEVICE_OPENCL_C_ALL_VERSIONS",
-            (Version{ -1, 0 }));
+            (Version{ 0, 0 }));
         std::vector<cl_name_version> name_versions(
             opencl_c_all_versions_size_in_bytes / sizeof(cl_name_version));
         error = clGetDeviceInfo(device, CL_DEVICE_OPENCL_C_ALL_VERSIONS,
@@ -1667,7 +1667,7 @@ Version get_device_latest_cl_c_version(cl_device_id device)
                                 name_versions.data(), nullptr);
         test_error_ret(
             error, "clGetDeviceInfo failed for CL_DEVICE_OPENCL_C_ALL_VERSIONS",
-            (Version{ -1, 0 }));
+            (Version{ 0, 0 }));
 
         Version max_supported_cl_c_version{};
         for (const auto &name_version : name_versions)
@@ -1695,7 +1695,7 @@ Version get_max_OpenCL_C_for_context(cl_context context)
     auto error = clGetContextInfo(context, CL_CONTEXT_DEVICES, 0, nullptr,
                                   &devices_size_in_bytes);
     test_error_ret(error, "clGetDeviceInfo failed for CL_CONTEXT_DEVICES",
-                   (Version{ -1, 0 }));
+                   (Version{ 0, 0 }));
     std::vector<cl_device_id> devices(devices_size_in_bytes
                                       / sizeof(cl_device_id));
     error = clGetContextInfo(context, CL_CONTEXT_DEVICES, devices_size_in_bytes,
diff --git a/test_common/harness/rounding_mode.cpp b/test_common/harness/rounding_mode.cpp
index 191c04d929..cb13db6b47 100644
--- a/test_common/harness/rounding_mode.cpp
+++ b/test_common/harness/rounding_mode.cpp
@@ -1,5 +1,5 @@
 //
-// Copyright (c) 2017 The Khronos Group Inc.
+// Copyright (c) 2017, 2021 The Khronos Group Inc.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -240,7 +240,7 @@ void UnFlushToZero(void *p)
 #if defined(__i386__) || defined(__x86_64__) || defined(_MSC_VER)
     union {
         void *p;
-        int i;
+        uint i;
     } u = { p };
     _mm_setcsr(u.i);
 #elif defined(__arm__) || defined(__aarch64__)
diff --git a/test_common/harness/testHarness.h b/test_common/harness/testHarness.h
index b266db80f4..fd36bda0d4 100644
--- a/test_common/harness/testHarness.h
+++ b/test_common/harness/testHarness.h
@@ -1,5 +1,5 @@
 //
-// Copyright (c) 2017-2019 The Khronos Group Inc.
+// Copyright (c) 2017-2021 The Khronos Group Inc.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -25,7 +25,7 @@
 class Version {
 public:
     Version(): m_major(0), m_minor(0) {}
-    Version(int major, int minor): m_major(major), m_minor(minor) {}
+    Version(uint major, uint minor): m_major(major), m_minor(minor) {}
     bool operator>(const Version &rhs) const { return to_int() > rhs.to_int(); }
     bool operator<(const Version &rhs) const { return to_int() < rhs.to_int(); }
     bool operator<=(const Version &rhs) const
@@ -49,8 +49,8 @@ class Version {
     }
 
 private:
-    int m_major;
-    int m_minor;
+    uint m_major;
+    uint m_minor;
 };
 
 Version get_device_cl_version(cl_device_id device);
diff --git a/test_conformance/CMakeLists.txt b/test_conformance/CMakeLists.txt
index 1f1970afd8..498f3a3d06 100644
--- a/test_conformance/CMakeLists.txt
+++ b/test_conformance/CMakeLists.txt
@@ -1,6 +1,10 @@
 # Remember current source directory (`test_conformance').
 set( CLConf_Install_Base_Dir "${CMAKE_CURRENT_SOURCE_DIR}" )
 
+if(CMAKE_COMPILER_IS_GNUCC OR "${CMAKE_CXX_COMPILER_ID}" MATCHES "(Apple)?Clang")
+    add_cxx_flag_if_supported(-Wno-narrowing)
+endif()
+
 set(HARNESS_LIB harness)
 
 add_subdirectory( allocations )