Index: runtime/CMakeLists.txt
===================================================================
--- runtime/CMakeLists.txt
+++ runtime/CMakeLists.txt
@@ -41,6 +41,8 @@
   # Should assertions be enabled?  They are on by default.
   set(LIBOMP_ENABLE_ASSERTIONS TRUE CACHE BOOL
     "enable assertions?")
+  set(LIBOMP_ENABLE_WERROR TRUE CACHE BOOL
+    "Enable -Werror flags to turn warnings into errors for supporting compilers.")
   # CMAKE_BUILD_TYPE was not defined, set default to Release
   if(NOT CMAKE_BUILD_TYPE)
     set(CMAKE_BUILD_TYPE Release)
@@ -73,6 +75,7 @@
   endif ()
   set(LIBOMP_LIBDIR_SUFFIX ${LLVM_LIBDIR_SUFFIX})
   set(LIBOMP_ENABLE_ASSERTIONS ${LLVM_ENABLE_ASSERTIONS})
+  set(LIBOMP_ENABLE_WERROR ${LLVM_ENABLE_WERROR})
 endif()
 libomp_check_variable(LIBOMP_ARCH 32e x86_64 32 i386 arm ppc64 ppc64le aarch64 mic)
 
Index: runtime/cmake/LibompHandleFlags.cmake
===================================================================
--- runtime/cmake/LibompHandleFlags.cmake
+++ runtime/cmake/LibompHandleFlags.cmake
@@ -28,10 +28,25 @@
   set(flags_local)
   libomp_append(flags_local -std=c++11 LIBOMP_HAVE_STD_CPP11_FLAG)
   libomp_append(flags_local -fno-exceptions LIBOMP_HAVE_FNO_EXCEPTIONS_FLAG)
-  libomp_append(flags_local -Wsign-compare LIBOMP_HAVE_WSIGN_COMPARE_FLAG)
+  if(${LIBOMP_ENABLE_WERROR})
+    libomp_append(flags_local -Werror LIBOMP_HAVE_WERROR_FLAG)
+  endif()
+  libomp_append(flags_local -Wno-sign-compare LIBOMP_HAVE_WNO_SIGN_COMPARE_FLAG)
+  libomp_append(flags_local -Wno-unused-function LIBOMP_HAVE_WNO_UNUSED_FUNCTION_FLAG)
+  libomp_append(flags_local -Wno-unused-local-typedef LIBOMP_HAVE_WNO_UNUSED_LOCAL_TYPEDEF_FLAG)
   libomp_append(flags_local -Wno-unused-value LIBOMP_HAVE_WNO_UNUSED_VALUE_FLAG)
+  libomp_append(flags_local -Wno-unused-variable LIBOMP_HAVE_WNO_UNUSED_VARIABLE_FLAG)
   libomp_append(flags_local -Wno-switch LIBOMP_HAVE_WNO_SWITCH_FLAG)
+  libomp_append(flags_local -Wno-covered-switch-default LIBOMP_HAVE_WNO_COVERED_SWITCH_DEFAULT_FLAG)
   libomp_append(flags_local -Wno-deprecated-register LIBOMP_HAVE_WNO_DEPRECATED_REGISTER_FLAG)
+  libomp_append(flags_local -Wno-gnu-anonymous-struct LIBOMP_HAVE_WNO_GNU_ANONYMOUS_STRUCT_FLAG)
+  libomp_append(flags_local -Wno-unknown-pragmas LIBOMP_HAVE_WNO_UNKNOWN_PRAGMAS_FLAG)
+  libomp_append(flags_local -Wno-missing-field-initializers LIBOMP_HAVE_WNO_MISSING_FIELD_INITIALIZERS_FLAG)
+  libomp_append(flags_local -Wno-missing-braces LIBOMP_HAVE_WNO_MISSING_BRACES_FLAG)
+  libomp_append(flags_local -Wno-comment LIBOMP_HAVE_WNO_COMMENT_FLAG)
+  libomp_append(flags_local -Wno-self-assign LIBOMP_HAVE_WNO_SELF_ASSIGN_FLAG)
+  libomp_append(flags_local -Wno-vla-extension LIBOMP_HAVE_WNO_VLA_EXTENSION_FLAG)
+  libomp_append(flags_local -Wno-format-pedantic LIBOMP_HAVE_WNO_FORMAT_PEDANTIC_FLAG)
   libomp_append(flags_local /GS LIBOMP_HAVE_GS_FLAG)
   libomp_append(flags_local /EHsc LIBOMP_HAVE_EHSC_FLAG)
   libomp_append(flags_local /Oy- LIBOMP_HAVE_OY__FLAG)
Index: runtime/cmake/config-ix.cmake
===================================================================
--- runtime/cmake/config-ix.cmake
+++ runtime/cmake/config-ix.cmake
@@ -48,12 +48,25 @@
 check_cxx_compiler_flag(-std=c++11 LIBOMP_HAVE_STD_CPP11_FLAG)
 check_cxx_compiler_flag(-fno-exceptions LIBOMP_HAVE_FNO_EXCEPTIONS_FLAG)
 check_c_compiler_flag("-x c++" LIBOMP_HAVE_X_CPP_FLAG)
-check_cxx_compiler_flag(-Wunused-value LIBOMP_HAVE_WNO_UNUSED_VALUE_FLAG)
-check_cxx_compiler_flag(-Wswitch LIBOMP_HAVE_WNO_SWITCH_FLAG)
-check_cxx_compiler_flag(-Wdeprecated-register LIBOMP_HAVE_WNO_DEPRECATED_REGISTER_FLAG)
-check_cxx_compiler_flag(-Wsign-compare LIBOMP_HAVE_WSIGN_COMPARE_FLAG)
-check_cxx_compiler_flag(-msse2 LIBOMP_HAVE_MSSE2_FLAG)
-check_cxx_compiler_flag(-ftls-model=initial-exec LIBOMP_HAVE_FTLS_MODEL_FLAG)
+check_c_compiler_flag(-Werror LIBOMP_HAVE_WERROR_FLAG)
+check_c_compiler_flag(-Wunused-function LIBOMP_HAVE_WNO_UNUSED_FUNCTION_FLAG)
+check_c_compiler_flag(-Wunused-local-typedef LIBOMP_HAVE_WNO_UNUSED_LOCAL_TYPEDEF_FLAG)
+check_c_compiler_flag(-Wunused-value LIBOMP_HAVE_WNO_UNUSED_VALUE_FLAG)
+check_c_compiler_flag(-Wunused-variable LIBOMP_HAVE_WNO_UNUSED_VARIABLE_FLAG)
+check_c_compiler_flag(-Wswitch LIBOMP_HAVE_WNO_SWITCH_FLAG)
+check_c_compiler_flag(-Wcovered-switch-default LIBOMP_HAVE_WNO_COVERED_SWITCH_DEFAULT_FLAG)
+check_c_compiler_flag(-Wdeprecated-register LIBOMP_HAVE_WNO_DEPRECATED_REGISTER_FLAG)
+check_c_compiler_flag(-Wsign-compare LIBOMP_HAVE_WNO_SIGN_COMPARE_FLAG)
+check_c_compiler_flag(-Wgnu-anonymous-struct LIBOMP_HAVE_WNO_GNU_ANONYMOUS_STRUCT_FLAG)
+check_c_compiler_flag(-Wunknown-pragmas LIBOMP_HAVE_WNO_UNKNOWN_PRAGMAS_FLAG)
+check_c_compiler_flag(-Wmissing-field-initializers LIBOMP_HAVE_WNO_MISSING_FIELD_INITIALIZERS_FLAG)
+check_c_compiler_flag(-Wmissing-braces LIBOMP_HAVE_WNO_MISSING_BRACES_FLAG)
+check_c_compiler_flag(-Wcomment LIBOMP_HAVE_WNO_COMMENT_FLAG)
+check_c_compiler_flag(-Wself-assign LIBOMP_HAVE_WNO_SELF_ASSIGN_FLAG)
+check_c_compiler_flag(-Wvla-extension LIBOMP_HAVE_WNO_VLA_EXTENSION_FLAG)
+check_c_compiler_flag(-Wformat-pedantic LIBOMP_HAVE_WNO_FORMAT_PEDANTIC_FLAG)
+check_c_compiler_flag(-msse2 LIBOMP_HAVE_MSSE2_FLAG)
+check_c_compiler_flag(-ftls-model=initial-exec LIBOMP_HAVE_FTLS_MODEL_FLAG)
 libomp_check_architecture_flag(-mmic LIBOMP_HAVE_MMIC_FLAG)
 libomp_check_architecture_flag(-m32 LIBOMP_HAVE_M32_FLAG)
 if(WIN32)