LCC: Add dedicated support for MCST LCC compiler

Divert LCC compiler as a new one, instead of treating it as GNU.

Since old times, Elbrus C/C++/Fortran Compiler (LCC) by MCST has been
passing checks for GNU compilers, so it has been identified as GNU.
Now, with intent of seriously upstreaming its support, it has been
added as a separate LCC compiler, and its version displays not a
supported GCC version, but LCC version itself (e.g. LCC 1.25.19 instead
of GNU 7.3.0).

This commit adds its support for detection, and also converts basically
every check like 'is this compiler GNU?' to 'is this compiler GNU or
LCC?'. The only places where this check is untouched, is where it
regards other platforms where LCC is unavailable (primarily non-Linux),
and where it REALLY differs from GNU compiler.

Note: this transition may break software that are already ported to
Elbrus, but hardly relies that LCC will be detected as GNU; still such
software is not known.

30 files changed, 65 insertions, 55 deletions

diff --git a/Tests/Assembler/CMakeLists.txt b/Tests/Assembler/CMakeLists.txt
index 0a2c819..65207d8 100644
--- a/Tests/Assembler/CMakeLists.txt
+++ b/Tests/Assembler/CMakeLists.txt
@@ -9,7 +9,7 @@ set(SRCS)
 # and also generate assembler files from C:
 if("${CMAKE_GENERATOR}" MATCHES "Makefile|Xcode|Ninja" AND
     NOT CMAKE_OSX_ARCHITECTURES MATCHES ";")
-  if((CMAKE_C_COMPILER_ID MATCHES "^(GNU|Clang|AppleClang|HP|SunPro|XL)$") OR (CMAKE_C_COMPILER_ID MATCHES "Intel"  AND  UNIX)
+  if((CMAKE_C_COMPILER_ID MATCHES "^(GNU|LCC|Clang|AppleClang|HP|SunPro|XL)$") OR (CMAKE_C_COMPILER_ID MATCHES "Intel"  AND  UNIX)
      AND NOT (CMAKE_C_COMPILER_ID STREQUAL "Clang" AND "x${CMAKE_C_COMPILER_FRONTEND_VARIANT}" STREQUAL "xMSVC"))
     set(C_FLAGS "${CMAKE_C_FLAGS}")
     separate_arguments(C_FLAGS)
diff --git a/Tests/CMakeCommands/add_compile_options/CMakeLists.txt b/Tests/CMakeCommands/add_compile_options/CMakeLists.txt
index b28d0be..6e5160b 100644
--- a/Tests/CMakeCommands/add_compile_options/CMakeLists.txt
+++ b/Tests/CMakeCommands/add_compile_options/CMakeLists.txt
@@ -6,7 +6,7 @@ add_compile_options(-DTEST_OPTION)
 
 add_executable(add_compile_options main.cpp)
 
-if(CMAKE_CXX_COMPILER_ID MATCHES "GNU")
+if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|LCC")
   target_compile_definitions(add_compile_options
     PRIVATE
       "DO_GNU_TESTS"
diff --git a/Tests/CMakeCommands/target_compile_options/CMakeLists.txt b/Tests/CMakeCommands/target_compile_options/CMakeLists.txt
index 268c7eb..362133e 100644
--- a/Tests/CMakeCommands/target_compile_options/CMakeLists.txt
+++ b/Tests/CMakeCommands/target_compile_options/CMakeLists.txt
@@ -7,14 +7,14 @@ add_executable(target_compile_options
   "${CMAKE_CURRENT_SOURCE_DIR}/main.cpp"
 )
 target_compile_options(target_compile_options
-  PRIVATE $<$<CXX_COMPILER_ID:AppleClang,Clang,GNU>:-DMY_PRIVATE_DEFINE>
-  PUBLIC $<$<COMPILE_LANG_AND_ID:CXX,GNU>:-DMY_PUBLIC_DEFINE>
-  PUBLIC $<$<COMPILE_LANG_AND_ID:CXX,GNU,Clang,AppleClang>:-DMY_MUTLI_COMP_PUBLIC_DEFINE>
-  INTERFACE $<$<CXX_COMPILER_ID:GNU>:-DMY_INTERFACE_DEFINE>
-  INTERFACE $<$<CXX_COMPILER_ID:GNU,Clang,AppleClang>:-DMY_MULTI_COMP_INTERFACE_DEFINE>
+  PRIVATE $<$<CXX_COMPILER_ID:AppleClang,Clang,GNU,LCC>:-DMY_PRIVATE_DEFINE>
+  PUBLIC $<$<COMPILE_LANG_AND_ID:CXX,GNU,LCC>:-DMY_PUBLIC_DEFINE>
+  PUBLIC $<$<COMPILE_LANG_AND_ID:CXX,GNU,LCC,Clang,AppleClang>:-DMY_MUTLI_COMP_PUBLIC_DEFINE>
+  INTERFACE $<$<CXX_COMPILER_ID:GNU,LCC>:-DMY_INTERFACE_DEFINE>
+  INTERFACE $<$<CXX_COMPILER_ID:GNU,LCC,Clang,AppleClang>:-DMY_MULTI_COMP_INTERFACE_DEFINE>
 )
 
-if(CMAKE_CXX_COMPILER_ID MATCHES "GNU")
+if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|LCC")
   target_compile_definitions(target_compile_options
     PRIVATE
       "DO_GNU_TESTS"
@@ -47,10 +47,10 @@ if(CMAKE_GENERATOR MATCHES "Visual Studio")
 endif()
 
 target_compile_options(consumer
-  PRIVATE $<$<CXX_COMPILER_ID:GNU,Clang,AppleClang>:$<TARGET_PROPERTY:target_compile_options,INTERFACE_COMPILE_OPTIONS>>
+  PRIVATE $<$<CXX_COMPILER_ID:GNU,LCC,Clang,AppleClang>:$<TARGET_PROPERTY:target_compile_options,INTERFACE_COMPILE_OPTIONS>>
 )
 
-if(CMAKE_CXX_COMPILER_ID MATCHES "GNU")
+if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|LCC")
   target_compile_definitions(consumer
     PRIVATE
       "DO_GNU_TESTS"
diff --git a/Tests/CMakeCommands/target_link_libraries/cmp0022/CMakeLists.txt b/Tests/CMakeCommands/target_link_libraries/cmp0022/CMakeLists.txt
index 741c73e..83103cf 100644
--- a/Tests/CMakeCommands/target_link_libraries/cmp0022/CMakeLists.txt
+++ b/Tests/CMakeCommands/target_link_libraries/cmp0022/CMakeLists.txt
@@ -25,7 +25,7 @@ target_link_libraries(staticlib1 LINK_PUBLIC staticlib2)
 
 # Try adding a private link item to be propagated out of a static lib.
 set(private_link "")
-if (CMAKE_CXX_COMPILER_ID MATCHES GNU OR CMAKE_CXX_COMPILER_ID MATCHES Clang)
+if (CMAKE_CXX_COMPILER_ID MATCHES GNU OR CMAKE_CXX_COMPILER_ID MATCHES Clang OR CMAKE_CXX_COMPILER_ID MATCHES LCC)
   if (CMAKE_SYSTEM_NAME STREQUAL "SunOS")
     set(private_link "-Wl,-V")
   else()
diff --git a/Tests/CMakeLists.txt b/Tests/CMakeLists.txt
index d1f7b69..f3722bf 100644
--- a/Tests/CMakeLists.txt
+++ b/Tests/CMakeLists.txt
@@ -531,8 +531,8 @@ if(BUILD_TESTING)
   if (NOT CMAKE_GENERATOR STREQUAL "Xcode")
     ADD_TEST_MACRO(SourceFileIncludeDirProperty SourceFileIncludeDirProperty)
   endif()
-  if(CMAKE_CXX_COMPILER_ID STREQUAL GNU
-      AND NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.7)
+  if(CMAKE_CXX_COMPILER_ID STREQUAL "LCC" OR (CMAKE_CXX_COMPILER_ID STREQUAL "GNU"
+      AND NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.7))
     set(runCxxDialectTest 1)
   endif()
   if(CMAKE_CXX_COMPILER_ID STREQUAL Clang
@@ -670,7 +670,7 @@ if(BUILD_TESTING)
 
   ADD_TEST_MACRO(Module.WriteCompilerDetectionHeader WriteCompilerDetectionHeader)
 
-  if (APPLE OR CMAKE_CXX_COMPILER_ID MATCHES "GNU")
+  if (APPLE OR CMAKE_CXX_COMPILER_ID MATCHES "GNU" OR CMAKE_CXX_COMPILER_ID MATCHES "LCC")
     include(CheckCXXCompilerFlag)
     check_cxx_compiler_flag(-fPIE run_pic_test)
   else()
@@ -687,9 +687,10 @@ if(BUILD_TESTING)
     ADD_TEST_MACRO(PositionIndependentTargets PositionIndependentTargets)
   endif()
 
-  if((CMAKE_CXX_COMPILER_ID MATCHES "GNU") AND
+  if(CMAKE_CXX_COMPILER_ID MATCHES "LCC" OR
+    ((CMAKE_CXX_COMPILER_ID MATCHES "GNU") AND
     (NOT "${CMAKE_CXX_COMPILER_VERSION}" VERSION_LESS 4.2) AND
-    (CMAKE_SYSTEM_NAME MATCHES "Linux"))
+    (CMAKE_SYSTEM_NAME MATCHES "Linux")))
 
     include(CheckCXXCompilerFlag)
     check_cxx_compiler_flag(
@@ -2004,7 +2005,7 @@ if(BUILD_TESTING)
   set_tests_properties ( linkorder2 PROPERTIES DEPENDS linkorder1)
 
   # Test static linking on toolchains known to support it.
-  if(CMAKE_C_COMPILER_ID STREQUAL "GNU"
+  if((CMAKE_C_COMPILER_ID STREQUAL "GNU" OR CMAKE_C_COMPILER_ID STREQUAL "LCC")
       AND NOT APPLE AND NOT WIN32 AND NOT CYGWIN
       AND EXISTS "/usr/lib/libm.a")
     add_test(LinkStatic  ${CMAKE_CTEST_COMMAND}
@@ -3657,6 +3658,7 @@ if(BUILD_TESTING)
   if(CMAKE_GENERATOR MATCHES "^((Unix|MSYS) Makefiles|Ninja)$" AND
      ((CMAKE_CXX_COMPILER_ID STREQUAL "GNU" AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 4.4)
       OR (CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND NOT "x${CMAKE_CXX_SIMULATE_ID}" STREQUAL "xMSVC")
+      OR (CMAKE_CXX_COMPILER_ID STREQUAL "LCC")
       OR (CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang")))
     add_test(IncludeDirectoriesCPATH ${CMAKE_CTEST_COMMAND}
       --build-and-test
diff --git a/Tests/CMakeOnly/CheckCXXCompilerFlag/CMakeLists.txt b/Tests/CMakeOnly/CheckCXXCompilerFlag/CMakeLists.txt
index aca99ce..9c203c7 100644
--- a/Tests/CMakeOnly/CheckCXXCompilerFlag/CMakeLists.txt
+++ b/Tests/CMakeOnly/CheckCXXCompilerFlag/CMakeLists.txt
@@ -57,7 +57,7 @@ else()
   message("Unhandled Platform")
 endif()
 
-if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang" AND NOT "x${CMAKE_CXX_SIMULATE_ID}" STREQUAL "xMSVC")
+if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|LCC|Clang" AND NOT "x${CMAKE_CXX_SIMULATE_ID}" STREQUAL "xMSVC")
   check_cxx_compiler_flag("-x c++" HAVE_X_CXX)
   if(NOT HAVE_X_CXX)
     message(FATAL_ERROR "${CMAKE_CXX_COMPILER_ID} compiler flag '-x c++' check failed")
diff --git a/Tests/CompileFeatures/cxx_generalized_initializers.cpp b/Tests/CompileFeatures/cxx_generalized_initializers.cpp
index bfe0d41..c4f47fe 100644
--- a/Tests/CompileFeatures/cxx_generalized_initializers.cpp
+++ b/Tests/CompileFeatures/cxx_generalized_initializers.cpp
@@ -11,8 +11,11 @@ class initializer_list
   const _E* __begin_;
   size_t __size_;
 
-#ifdef __INTEL_COMPILER
-  // The Intel compiler internally asserts the constructor overloads, so
+#if defined(__INTEL_COMPILER) ||                                              \
+  (defined(__LCC__) &&                                                        \
+   (defined(__GNUC__) || defined(__GNUG__) || defined(__MCST__)))
+  // Compilers based on EDG, such as Intel compiler and MCST LCC,
+  // internally assert the constructor overloads, so
   // reproduce the constructor used in its <initializer_list> header.
   initializer_list(const _E*, size_t) {}
 #else
diff --git a/Tests/CompileOptions/CMakeLists.txt b/Tests/CompileOptions/CMakeLists.txt
index 1bedac0..e6db5b7 100644
--- a/Tests/CompileOptions/CMakeLists.txt
+++ b/Tests/CompileOptions/CMakeLists.txt
@@ -30,8 +30,8 @@ endif()
 set_property(TARGET CompileOptions PROPERTY COMPILE_OPTIONS
   "-DTEST_DEFINE"
   "-DNEEDS_ESCAPE=\"E$CAPE\""
-  "$<$<CXX_COMPILER_ID:GNU>:-DTEST_DEFINE_GNU>"
-  "$<$<COMPILE_LANG_AND_ID:CXX,GNU>:-DTEST_DEFINE_CXX_AND_GNU>"
+  "$<$<CXX_COMPILER_ID:GNU,LCC>:-DTEST_DEFINE_GNU>"
+  "$<$<COMPILE_LANG_AND_ID:CXX,GNU,LCC>:-DTEST_DEFINE_CXX_AND_GNU>"
   "SHELL:" # produces no options
   ${c_tests}
   ${cxx_tests}
@@ -49,15 +49,15 @@ else()
     )
 endif()
 
-if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang|Borland|Embarcadero" AND NOT "${CMAKE_GENERATOR}" MATCHES "NMake Makefiles")
+if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|LCC|Clang|Borland|Embarcadero" AND NOT "${CMAKE_GENERATOR}" MATCHES "NMake Makefiles")
   set_property(TARGET CompileOptions APPEND PROPERTY COMPILE_OPTIONS
     "-DTEST_OCTOTHORPE=\"#\""
     )
 endif()
 
-if(CMAKE_CXX_COMPILER_ID MATCHES "^(GNU|AppleClang|MSVC)$")
+if(CMAKE_CXX_COMPILER_ID MATCHES "^(GNU|LCC|AppleClang|MSVC)$")
   target_compile_definitions(CompileOptions PRIVATE "DO_FLAG_TESTS")
-  if(CMAKE_CXX_COMPILER_ID MATCHES "^(GNU|AppleClang)$")
+  if(CMAKE_CXX_COMPILER_ID MATCHES "^(GNU|LCC|AppleClang)$")
     string(APPEND CMAKE_CXX_FLAGS " -w")
   endif()
   string(APPEND CMAKE_CXX_FLAGS                " -DFLAG_A=1 -DFLAG_B=1")
@@ -79,7 +79,7 @@ endif()
 
 target_link_libraries(CompileOptions testlib)
 
-if(CMAKE_CXX_COMPILER_ID MATCHES "GNU")
+if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|LCC")
   target_compile_definitions(CompileOptions
     PRIVATE
       "DO_GNU_TESTS"
diff --git a/Tests/ExportImport/Export/CMakeLists.txt b/Tests/ExportImport/Export/CMakeLists.txt
index a2968d4..9453852 100644
--- a/Tests/ExportImport/Export/CMakeLists.txt
+++ b/Tests/ExportImport/Export/CMakeLists.txt
@@ -286,6 +286,7 @@ set_property(TARGET testSharedLibRequired
 set_property(TARGET testSharedLibRequired APPEND PROPERTY
   INTERFACE_COMPILE_OPTIONS
     $<$<CXX_COMPILER_ID:GNU>:-DCUSTOM_COMPILE_OPTION>
+    $<$<CXX_COMPILER_ID:LCC>:-DCUSTOM_COMPILE_OPTION>
 )
 
 add_library(testSharedLibRequiredUser SHARED testSharedLibRequiredUser.cpp)
diff --git a/Tests/ExportImport/Import/A/CMakeLists.txt b/Tests/ExportImport/Import/A/CMakeLists.txt
index 3cb3833..860a0bc 100644
--- a/Tests/ExportImport/Import/A/CMakeLists.txt
+++ b/Tests/ExportImport/Import/A/CMakeLists.txt
@@ -325,14 +325,14 @@ target_compile_definitions(deps_shared_iface
     $<$<STREQUAL:$<TARGET_PROPERTY:CUSTOM_STRING>,testcontent>:CUSTOM_STRING_IS_MATCH>
 )
 
-if(CMAKE_CXX_COMPILER_ID MATCHES "GNU")
+if(CMAKE_CXX_COMPILER_ID MATCHES "GNU" OR CMAKE_CXX_COMPILER_ID MATCHES "LCC")
   target_compile_definitions(deps_shared_iface
     PRIVATE
       "DO_GNU_TESTS"
   )
 endif()
 
-if (APPLE OR CMAKE_CXX_COMPILER_ID MATCHES "GNU")
+if (APPLE OR CMAKE_CXX_COMPILER_ID MATCHES "GNU" OR CMAKE_CXX_COMPILER_ID MATCHES "LCC")
   include(CheckCXXCompilerFlag)
   check_cxx_compiler_flag(-fPIE run_pic_test)
 else()
@@ -365,7 +365,7 @@ endif()
 
 add_executable(deps_shared_iface2 deps_shared_iface.cpp)
 target_link_libraries(deps_shared_iface2 bld_testSharedLibDepends bld_subdirlib)
-if(CMAKE_CXX_COMPILER_ID MATCHES "GNU")
+if(CMAKE_CXX_COMPILER_ID MATCHES "GNU" OR CMAKE_CXX_COMPILER_ID MATCHES "LCC")
   target_compile_definitions(deps_shared_iface2
     PRIVATE
       "DO_GNU_TESTS"
@@ -413,6 +413,7 @@ endforeach()
 unset(_configs)
 
 if (((CMAKE_C_COMPILER_ID STREQUAL GNU AND CMAKE_C_COMPILER_VERSION VERSION_GREATER 4.4)
+    OR CMAKE_C_COMPILER_ID MATCHES "LCC"
     OR (CMAKE_C_COMPILER_ID STREQUAL Clang AND NOT "x${CMAKE_CXX_SIMULATE_ID}" STREQUAL "xMSVC"))
     AND (CMAKE_GENERATOR STREQUAL "Unix Makefiles" OR CMAKE_GENERATOR STREQUAL "Ninja"))
   include(CheckCXXCompilerFlag)
diff --git a/Tests/Fortran/CMakeLists.txt b/Tests/Fortran/CMakeLists.txt
index 2fc47a5..69899e9 100644
--- a/Tests/Fortran/CMakeLists.txt
+++ b/Tests/Fortran/CMakeLists.txt
@@ -14,7 +14,7 @@ if(CMAKE_Fortran_COMPILER_ID MATCHES "^(XL|VisualAge)$")
   # We do not implement SHARED Fortran libs on AIX yet!
   # Workaround: Set LINKER_LANGUAGE to C, which uses 'xlc' and Fortran implicits.
   set(_SHARED STATIC)
-elseif(CMAKE_Fortran_COMPILER_ID STREQUAL "GNU")
+elseif(CMAKE_Fortran_COMPILER_ID MATCHES "GNU|LCC")
   # g77 2.96 does not support shared libs on Itanium because g2c is not -fPIC
   execute_process(COMMAND ${CMAKE_Fortran_COMPILER} --version
                   OUTPUT_VARIABLE output ERROR_VARIABLE output)
@@ -26,7 +26,7 @@ endif()
 # Pick a module .def file with the properly mangled symbol name.
 set(world_def "")
 if(WIN32 AND NOT CYGWIN)
-  if(CMAKE_Fortran_COMPILER_ID MATCHES "GNU")
+  if(CMAKE_Fortran_COMPILER_ID MATCHES "GNU|LCC")
     set(world_def world_gnu.def)
   elseif(CMAKE_Fortran_COMPILER_ID MATCHES "Intel" OR
       CMAKE_GENERATOR MATCHES "Visual Studio") # Intel plugin
diff --git a/Tests/IncludeDirectories/CMakeLists.txt b/Tests/IncludeDirectories/CMakeLists.txt
index 4c488e6..c48df5a 100644
--- a/Tests/IncludeDirectories/CMakeLists.txt
+++ b/Tests/IncludeDirectories/CMakeLists.txt
@@ -4,6 +4,7 @@ project(IncludeDirectories)
 if (((CMAKE_C_COMPILER_ID STREQUAL GNU AND CMAKE_C_COMPILER_VERSION VERSION_GREATER 4.4)
     OR (CMAKE_C_COMPILER_ID STREQUAL Clang AND NOT "x${CMAKE_CXX_SIMULATE_ID}" STREQUAL "xMSVC")
     OR CMAKE_C_COMPILER_ID STREQUAL AppleClang
+    OR CMAKE_C_COMPILER_ID STREQUAL LCC
     OR ("x${CMAKE_C_COMPILER_ID}" STREQUAL "xMSVC" AND
        CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL "19.29.30036.3" AND
        NOT CMAKE_GENERATOR MATCHES "Visual Studio")) # No support for VS generators yet.
diff --git a/Tests/LinkStatic/CMakeLists.txt b/Tests/LinkStatic/CMakeLists.txt
index 200d4e5..60a270b 100644
--- a/Tests/LinkStatic/CMakeLists.txt
+++ b/Tests/LinkStatic/CMakeLists.txt
@@ -1,8 +1,8 @@
 cmake_minimum_required(VERSION 2.8.4.20110303 FATAL_ERROR)
 project(LinkStatic C)
 
-if(NOT CMAKE_C_COMPILER_ID STREQUAL "GNU")
-  message(FATAL_ERROR "This test works only with the GNU compiler!")
+if(NOT CMAKE_C_COMPILER_ID MATCHES "GNU|LCC")
+  message(FATAL_ERROR "This test works only with the GNU or LCC compiler!")
 endif()
 
 find_library(MATH_LIBRARY NAMES libm.a)
diff --git a/Tests/Module/WriteCompilerDetectionHeader/CMakeLists.txt b/Tests/Module/WriteCompilerDetectionHeader/CMakeLists.txt
index e406758..694073a 100644
--- a/Tests/Module/WriteCompilerDetectionHeader/CMakeLists.txt
+++ b/Tests/Module/WriteCompilerDetectionHeader/CMakeLists.txt
@@ -52,7 +52,7 @@ endmacro()
 # detailed features tables, not just meta-features
 
 if (CMAKE_C_COMPILE_FEATURES)
-  if (NOT CMAKE_C_COMPILER_ID MATCHES "^(Cray|PGI|NVHPC|XL|XLClang|IntelLLVM|Fujitsu|FujitsuClang)$")
+  if (NOT CMAKE_C_COMPILER_ID MATCHES "^(LCC|Cray|PGI|NVHPC|XL|XLClang|IntelLLVM|Fujitsu|FujitsuClang)$")
     set(C_expected_features ${CMAKE_C_COMPILE_FEATURES})
     list(FILTER C_expected_features EXCLUDE REGEX "^c_std_[0-9][0-9]")
   endif()
@@ -95,7 +95,7 @@ if (C_expected_features)
 endif()
 
 if (CMAKE_CXX_COMPILE_FEATURES)
-  if (NOT CMAKE_CXX_COMPILER_ID MATCHES "^(Cray|PGI|NVHPC|XL|XLClang|IntelLLVM|Fujitsu|FujitsuClang)$")
+  if (NOT CMAKE_CXX_COMPILER_ID MATCHES "^(LCC|Cray|PGI|NVHPC|XL|XLClang|IntelLLVM|Fujitsu|FujitsuClang)$")
     set(CXX_expected_features ${CMAKE_CXX_COMPILE_FEATURES})
     list(FILTER CXX_expected_features EXCLUDE REGEX "^cxx_std_[0-9][0-9]")
   endif()
diff --git a/Tests/RunCMake/BuildDepends/RunCMakeTest.cmake b/Tests/RunCMake/BuildDepends/RunCMakeTest.cmake
index 27bbff6..06f416b 100644
--- a/Tests/RunCMake/BuildDepends/RunCMakeTest.cmake
+++ b/Tests/RunCMake/BuildDepends/RunCMakeTest.cmake
@@ -159,6 +159,7 @@ endif()
 
 if ((RunCMake_GENERATOR STREQUAL "Unix Makefiles"
       AND (CMAKE_C_COMPILER_ID STREQUAL "GNU"
+        OR CMAKE_C_COMPILER_ID STREQUAL "LCC"
         OR CMAKE_C_COMPILER_ID STREQUAL "Clang"
         OR CMAKE_C_COMPILER_ID STREQUAL "AppleClang"))
     OR (RunCMake_GENERATOR STREQUAL "NMake Makefiles"
diff --git a/Tests/RunCMake/CMP0119/RunCMakeTest.cmake b/Tests/RunCMake/CMP0119/RunCMakeTest.cmake
index e547ef5..7395827 100644
--- a/Tests/RunCMake/CMP0119/RunCMakeTest.cmake
+++ b/Tests/RunCMake/CMP0119/RunCMakeTest.cmake
@@ -12,6 +12,6 @@ if(NOT RunCMake_GENERATOR MATCHES "Visual Studio|Xcode" AND
   run_CMP0119(WARN)
   run_CMP0119(OLD)
 endif()
-if((CMAKE_C_COMPILER_ID MATCHES "(GNU|Clang|MSVC|Borland|Embarcadero|Intel|TI)"))
+if((CMAKE_C_COMPILER_ID MATCHES "(GNU|LCC|Clang|MSVC|Borland|Embarcadero|Intel|TI)"))
   run_CMP0119(NEW)
 endif()
diff --git a/Tests/RunCMake/CMakeLists.txt b/Tests/RunCMake/CMakeLists.txt
index e24ef58..c87c1b6 100644
--- a/Tests/RunCMake/CMakeLists.txt
+++ b/Tests/RunCMake/CMakeLists.txt
@@ -256,7 +256,7 @@ endif()
 add_RunCMake_test(ArtifactOutputDirs)
 
 if(NOT DEFINED CMake_TEST_BuildDepends_GNU_AS
-    AND CMAKE_C_COMPILER_ID STREQUAL "GNU"
+    AND (CMAKE_C_COMPILER_ID STREQUAL "GNU" OR CMAKE_C_COMPILER_ID STREQUAL "LCC")
     AND CMAKE_GENERATOR MATCHES "^Ninja"
     )
   execute_process(COMMAND "${CMAKE_C_COMPILER}" -print-prog-name=as
@@ -682,7 +682,7 @@ set_property(TEST RunCMake.CheckCompilerFlag
 add_RunCMake_test(CheckModules)
 add_RunCMake_test(CheckIPOSupported)
 if (CMAKE_SYSTEM_NAME MATCHES "(Linux|Darwin)"
-    AND (CMAKE_C_COMPILER_ID MATCHES "Clang|GNU" OR CMAKE_Fortran_COMPILER_ID MATCHES "GNU"))
+    AND (CMAKE_C_COMPILER_ID MATCHES "Clang|GNU|LCC" OR CMAKE_Fortran_COMPILER_ID MATCHES "GNU|LCC"))
   add_RunCMake_test(CheckLinkerFlag -DCMAKE_C_COMPILER_ID=${CMAKE_C_COMPILER_ID}
                                     -DCMAKE_Fortran_COMPILER_ID=${CMAKE_Fortran_COMPILER_ID}
                                     -DCMake_TEST_CUDA=${CMake_TEST_CUDA}
diff --git a/Tests/RunCMake/CPack/tests/DEBUGINFO/test.cmake b/Tests/RunCMake/CPack/tests/DEBUGINFO/test.cmake
index e9cebbf..1d21dec 100644
--- a/Tests/RunCMake/CPack/tests/DEBUGINFO/test.cmake
+++ b/Tests/RunCMake/CPack/tests/DEBUGINFO/test.cmake
@@ -1,7 +1,7 @@
 set(CMAKE_BUILD_WITH_INSTALL_RPATH 1)
 
 # Some compilers do not add build id to binaries by default.
-if(CMAKE_CXX_COMPILER_ID MATCHES "^(IntelLLVM|PGI|NVHPC)$")
+if(CMAKE_CXX_COMPILER_ID MATCHES "^(LCC|IntelLLVM|PGI|NVHPC)$")
   string(APPEND CMAKE_EXE_LINKER_FLAGS "-Wl,--build-id")
   string(APPEND CMAKE_SHARED_LINKER_FLAGS "-Wl,--build-id")
 endif()
diff --git a/Tests/RunCMake/CheckCompilerFlag/CheckCCompilerFlag.cmake b/Tests/RunCMake/CheckCompilerFlag/CheckCCompilerFlag.cmake
index 6483f11..79d67e5 100644
--- a/Tests/RunCMake/CheckCompilerFlag/CheckCCompilerFlag.cmake
+++ b/Tests/RunCMake/CheckCompilerFlag/CheckCCompilerFlag.cmake
@@ -9,14 +9,14 @@ if(SHOULD_FAIL)
   message(SEND_ERROR "invalid C compile flag didn't fail.")
 endif()
 
-if(CMAKE_C_COMPILER_ID MATCHES "GNU|Clang" AND NOT "x${CMAKE_C_SIMULATE_ID}" STREQUAL "xMSVC")
+if(CMAKE_C_COMPILER_ID MATCHES "GNU|LCC|Clang" AND NOT "x${CMAKE_C_SIMULATE_ID}" STREQUAL "xMSVC")
   check_compiler_flag(C "-x c" SHOULD_WORK)
   if(NOT SHOULD_WORK)
     message(SEND_ERROR "${CMAKE_C_COMPILER_ID} compiler flag '-x c' check failed")
   endif()
 endif()
 
-if(CMAKE_C_COMPILER_ID STREQUAL "GNU")
+if(CMAKE_C_COMPILER_ID STREQUAL "GNU") # LCC C compiler silently ignore -frtti instead of failing, so skip it here.
   check_compiler_flag(C "-frtti" SHOULD_FAIL_RTTI)
   if(SHOULD_FAIL_RTTI)
     message(SEND_ERROR "${CMAKE_C_COMPILER_ID} compiler flag '-frtti' check passed but should have failed")
diff --git a/Tests/RunCMake/CheckCompilerFlag/CheckCXXCompilerFlag.cmake b/Tests/RunCMake/CheckCompilerFlag/CheckCXXCompilerFlag.cmake
index 60e9755..4b20ebd 100644
--- a/Tests/RunCMake/CheckCompilerFlag/CheckCXXCompilerFlag.cmake
+++ b/Tests/RunCMake/CheckCompilerFlag/CheckCXXCompilerFlag.cmake
@@ -9,7 +9,7 @@ if(SHOULD_FAIL)
   message(SEND_ERROR "invalid CXX compile flag didn't fail.")
 endif()
 
-if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang" AND NOT "x${CMAKE_CXX_SIMULATE_ID}" STREQUAL "xMSVC")
+if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|LCC|Clang" AND NOT "x${CMAKE_CXX_SIMULATE_ID}" STREQUAL "xMSVC")
   check_compiler_flag(CXX "-x c++" SHOULD_WORK)
   if(NOT SHOULD_WORK)
     message(SEND_ERROR "${CMAKE_CXX_COMPILER_ID} compiler flag '-x c++' check failed")
diff --git a/Tests/RunCMake/CheckCompilerFlag/CheckFortranCompilerFlag.cmake b/Tests/RunCMake/CheckCompilerFlag/CheckFortranCompilerFlag.cmake
index 7bb88b1..236f37b 100644
--- a/Tests/RunCMake/CheckCompilerFlag/CheckFortranCompilerFlag.cmake
+++ b/Tests/RunCMake/CheckCompilerFlag/CheckFortranCompilerFlag.cmake
@@ -8,7 +8,7 @@ if(SHOULD_FAIL)
   message(SEND_ERROR "invalid Fortran compile flag didn't fail.")
 endif()
 
-if(CMAKE_Fortran_COMPILER_ID STREQUAL "GNU")
+if(CMAKE_Fortran_COMPILER_ID STREQUAL "GNU|LCC")
   check_compiler_flag(Fortran "-Wall" SHOULD_WORK)
   if(NOT SHOULD_WORK)
     message(SEND_ERROR "${CMAKE_Fortran_COMPILER_ID} compiler flag '-Wall' check failed")
diff --git a/Tests/RunCMake/CheckLinkerFlag/RunCMakeTest.cmake b/Tests/RunCMake/CheckLinkerFlag/RunCMakeTest.cmake
index 5e5bff6..39fc430 100644
--- a/Tests/RunCMake/CheckLinkerFlag/RunCMakeTest.cmake
+++ b/Tests/RunCMake/CheckLinkerFlag/RunCMakeTest.cmake
@@ -1,6 +1,6 @@
 include(RunCMake)
 
-if (CMAKE_C_COMPILER_ID MATCHES "Clang|GNU")
+if (CMAKE_C_COMPILER_ID MATCHES "Clang|GNU|LCC")
   run_cmake(CheckCLinkerFlag)
   run_cmake(CheckCXXLinkerFlag)
   if (APPLE)
@@ -9,7 +9,7 @@ if (CMAKE_C_COMPILER_ID MATCHES "Clang|GNU")
   endif()
 endif()
 
-if (CMAKE_Fortran_COMPILER_ID MATCHES "GNU")
+if (CMAKE_Fortran_COMPILER_ID MATCHES "GNU|LCC")
   run_cmake(CheckFortranLinkerFlag)
 endif()
 
diff --git a/Tests/RunCMake/FileAPI/codemodel-v2-check.py b/Tests/RunCMake/FileAPI/codemodel-v2-check.py
index 6cf57a3..92a64f9 100644
--- a/Tests/RunCMake/FileAPI/codemodel-v2-check.py
+++ b/Tests/RunCMake/FileAPI/codemodel-v2-check.py
@@ -731,7 +731,7 @@ def gen_check_targets(c, g, inSource):
         read_codemodel_json_data("targets/generated_exe.json"),
     ]
 
-    if cxx_compiler_id in ['Clang', 'AppleClang', 'GNU', 'Intel', 'IntelLLVM', 'MSVC', 'Embarcadero'] and g["name"] != "Xcode":
+    if cxx_compiler_id in ['Clang', 'AppleClang', 'LCC', 'GNU', 'Intel', 'IntelLLVM', 'MSVC', 'Embarcadero'] and g["name"] != "Xcode":
         for e in expected:
             if e["name"] == "cxx_exe":
                 if matches(g["name"], "^(Visual Studio |Ninja Multi-Config)"):
diff --git a/Tests/RunCMake/PositionIndependentCode/RunCMakeTest.cmake b/Tests/RunCMake/PositionIndependentCode/RunCMakeTest.cmake
index 6efa0d4..468b80a 100644
--- a/Tests/RunCMake/PositionIndependentCode/RunCMakeTest.cmake
+++ b/Tests/RunCMake/PositionIndependentCode/RunCMakeTest.cmake
@@ -26,6 +26,7 @@ if (PIE_SUPPORTED OR NO_PIE_SUPPORTED)
 
   if ((READELF OR OTOOL) AND
       (CMAKE_CXX_COMPILER_ID STREQUAL "GNU"
+        OR CMAKE_CXX_COMPILER_ID STREQUAL "LCC"
         OR CMAKE_CXX_COMPILER_ID STREQUAL "Clang"
         OR CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang"))
     macro(run_cmake_target test subtest)
diff --git a/Tests/RunCMake/PrecompileHeaders/PchWarnInvalid-check.cmake b/Tests/RunCMake/PrecompileHeaders/PchWarnInvalid-check.cmake
index 3e7fb30..ac3bf59 100644
--- a/Tests/RunCMake/PrecompileHeaders/PchWarnInvalid-check.cmake
+++ b/Tests/RunCMake/PrecompileHeaders/PchWarnInvalid-check.cmake
@@ -1,4 +1,4 @@
-if (NOT CMAKE_C_COMPILER_ID MATCHES "GNU|Intel" OR
+if (NOT CMAKE_C_COMPILER_ID MATCHES "GNU|LCC|Intel" OR
    (CMAKE_C_COMPILER_ID STREQUAL "Intel" AND CMAKE_HOST_WIN32))
   return()
 endif()
diff --git a/Tests/RunCMake/target_compile_options/RunCMakeTest.cmake b/Tests/RunCMake/target_compile_options/RunCMakeTest.cmake
index 806ae79..f726759 100644
--- a/Tests/RunCMake/target_compile_options/RunCMakeTest.cmake
+++ b/Tests/RunCMake/target_compile_options/RunCMakeTest.cmake
@@ -2,7 +2,7 @@ include(RunCMake)
 
 run_cmake(empty_keyword_args)
 
-if (CMAKE_C_COMPILER_ID MATCHES "GNU|Clang")
+if (CMAKE_C_COMPILER_ID MATCHES "GNU|LCC|Clang")
   macro(run_cmake_target test subtest target)
     set(RunCMake_TEST_BINARY_DIR ${RunCMake_BINARY_DIR}/${test}-build)
     set(RunCMake_TEST_OUTPUT_MERGE 1)
@@ -28,7 +28,7 @@ function(run_Order)
   run_cmake_command(Order-build ${CMAKE_COMMAND} --build . --verbose --config Custom)
 endfunction()
 if(RunCMake_GENERATOR MATCHES "Ninja|Make" AND
-    CMAKE_C_COMPILER_ID MATCHES "^(GNU|Clang|AppleClang)$" AND
+    CMAKE_C_COMPILER_ID MATCHES "^(GNU|LCC|Clang|AppleClang)$" AND
     NOT CMAKE_C_SIMULATE_ID STREQUAL "MSVC")
   run_Order()
 endif()
diff --git a/Tests/RunCMake/try_compile/RunCMakeTest.cmake b/Tests/RunCMake/try_compile/RunCMakeTest.cmake
index fffb038..28a990d 100644
--- a/Tests/RunCMake/try_compile/RunCMakeTest.cmake
+++ b/Tests/RunCMake/try_compile/RunCMakeTest.cmake
@@ -26,7 +26,7 @@ run_cmake(TargetTypeInvalid)
 run_cmake(TargetTypeStatic)
 
 if (CMAKE_SYSTEM_NAME MATCHES "^(Linux|Darwin|Windows)$" AND
-    CMAKE_C_COMPILER_ID MATCHES "^(MSVC|GNU|Clang|AppleClang)$")
+    CMAKE_C_COMPILER_ID MATCHES "^(MSVC|GNU|LCC|Clang|AppleClang)$")
   set (RunCMake_TEST_OPTIONS -DRunCMake_C_COMPILER_ID=${CMAKE_C_COMPILER_ID})
   run_cmake(LinkOptions)
   unset (RunCMake_TEST_OPTIONS)
@@ -60,10 +60,10 @@ if(CMake_TEST_ISPC)
   endif()
   run_cmake(ISPCDuplicateTarget${ninja})
 endif()
-if(CMAKE_C_COMPILER_ID STREQUAL "GNU" AND NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 4.4)
+if(CMAKE_C_COMPILER_ID MATCHES "GNU|LCC" AND NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 4.4)
   run_cmake(CStandardGNU)
 endif()
-if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU" AND NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.4)
+if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|LCC" AND NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.4)
   run_cmake(CxxStandardGNU)
 endif()
 
diff --git a/Tests/RunCMake/try_run/RunCMakeTest.cmake b/Tests/RunCMake/try_run/RunCMakeTest.cmake
index fa30eb4..d74add0 100644
--- a/Tests/RunCMake/try_run/RunCMakeTest.cmake
+++ b/Tests/RunCMake/try_run/RunCMakeTest.cmake
@@ -3,7 +3,7 @@ include(RunCMake)
 run_cmake(BadLinkLibraries)
 
 if (CMAKE_SYSTEM_NAME MATCHES "^(Linux|Darwin|Windows)$" AND
-    CMAKE_C_COMPILER_ID MATCHES "^(MSVC|GNU|Clang|AppleClang)$")
+    CMAKE_C_COMPILER_ID MATCHES "^(MSVC|GNU|LCC|Clang|AppleClang)$")
   set (RunCMake_TEST_OPTIONS -DRunCMake_C_COMPILER_ID=${CMAKE_C_COMPILER_ID})
   run_cmake(LinkOptions)
   unset (RunCMake_TEST_OPTIONS)
diff --git a/Tests/SetLang/CMakeLists.txt b/Tests/SetLang/CMakeLists.txt
index 80348ab..5b2eb19 100644
--- a/Tests/SetLang/CMakeLists.txt
+++ b/Tests/SetLang/CMakeLists.txt
@@ -20,7 +20,7 @@ if(CMAKE_GENERATOR MATCHES "^Visual Studio" AND "x${CMAKE_C_COMPILER_ID}" STREQU
   set_property(TARGET stay PROPERTY COMPILE_OPTIONS "-TP")
 endif()
 
-if((CMAKE_C_COMPILER_ID MATCHES "(GNU|Clang|MSVC|Borland|Embarcadero|Intel|TI|XL)"))
+if((CMAKE_C_COMPILER_ID MATCHES "(GNU|LCC|Clang|MSVC|Borland|Embarcadero|Intel|TI|XL)"))
   cmake_policy(SET CMP0119 NEW)
   add_library(zoom zoom.zzz)
   set_source_files_properties(zoom.zzz PROPERTIES LANGUAGE CXX)
diff --git a/Tests/TryCompile/CMakeLists.txt b/Tests/TryCompile/CMakeLists.txt
index d0c413f..e35e0d3 100644
--- a/Tests/TryCompile/CMakeLists.txt
+++ b/Tests/TryCompile/CMakeLists.txt
@@ -321,7 +321,7 @@ if(DEFINED CXX_BOGUS_FLAG)
   message(SEND_ERROR "CHECK_CXX_COMPILER_FLAG shouldn't construct CXX_BOGUS_FLAG as a normal variable")
 endif()
 
-if(CMAKE_C_COMPILER_ID STREQUAL "GNU")
+if(CMAKE_C_COMPILER_ID STREQUAL "GNU" OR CMAKE_C_COMPILER_ID STREQUAL "LCC")
   unset(C_STRICT_PROTOTYPES CACHE)
   CHECK_C_COMPILER_FLAG("-Werror;-Wstrict-prototypes" C_STRICT_PROTOTYPES)
   TEST_ASSERT(C_STRICT_PROTOTYPES "CHECK_C_COMPILER_FLAG failed -Werror -Wstrict-prototypes")