3 files changed, 16 insertions, 0 deletions
diff --git a/Modules/Compiler/Clang-CXX.cmake b/Modules/Compiler/Clang-CXX.cmake
index 6fb0200..c116078 100644
--- a/Modules/Compiler/Clang-CXX.cmake
+++ b/Modules/Compiler/Clang-CXX.cmake
@@ -29,9 +29,11 @@ if(NOT "x${CMAKE_CXX_SIMULATE_ID}" STREQUAL "xMSVC")
   if(NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 3.5)
     set(CMAKE_CXX14_STANDARD_COMPILE_OPTION "-std=c++14")
     set(CMAKE_CXX14_EXTENSION_COMPILE_OPTION "-std=gnu++14")
+    set(CMAKE_CXX14_STANDARD__HAS_FULL_SUPPORT ON)
   elseif(NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 3.4)
     set(CMAKE_CXX14_STANDARD_COMPILE_OPTION "-std=c++1y")
     set(CMAKE_CXX14_EXTENSION_COMPILE_OPTION "-std=gnu++1y")
+    set(CMAKE_CXX14_STANDARD__HAS_FULL_SUPPORT ON)
   endif()
 
   set(_clang_version_std17 5.0)
diff --git a/Modules/Compiler/GNU-CXX.cmake b/Modules/Compiler/GNU-CXX.cmake
index 1253291..fcaaeab 100644
--- a/Modules/Compiler/GNU-CXX.cmake
+++ b/Modules/Compiler/GNU-CXX.cmake
@@ -38,6 +38,10 @@ elseif (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.8)
   set(CMAKE_CXX14_EXTENSION_COMPILE_OPTION "-std=gnu++1y")
 endif()
 
+if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.0)
+  set(CMAKE_CXX14_STANDARD__HAS_FULL_SUPPORT ON)
+endif()
+
 if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 8.0)
   set(CMAKE_CXX17_STANDARD_COMPILE_OPTION "-std=c++17")
   set(CMAKE_CXX17_EXTENSION_COMPILE_OPTION "-std=gnu++17")
diff --git a/Modules/Compiler/Intel-CXX.cmake b/Modules/Compiler/Intel-CXX.cmake
index 032071c..44b0c3d 100644
--- a/Modules/Compiler/Intel-CXX.cmake
+++ b/Modules/Compiler/Intel-CXX.cmake
@@ -40,6 +40,16 @@ else()
     set(CMAKE_CXX17_EXTENSION_COMPILE_OPTION "-std=gnu++17")
   endif()
 
+  # While full C++14 support was first introduced in Intel 17,
+  # Intel 18.0.0-4 don't have full support as they broke
+  # support for cxx_relaxed_constexpr.
+  if (CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 18.0.4)
+    set(CMAKE_CXX14_STANDARD__HAS_FULL_SUPPORT ON)
+  elseif(CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 17.0.0
+        AND CMAKE_CXX_COMPILER_VERSION VERSION_LESS 18.0.0)
+    set(CMAKE_CXX14_STANDARD__HAS_FULL_SUPPORT ON)
+  endif()
+
   if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 15.0.2)
     set(CMAKE_CXX14_STANDARD_COMPILE_OPTION "-std=c++14")
   elseif (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 15.0.0)