diff --git a/test_conformance/compiler/CMakeLists.txt b/test_conformance/compiler/CMakeLists.txt
index 5806469a98..e703471d28 100644
--- a/test_conformance/compiler/CMakeLists.txt
+++ b/test_conformance/compiler/CMakeLists.txt
@@ -1,9 +1,5 @@
 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/compiler/test_preprocessor.cpp b/test_conformance/compiler/test_preprocessor.cpp
index 7308950aee..3c5c2045ea 100644
--- a/test_conformance/compiler/test_preprocessor.cpp
+++ b/test_conformance/compiler/test_preprocessor.cpp
@@ -89,7 +89,7 @@ int test_preprocessor_define_udef(cl_device_id deviceID, cl_context context, cl_
   error = clEnqueueWriteBuffer(queue, buffer[0], CL_TRUE, 0, num_elements*sizeof(cl_int), srcData, 0, NULL, NULL);
   test_error(error, "clEnqueueWriteBuffer failed");
 
-  size_t threads[3] = {num_elements, 0, 0};
+  size_t threads[3] = { (size_t)num_elements, 0, 0 };
   error = clEnqueueNDRangeKernel(queue, kernel, 1, NULL, threads, NULL, 0, NULL, NULL);
   test_error(error, "clEnqueueNDRangeKernel failed");
 
@@ -175,7 +175,7 @@ int test_preprocessor_include(cl_device_id deviceID, cl_context context, cl_comm
   error = clSetKernelArg(kernel, 1, sizeof(buffer[1]), &buffer[1]);
   test_error(error, "clSetKernelArg failed");
 
-  size_t threads[3] = {num_elements, 0, 0};
+  size_t threads[3] = { (size_t)num_elements, 0, 0 };
   error = clEnqueueNDRangeKernel(queue, kernel, 1, NULL, threads, NULL, 0, NULL, NULL);
   test_error(error, "clEnqueueNDRangeKernel failed");
 
@@ -272,7 +272,7 @@ int test_preprocessor_line_error(cl_device_id deviceID, cl_context context, cl_c
   error = clSetKernelArg(kernel, 0, sizeof(buffer[0]), &buffer[0]);
   test_error(error, "clSetKernelArg failed");
 
-  size_t threads[3] = {num_elements, 0, 0};
+  size_t threads[3] = { (size_t)num_elements, 0, 0 };
   error = clEnqueueNDRangeKernel(queue, kernel, 1, NULL, threads, NULL, 0, NULL, NULL);
   test_error(error, "clEnqueueNDRangeKernel failed");
 
@@ -313,7 +313,7 @@ int test_preprocessor_pragma(cl_device_id deviceID, cl_context context, cl_comma
   error = clSetKernelArg(kernel, 0, sizeof(buffer[0]), &buffer[0]);
   test_error(error, "clSetKernelArg failed");
 
-  size_t threads[3] = {num_elements, 0, 0};
+  size_t threads[3] = { (size_t)num_elements, 0, 0 };
   error = clEnqueueNDRangeKernel(queue, kernel, 1, NULL, threads, NULL, 0, NULL, NULL);
   test_error(error, "clEnqueueNDRangeKernel failed");
 
diff --git a/test_conformance/spirv_new/test_op_composite_construct.cpp b/test_conformance/spirv_new/test_op_composite_construct.cpp
index 7ca8762611..db4a66bf21 100644
--- a/test_conformance/spirv_new/test_op_composite_construct.cpp
+++ b/test_conformance/spirv_new/test_op_composite_construct.cpp
@@ -68,7 +68,7 @@ TEST_SPIRV_FUNC(op_composite_construct_struct)
     typedef AbstractStruct2<int, char> CustomType1;
     typedef AbstractStruct2<cl_int2, CustomType1> CustomType2;
 
-    CustomType1 value1 = {2100483600, 128};
+    CustomType1 value1 = { 2100483600, (char)128 };
     cl_int2 intvals = { { 2100480000, 2100480000 } };
     CustomType2 value2 = {intvals, value1};
 
diff --git a/test_conformance/spirv_new/test_op_constant.cpp b/test_conformance/spirv_new/test_op_constant.cpp
index c026fd42ff..c3b7c58fbb 100644
--- a/test_conformance/spirv_new/test_op_constant.cpp
+++ b/test_conformance/spirv_new/test_op_constant.cpp
@@ -122,7 +122,7 @@ TEST_SPIRV_FUNC(op_constant_struct_int_float_simple)
 
 TEST_SPIRV_FUNC(op_constant_struct_int_char_simple)
 {
-    AbstractStruct2<int, char> value = {2100483600, 128};
+    AbstractStruct2<int, char> value = { 2100483600, (char)128 };
     std::vector<AbstractStruct2<int, char> > results(256, value);
     return test_constant(deviceID, context, queue, "constant_struct_int_char_simple", results);
 }
@@ -132,7 +132,7 @@ TEST_SPIRV_FUNC(op_constant_struct_struct_simple)
     typedef AbstractStruct2<int, char> CustomType1;
     typedef AbstractStruct2<cl_int2, CustomType1> CustomType2;
 
-    CustomType1 value1 = {2100483600, 128};
+    CustomType1 value1 = { 2100483600, (char)128 };
     cl_int2 intvals = { { 2100480000, 2100480000 } };
     CustomType2 value2 = {intvals, value1};
 
diff --git a/test_conformance/spirv_new/test_op_copy_object.cpp b/test_conformance/spirv_new/test_op_copy_object.cpp
index b012960efc..019b603323 100644
--- a/test_conformance/spirv_new/test_op_copy_object.cpp
+++ b/test_conformance/spirv_new/test_op_copy_object.cpp
@@ -118,7 +118,7 @@ TEST_SPIRV_FUNC(op_copy_struct_int_float_simple)
 
 TEST_SPIRV_FUNC(op_copy_struct_int_char_simple)
 {
-    AbstractStruct2<int, char> value = {2100483600, 128};
+    AbstractStruct2<int, char> value = { 2100483600, (char)128 };
     std::vector<AbstractStruct2<int, char> > results(256, value);
     return test_copy(deviceID, context, queue, "copy_struct_int_char_simple", results);
 }
@@ -128,7 +128,7 @@ TEST_SPIRV_FUNC(op_copy_struct_struct_simple)
     typedef AbstractStruct2<int, char> CustomType1;
     typedef AbstractStruct2<cl_int2, CustomType1> CustomType2;
 
-    CustomType1 value1 = {2100483600, 128};
+    CustomType1 value1 = { 2100483600, (char)128 };
     cl_int2 intvals = { { 2100480000, 2100480000 } };
     CustomType2 value2 = {intvals, value1};