diff --git a/test_conformance/CMakeLists.txt b/test_conformance/CMakeLists.txt
index 4685606b71..87d68597f0 100644
--- a/test_conformance/CMakeLists.txt
+++ b/test_conformance/CMakeLists.txt
@@ -1,10 +1,6 @@
 # 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 )
diff --git a/test_conformance/api/test_queries.cpp b/test_conformance/api/test_queries.cpp
index 469a19349a..23b0cc87aa 100644
--- a/test_conformance/api/test_queries.cpp
+++ b/test_conformance/api/test_queries.cpp
@@ -152,7 +152,7 @@ int sampler_param_test(cl_sampler sampler, cl_sampler_info param_name,
     return 0;
 }
 
-static cl_int normalized_coord_values[] = { CL_TRUE, CL_FALSE };
+static cl_bool normalized_coord_values[] = { CL_TRUE, CL_FALSE };
 static cl_addressing_mode addressing_mode_values[] = {
     CL_ADDRESS_NONE, CL_ADDRESS_CLAMP_TO_EDGE, CL_ADDRESS_CLAMP,
     CL_ADDRESS_REPEAT, CL_ADDRESS_MIRRORED_REPEAT
diff --git a/test_conformance/atomics/test_atomics.cpp b/test_conformance/atomics/test_atomics.cpp
index 34b34ed38a..83efe68efb 100644
--- a/test_conformance/atomics/test_atomics.cpp
+++ b/test_conformance/atomics/test_atomics.cpp
@@ -1011,8 +1011,15 @@ cl_long test_atomic_and_result_long( size_t size, cl_long *startRefValues, size_
 
 int test_atomic_and(cl_device_id deviceID, cl_context context, cl_command_queue queue, int num_elements)
 {
-    TestFns set = { 0xffffffff, 0xffffffffffffffffLL, test_bitwise_num_results,
-        test_atomic_and_result_int, NULL, NULL, test_atomic_and_result_long, NULL, NULL };
+    TestFns set = { (int)0xffffffff,
+                    (long long)0xffffffffffffffffLL,
+                    test_bitwise_num_results,
+                    test_atomic_and_result_int,
+                    NULL,
+                    NULL,
+                    test_atomic_and_result_long,
+                    NULL,
+                    NULL };
 
     if( test_atomic_function_set( deviceID, context, queue, num_elements, atom_and_core, set, true, /*matchGroupSize*/ false, /*usingAtomicPrefix*/ false  ) != 0 )
         return -1;
diff --git a/test_conformance/basic/CMakeLists.txt b/test_conformance/basic/CMakeLists.txt
index c5c4b5f0cc..d2e5ef51cc 100644
--- a/test_conformance/basic/CMakeLists.txt
+++ b/test_conformance/basic/CMakeLists.txt
@@ -1,5 +1,9 @@
 set(MODULE_NAME BASIC)
 
+if(CMAKE_COMPILER_IS_GNUCC OR "${CMAKE_CXX_COMPILER_ID}" MATCHES "(Apple)?Clang")
+    add_cxx_flag_if_supported(-Wno-narrowing)
+endif()
+
 set(${MODULE_NAME}_SOURCES
     main.cpp
     test_fpmath_float.cpp test_fpmath_float2.cpp test_fpmath_float4.cpp
diff --git a/test_conformance/compiler/CMakeLists.txt b/test_conformance/compiler/CMakeLists.txt
index e703471d28..5806469a98 100644
--- a/test_conformance/compiler/CMakeLists.txt
+++ b/test_conformance/compiler/CMakeLists.txt
@@ -1,5 +1,9 @@
 set(MODULE_NAME COMPILER)
 
+if(CMAKE_COMPILER_IS_GNUCC OR "${CMAKE_CXX_COMPILER_ID}" MATCHES "(Apple)?Clang")
+    add_cxx_flag_if_supported(-Wno-narrowing)
+endif()
+
 set(${MODULE_NAME}_SOURCES
     main.cpp
     test_build_helpers.cpp
diff --git a/test_conformance/computeinfo/main.cpp b/test_conformance/computeinfo/main.cpp
index 4860b44561..883abfe4c6 100644
--- a/test_conformance/computeinfo/main.cpp
+++ b/test_conformance/computeinfo/main.cpp
@@ -35,11 +35,11 @@ typedef struct
 } device_info;
 
 device_info device_infos[] = {
-    { CL_DEVICE_TYPE_DEFAULT, "CL_DEVICE_TYPE_DEFAULT", -1, NULL },
-    { CL_DEVICE_TYPE_CPU, "CL_DEVICE_TYPE_CPU", -1, NULL },
-    { CL_DEVICE_TYPE_GPU, "CL_DEVICE_TYPE_GPU", -1, NULL },
-    { CL_DEVICE_TYPE_ACCELERATOR, "CL_DEVICE_TYPE_ACCELERATOR", -1, NULL },
-    { CL_DEVICE_TYPE_ALL, "CL_DEVICE_TYPE_ALL", -1, NULL },
+    { CL_DEVICE_TYPE_DEFAULT, "CL_DEVICE_TYPE_DEFAULT", 0, NULL },
+    { CL_DEVICE_TYPE_CPU, "CL_DEVICE_TYPE_CPU", 0, NULL },
+    { CL_DEVICE_TYPE_GPU, "CL_DEVICE_TYPE_GPU", 0, NULL },
+    { CL_DEVICE_TYPE_ACCELERATOR, "CL_DEVICE_TYPE_ACCELERATOR", 0, NULL },
+    { CL_DEVICE_TYPE_ALL, "CL_DEVICE_TYPE_ALL", 0, NULL },
 };
 
 // config types
diff --git a/test_conformance/conversions/CMakeLists.txt b/test_conformance/conversions/CMakeLists.txt
index 523b6ead97..a4bef70b73 100644
--- a/test_conformance/conversions/CMakeLists.txt
+++ b/test_conformance/conversions/CMakeLists.txt
@@ -1,5 +1,9 @@
 set(MODULE_NAME CONVERSIONS)
 
+if(CMAKE_COMPILER_IS_GNUCC OR "${CMAKE_CXX_COMPILER_ID}" MATCHES "(Apple)?Clang")
+    add_cxx_flag_if_supported(-Wno-narrowing)
+endif()
+
 set (${MODULE_NAME}_SOURCES
       Sleep.cpp test_conversions.cpp basic_test_conversions.cpp
 )
diff --git a/test_conformance/device_execution/execute_block.cpp b/test_conformance/device_execution/execute_block.cpp
index e5b13eff7e..d2f4776313 100644
--- a/test_conformance/device_execution/execute_block.cpp
+++ b/test_conformance/device_execution/execute_block.cpp
@@ -1016,7 +1016,7 @@ int test_execute_block(cl_device_id device, cl_context context, cl_command_queue
     size_t ret_len;
     cl_int n, err_ret, res = 0;
     clCommandQueueWrapper dev_queue;
-    cl_int kernel_results[MAX_GWS] = {0xDEADBEEF};
+    cl_int kernel_results[MAX_GWS] = { (cl_int)0xDEADBEEF };
 
     size_t max_local_size = 1;
     err_ret = clGetDeviceInfo(device, CL_DEVICE_MAX_WORK_GROUP_SIZE, sizeof(max_local_size), &max_local_size, &ret_len);
diff --git a/test_conformance/device_partition/test_device_partition.cpp b/test_conformance/device_partition/test_device_partition.cpp
index f9952ec8ad..ce5c56628f 100644
--- a/test_conformance/device_partition/test_device_partition.cpp
+++ b/test_conformance/device_partition/test_device_partition.cpp
@@ -355,7 +355,8 @@ int test_device_set(size_t deviceCount, size_t queueCount, cl_device_id *devices
 }
 
 
-int init_device_partition_test(cl_device_id parentDevice, cl_uint &maxComputeUnits, cl_uint &maxSubDevices)
+int init_device_partition_test(cl_device_id parentDevice,
+                               cl_uint &maxComputeUnits, cl_uint &maxSubDevices)
 {
     int err = clGetDeviceInfo(parentDevice, CL_DEVICE_MAX_COMPUTE_UNITS, sizeof(maxComputeUnits), &maxComputeUnits, NULL);
     test_error( err, "Unable to get maximal number of compute units" );
@@ -451,14 +452,21 @@ int test_partition_of_device(cl_device_id deviceID, cl_context context, cl_comma
 
 #define PROPERTY_TYPES 8
     cl_device_partition_property partitionProp[PROPERTY_TYPES][5] = {
-        { CL_DEVICE_PARTITION_EQUALLY, maxComputeUnits / 2, 0, 0, 0 } ,
-        { CL_DEVICE_PARTITION_BY_COUNTS, 1, maxComputeUnits - 1, CL_DEVICE_PARTITION_BY_COUNTS_LIST_END, 0 } ,
-        { CL_DEVICE_PARTITION_BY_AFFINITY_DOMAIN, CL_DEVICE_AFFINITY_DOMAIN_NUMA, 0, 0, 0 } ,
-        { CL_DEVICE_PARTITION_BY_AFFINITY_DOMAIN, CL_DEVICE_AFFINITY_DOMAIN_L4_CACHE, 0, 0, 0 } ,
-        { CL_DEVICE_PARTITION_BY_AFFINITY_DOMAIN, CL_DEVICE_AFFINITY_DOMAIN_L3_CACHE, 0, 0, 0 } ,
-        { CL_DEVICE_PARTITION_BY_AFFINITY_DOMAIN, CL_DEVICE_AFFINITY_DOMAIN_L2_CACHE, 0, 0, 0 } ,
-        { CL_DEVICE_PARTITION_BY_AFFINITY_DOMAIN, CL_DEVICE_AFFINITY_DOMAIN_L1_CACHE, 0, 0, 0 } ,
-        { CL_DEVICE_PARTITION_BY_AFFINITY_DOMAIN, CL_DEVICE_AFFINITY_DOMAIN_NEXT_PARTITIONABLE, 0, 0, 0 }
+        { CL_DEVICE_PARTITION_EQUALLY, (cl_int)maxComputeUnits / 2, 0, 0, 0 },
+        { CL_DEVICE_PARTITION_BY_COUNTS, 1, (cl_int)maxComputeUnits - 1,
+          CL_DEVICE_PARTITION_BY_COUNTS_LIST_END, 0 },
+        { CL_DEVICE_PARTITION_BY_AFFINITY_DOMAIN,
+          CL_DEVICE_AFFINITY_DOMAIN_NUMA, 0, 0, 0 },
+        { CL_DEVICE_PARTITION_BY_AFFINITY_DOMAIN,
+          CL_DEVICE_AFFINITY_DOMAIN_L4_CACHE, 0, 0, 0 },
+        { CL_DEVICE_PARTITION_BY_AFFINITY_DOMAIN,
+          CL_DEVICE_AFFINITY_DOMAIN_L3_CACHE, 0, 0, 0 },
+        { CL_DEVICE_PARTITION_BY_AFFINITY_DOMAIN,
+          CL_DEVICE_AFFINITY_DOMAIN_L2_CACHE, 0, 0, 0 },
+        { CL_DEVICE_PARTITION_BY_AFFINITY_DOMAIN,
+          CL_DEVICE_AFFINITY_DOMAIN_L1_CACHE, 0, 0, 0 },
+        { CL_DEVICE_PARTITION_BY_AFFINITY_DOMAIN,
+          CL_DEVICE_AFFINITY_DOMAIN_NEXT_PARTITIONABLE, 0, 0, 0 }
     };
 
     // loop thru each type, creating sub-devices for each type
diff --git a/test_conformance/integer_ops/CMakeLists.txt b/test_conformance/integer_ops/CMakeLists.txt
index a045ef81c1..6285a70982 100644
--- a/test_conformance/integer_ops/CMakeLists.txt
+++ b/test_conformance/integer_ops/CMakeLists.txt
@@ -1,5 +1,9 @@
 set(MODULE_NAME INTEGER_OPS)
 
+if(CMAKE_COMPILER_IS_GNUCC OR "${CMAKE_CXX_COMPILER_ID}" MATCHES "(Apple)?Clang")
+    add_cxx_flag_if_supported(-Wno-narrowing)
+endif()
+
 set(${MODULE_NAME}_SOURCES
     main.cpp
     test_int_basic_ops.cpp
diff --git a/test_conformance/non_uniform_work_group/CMakeLists.txt b/test_conformance/non_uniform_work_group/CMakeLists.txt
index 30c3a84610..7db5bcbb11 100644
--- a/test_conformance/non_uniform_work_group/CMakeLists.txt
+++ b/test_conformance/non_uniform_work_group/CMakeLists.txt
@@ -1,5 +1,9 @@
 set(MODULE_NAME NON_UNIFORM_WORK_GROUP)
 
+if(CMAKE_COMPILER_IS_GNUCC OR "${CMAKE_CXX_COMPILER_ID}" MATCHES "(Apple)?Clang")
+    add_cxx_flag_if_supported(-Wno-narrowing)
+endif()
+
 set(${MODULE_NAME}_SOURCES
     main.cpp
     test_advanced_2d.cpp
diff --git a/test_conformance/profiling/execute.cpp b/test_conformance/profiling/execute.cpp
index edfc043c06..21bd4e2c25 100644
--- a/test_conformance/profiling/execute.cpp
+++ b/test_conformance/profiling/execute.cpp
@@ -318,7 +318,7 @@ static int kernelFilter( cl_device_id device, cl_context context, cl_command_que
 
     // read output image
     size_t origin[3] = { 0, 0, 0 };
-    size_t region[3] = { w, h, 1 };
+    size_t region[3] = { (size_t)w, (size_t)h, 1 };
     err = clEnqueueReadImage( queue, memobjs[1], true, origin, region, 0, 0, outptr, 0, NULL, NULL);
     if( err != CL_SUCCESS ){
         print_error( err, "clReadImage failed\n" );
diff --git a/test_conformance/profiling/readImage.cpp b/test_conformance/profiling/readImage.cpp
index 9ba6b472e7..fd4da128e1 100644
--- a/test_conformance/profiling/readImage.cpp
+++ b/test_conformance/profiling/readImage.cpp
@@ -233,7 +233,7 @@ int read_image( cl_device_id device, cl_context context, cl_command_queue queue,
     }
 
     size_t origin[3] = { 0, 0, 0 };
-    size_t region[3] = { w, h, 1 };
+    size_t region[3] = { (size_t)w, (size_t)h, 1 };
     err = clEnqueueReadImage( queue, memobjs[0], false, origin, region, 0, 0, dst, 0, NULL, &readEvent );
     if( err != CL_SUCCESS ){
         print_error( err, "clReadImage2D failed" );
diff --git a/test_conformance/profiling/writeImage.cpp b/test_conformance/profiling/writeImage.cpp
index fbc8fbcdf1..096ed7a5e5 100644
--- a/test_conformance/profiling/writeImage.cpp
+++ b/test_conformance/profiling/writeImage.cpp
@@ -472,7 +472,7 @@ int write_image( cl_device_id device, cl_context context, cl_command_queue queue
     }
 
     size_t origin[3] = { 0, 0, 0 };
-    size_t region[3] = { w, h, 1 };
+    size_t region[3] = { (size_t)w, (size_t)h, 1 };
     err = clEnqueueWriteImage( queue, memobjs[0], false, origin, region, 0, 0, inptr, 0, NULL, &writeEvent );
     if( err != CL_SUCCESS ){
         clReleaseMemObject(memobjs[0]);
diff --git a/test_conformance/spir/main.cpp b/test_conformance/spir/main.cpp
index 3a18988c70..c36c3938d7 100644
--- a/test_conformance/spir/main.cpp
+++ b/test_conformance/spir/main.cpp
@@ -167,7 +167,8 @@ static void get_spir_version(cl_device_id device,
     {
         auto major = v[v.find('.') - 1];
         auto minor = v[v.find('.') + 1];
-        versions.push_back(Version{ major - '0', minor - '0' });
+        versions.push_back(
+            Version{ (cl_uint)(major - '0'), (cl_uint)(minor - '0') });
     }
 }
 
diff --git a/test_conformance/spirv_new/CMakeLists.txt b/test_conformance/spirv_new/CMakeLists.txt
index 7500571d07..13d8bc7426 100644
--- a/test_conformance/spirv_new/CMakeLists.txt
+++ b/test_conformance/spirv_new/CMakeLists.txt
@@ -14,6 +14,10 @@
 set(MODULE_NAME SPIRV_NEW)
 set(CMAKE_CXX_STANDARD 11)
 
+if(CMAKE_COMPILER_IS_GNUCC OR "${CMAKE_CXX_COMPILER_ID}" MATCHES "(Apple)?Clang")
+    add_cxx_flag_if_supported(-Wno-narrowing)
+endif()
+
 file(GLOB SPIRV_NEW_SOURCES "*.cpp")
 
 set(TEST_HARNESS_SOURCES