Merge topic 'intel-llvm-compilers'

9b5fd04905 Tests: Disable MFC test for IntelLLVM due to #18311
ccdf7c0005 Tests: Skip VSGNUFortran test for ifx.
ddaf412dd0 Tests: Skip per file PDBs in PDBDirectoryAndName for IntelLLVM
a619b32768 Tests: Update RunCMake.GenerateExportHeader for IntelLLVM
661b04d6a6 Tests: Skip old PrecompiledHeader test on IntelLLVM
01b1e9c40d Tests: Update CompileFeatures test for IntelLLVM
f26f10184f Tests: Update Module.WriteCompilerDetectionHeader for IntelLLVM
3ceb364b1c Tests: Update RunCMake.FileAPI for IntelLLVM
...

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !5594

66 files changed, 613 insertions, 74 deletions

diff --git a/Help/variable/CMAKE_LANG_COMPILER_ID.rst b/Help/variable/CMAKE_LANG_COMPILER_ID.rst
index 1270610..89d9e27 100644
--- a/Help/variable/CMAKE_LANG_COMPILER_ID.rst
+++ b/Help/variable/CMAKE_LANG_COMPILER_ID.rst
@@ -25,6 +25,7 @@ include:
   HP = Hewlett-Packard Compiler (hp.com)
   IAR = IAR Systems (iar.com)
   Intel = Intel Compiler (intel.com)
+  IntelLLVM = Intel LLVM-Based Compiler (intel.com)
   MSVC = Microsoft Visual Studio (microsoft.com)
   NVHPC = NVIDIA HPC SDK Compiler (nvidia.com)
   NVIDIA = NVIDIA CUDA Compiler (nvidia.com)
diff --git a/Modules/CMakeCompilerIdDetection.cmake b/Modules/CMakeCompilerIdDetection.cmake
index d64804e..214d58a 100644
--- a/Modules/CMakeCompilerIdDetection.cmake
+++ b/Modules/CMakeCompilerIdDetection.cmake
@@ -49,6 +49,7 @@ function(compiler_id_detection outvar lang)
     endif()
     list(APPEND ordered_compilers
       Intel
+      IntelLLVM
       PathScale
       Embarcadero
       Borland
diff --git a/Modules/CMakeDetermineASMCompiler.cmake b/Modules/CMakeDetermineASMCompiler.cmake
index a3e5a12..e8b9db7 100644
--- a/Modules/CMakeDetermineASMCompiler.cmake
+++ b/Modules/CMakeDetermineASMCompiler.cmake
@@ -78,6 +78,10 @@ if(NOT CMAKE_ASM${ASM_DIALECT}_COMPILER_ID)
   set(CMAKE_ASM${ASM_DIALECT}_COMPILER_ID_VENDOR_FLAGS_Intel "--version")
   set(CMAKE_ASM${ASM_DIALECT}_COMPILER_ID_VENDOR_REGEX_Intel "(ICC)")
 
+  list(APPEND CMAKE_ASM${ASM_DIALECT}_COMPILER_ID_VENDORS IntelLLVM )
+  set(CMAKE_ASM${ASM_DIALECT}_COMPILER_ID_VENDOR_FLAGS_IntelLLVM "--version")
+  set(CMAKE_ASM${ASM_DIALECT}_COMPILER_ID_VENDOR_REGEX_IntelLLVM "(Intel[^\n]+oneAPI)")
+
   list(APPEND CMAKE_ASM${ASM_DIALECT}_COMPILER_ID_VENDORS SunPro )
   set(CMAKE_ASM${ASM_DIALECT}_COMPILER_ID_VENDOR_FLAGS_SunPro "-V")
   set(CMAKE_ASM${ASM_DIALECT}_COMPILER_ID_VENDOR_REGEX_SunPro "Sun C")
diff --git a/Modules/CMakeDetermineCCompiler.cmake b/Modules/CMakeDetermineCCompiler.cmake
index ab33b40..59c0574 100644
--- a/Modules/CMakeDetermineCCompiler.cmake
+++ b/Modules/CMakeDetermineCCompiler.cmake
@@ -59,7 +59,7 @@ else()
 
     # finally list compilers to try
     if(NOT CMAKE_C_COMPILER_INIT)
-      set(CMAKE_C_COMPILER_LIST ${_CMAKE_TOOLCHAIN_PREFIX}cc ${_CMAKE_TOOLCHAIN_PREFIX}gcc cl bcc xlc clang)
+      set(CMAKE_C_COMPILER_LIST ${_CMAKE_TOOLCHAIN_PREFIX}cc ${_CMAKE_TOOLCHAIN_PREFIX}gcc cl bcc xlc icx clang)
     endif()
 
     _cmake_find_compiler(C)
@@ -134,7 +134,8 @@ else()
     # variable but are not aware of CMAKE_C_COMPILER_FRONTEND_VARIANT.
     # They pre-date our support for the GNU-like variant targeting the
     # MSVC ABI so we do not consider that here.
-    if(CMAKE_C_COMPILER_ID STREQUAL "Clang")
+    if(CMAKE_C_COMPILER_ID STREQUAL "Clang"
+      OR "x${CMAKE_${lang}_COMPILER_ID" STREQUAL "xIntelLLVM")
       if("x${CMAKE_C_SIMULATE_ID}" STREQUAL "xMSVC")
         set(CMAKE_C_COMPILER_FRONTEND_VARIANT "MSVC")
       else()
diff --git a/Modules/CMakeDetermineCXXCompiler.cmake b/Modules/CMakeDetermineCXXCompiler.cmake
index 7283bc2..fd07a5c 100644
--- a/Modules/CMakeDetermineCXXCompiler.cmake
+++ b/Modules/CMakeDetermineCXXCompiler.cmake
@@ -58,7 +58,7 @@ else()
 
     # finally list compilers to try
     if(NOT CMAKE_CXX_COMPILER_INIT)
-      set(CMAKE_CXX_COMPILER_LIST CC ${_CMAKE_TOOLCHAIN_PREFIX}c++ ${_CMAKE_TOOLCHAIN_PREFIX}g++ aCC cl bcc xlC clang++)
+      set(CMAKE_CXX_COMPILER_LIST CC ${_CMAKE_TOOLCHAIN_PREFIX}c++ ${_CMAKE_TOOLCHAIN_PREFIX}g++ aCC cl bcc xlC icpx icx clang++)
     endif()
 
     _cmake_find_compiler(CXX)
@@ -131,7 +131,8 @@ else()
     # variable but are not aware of CMAKE_CXX_COMPILER_FRONTEND_VARIANT.
     # They pre-date our support for the GNU-like variant targeting the
     # MSVC ABI so we do not consider that here.
-    if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
+    if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang"
+      OR "x${CMAKE_CXX_COMPILER_ID}" STREQUAL "xIntelLLVM")
       if("x${CMAKE_CXX_SIMULATE_ID}" STREQUAL "xMSVC")
         set(CMAKE_CXX_COMPILER_FRONTEND_VARIANT "MSVC")
       else()
diff --git a/Modules/CMakeDetermineCompilerId.cmake b/Modules/CMakeDetermineCompilerId.cmake
index d07db70..90697f0 100644
--- a/Modules/CMakeDetermineCompilerId.cmake
+++ b/Modules/CMakeDetermineCompilerId.cmake
@@ -164,7 +164,8 @@ function(CMAKE_DETERMINE_COMPILER_ID lang flagvar src)
   endif()
 
   set(_variant "")
-  if("x${CMAKE_${lang}_COMPILER_ID}" STREQUAL "xClang")
+  if("x${CMAKE_${lang}_COMPILER_ID}" STREQUAL "xClang"
+    OR "x${CMAKE_${lang}_COMPILER_ID}" STREQUAL "xIntelLLVM")
     if("x${CMAKE_${lang}_SIMULATE_ID}" STREQUAL "xMSVC")
       if(CMAKE_GENERATOR MATCHES "Visual Studio")
         set(CMAKE_${lang}_COMPILER_FRONTEND_VARIANT "MSVC")
diff --git a/Modules/CMakeDetermineFortranCompiler.cmake b/Modules/CMakeDetermineFortranCompiler.cmake
index 8a57408..d7d032c 100644
--- a/Modules/CMakeDetermineFortranCompiler.cmake
+++ b/Modules/CMakeDetermineFortranCompiler.cmake
@@ -59,6 +59,8 @@ else()
       #  af77: Apogee F77 compiler for Intergraph hardware running CLIX
       #  epcf90: "Edinburgh Portable Compiler" F90
       #  fort: Compaq (now HP) Fortran 90/95 compiler for Tru64 and Linux/Alpha
+      #  ifx: Intel Fortran LLVM-based compiler
+      #  ifort: Intel Classic Fortran compiler
       #  ifc: Intel Fortran 95 compiler for Linux/x86
       #  efc: Intel Fortran 95 compiler for IA64
       #  nagfor: NAG Fortran compiler
@@ -68,14 +70,14 @@ else()
       #  so if you paid for a compiler it is picked by default.
       if(CMAKE_HOST_WIN32)
         set(CMAKE_Fortran_COMPILER_LIST
-          ifort pgf95 pgfortran lf95 fort
+          ifort ifx pgf95 pgfortran lf95 fort
           flang gfortran gfortran-4 g95 f90 pgf90
           pgf77 g77 f77 nag
           )
       else()
         set(CMAKE_Fortran_COMPILER_LIST
           ftn
-          ifort ifc efc pgf95 pgfortran lf95 xlf95 fort
+          ifort ifc ifx efc pgf95 pgfortran lf95 xlf95 fort
           flang gfortran gfortran-4 g95 f90 pgf90
           frt pgf77 xlf g77 f77 nag
           )
@@ -83,7 +85,7 @@ else()
 
       # Vendor-specific compiler names.
       set(_Fortran_COMPILER_NAMES_GNU       gfortran gfortran-4 g95 g77)
-      set(_Fortran_COMPILER_NAMES_Intel     ifort ifc efc)
+      set(_Fortran_COMPILER_NAMES_Intel     ifort ifc efc ifx)
       set(_Fortran_COMPILER_NAMES_Absoft    af95 af90 af77)
       set(_Fortran_COMPILER_NAMES_PGI       pgf95 pgfortran pgf90 pgf77)
       set(_Fortran_COMPILER_NAMES_Flang     flang)
diff --git a/Modules/CMakeExtraGeneratorDetermineCompilerMacrosAndIncludeDirs.cmake b/Modules/CMakeExtraGeneratorDetermineCompilerMacrosAndIncludeDirs.cmake
index 11f4a29..f90301b 100644
--- a/Modules/CMakeExtraGeneratorDetermineCompilerMacrosAndIncludeDirs.cmake
+++ b/Modules/CMakeExtraGeneratorDetermineCompilerMacrosAndIncludeDirs.cmake
@@ -88,7 +88,7 @@ set(ENV{LANG}        C)
 
 # Now check for C, works for gcc and Intel compiler at least
 if (NOT CMAKE_EXTRA_GENERATOR_C_SYSTEM_INCLUDE_DIRS)
-  if (CMAKE_C_COMPILER_ID MATCHES GNU  OR  CMAKE_C_COMPILER_ID MATCHES Intel  OR  CMAKE_C_COMPILER_ID MATCHES Clang)
+  if (CMAKE_C_COMPILER_ID MATCHES GNU  OR  CMAKE_C_COMPILER_ID MATCHES "Intel"  OR  CMAKE_C_COMPILER_ID MATCHES Clang)
     _DETERMINE_GCC_SYSTEM_INCLUDE_DIRS(c _dirs _defines)
     set(CMAKE_EXTRA_GENERATOR_C_SYSTEM_INCLUDE_DIRS "${_dirs}" CACHE INTERNAL "C compiler system include directories")
     set(CMAKE_EXTRA_GENERATOR_C_SYSTEM_DEFINED_MACROS "${_defines}" CACHE INTERNAL "C compiler system defined macros")
@@ -99,7 +99,7 @@ endif ()
 
 # And now the same for C++
 if (NOT CMAKE_EXTRA_GENERATOR_CXX_SYSTEM_INCLUDE_DIRS)
-  if ("${CMAKE_CXX_COMPILER_ID}" MATCHES GNU  OR  "${CMAKE_CXX_COMPILER_ID}" MATCHES Intel  OR  "${CMAKE_CXX_COMPILER_ID}" MATCHES Clang)
+  if ("${CMAKE_CXX_COMPILER_ID}" MATCHES GNU  OR  "${CMAKE_CXX_COMPILER_ID}" MATCHES "Intel"  OR  "${CMAKE_CXX_COMPILER_ID}" MATCHES Clang)
     _DETERMINE_GCC_SYSTEM_INCLUDE_DIRS(c++ _dirs _defines)
     set(CMAKE_EXTRA_GENERATOR_CXX_SYSTEM_INCLUDE_DIRS "${_dirs}" CACHE INTERNAL "CXX compiler system include directories")
     set(CMAKE_EXTRA_GENERATOR_CXX_SYSTEM_DEFINED_MACROS "${_defines}" CACHE INTERNAL "CXX compiler system defined macros")
diff --git a/Modules/CMakeFortranCompilerId.F.in b/Modules/CMakeFortranCompilerId.F.in
index 6ef798f..1cc08df 100644
--- a/Modules/CMakeFortranCompilerId.F.in
+++ b/Modules/CMakeFortranCompilerId.F.in
@@ -22,7 +22,21 @@
        PRINT *, 'INFO:simulate_version[013.00]'
 # endif
 #endif
-#if defined(__INTEL_COMPILER) || defined(__ICC)
+#if defined(__INTEL_LLVM_COMPILER)
+        PRINT *, 'INFO:compiler[IntelLLVM]'
+! __INTEL_LLVM_COMPILER = VVVVRP prior to 2021.2.0, VVVVRRPP for 2021.2.0 and
+! later.  Look for 6 digit vs. 8 digit version number to decide encoding.
+! VVVV is no smaller than the current year when a versio is released.
+# if __INTEL_LLVM_COMPILER < 1000000
+#  define COMPILER_VERSION_MAJOR DEC(__INTEL_LLVM_COMPILER/100)
+#  define COMPILER_VERSION_MINOR DEC(__INTEL_LLVM_COMPILER/10 % 10)
+#  define COMPILER_VERSION_PATCH DEC(__INTEL_LLVM_COMPILER    % 10)
+# else
+#  define COMPILER_VERSION_MAJOR DEC(__INTEL_LLVM_COMPILER/10000)
+#  define COMPILER_VERSION_MINOR DEC(__INTEL_LLVM_COMPILER/100 % 100)
+#  define COMPILER_VERSION_PATCH DEC(__INTEL_LLVM_COMPILER     % 100)
+# endif
+#elif defined(__INTEL_COMPILER) || defined(__ICC)
         PRINT *, 'INFO:compiler[Intel]'
 # define COMPILER_VERSION_MAJOR DEC(__INTEL_COMPILER/100)
 # define COMPILER_VERSION_MINOR DEC(__INTEL_COMPILER/10 % 10)
diff --git a/Modules/CMakeTestGNU.c b/Modules/CMakeTestGNU.c
index 933e5a2..7dcafde 100644
--- a/Modules/CMakeTestGNU.c
+++ b/Modules/CMakeTestGNU.c
@@ -1,4 +1,5 @@
-#if defined(__GNUC__) && !defined(__INTEL_COMPILER)
+#if defined(__GNUC__) &&                                                      \
+  !(defined(__INTEL_COMPILER) || defined(__INTEL_LLVM_COMPILER))
 void THIS_IS_GNU();
 #endif
 #ifdef __MINGW32__
diff --git a/Modules/Compiler/IntelLLVM-ASM.cmake b/Modules/Compiler/IntelLLVM-ASM.cmake
new file mode 100644
index 0000000..c258a0a
--- /dev/null
+++ b/Modules/Compiler/IntelLLVM-ASM.cmake
@@ -0,0 +1,12 @@
+include(Compiler/IntelLLVM)
+__compiler_intel_llvm(ASM)
+
+string(APPEND CMAKE_ASM_FLAGS_MINSIZEREL_INIT " -DNDEBUG")
+string(APPEND CMAKE_ASM_FLAGS_RELEASE_INIT " -DNDEBUG")
+string(APPEND CMAKE_ASM_FLAGS_RELWITHDEBINFO_INIT " -DNDEBUG")
+
+if(UNIX)
+  set(CMAKE_ASM_SOURCE_FILE_EXTENSIONS s;S)
+else()
+  set(CMAKE_ASM_SOURCE_FILE_EXTENSIONS asm)
+endif()
diff --git a/Modules/Compiler/IntelLLVM-C.cmake b/Modules/Compiler/IntelLLVM-C.cmake
new file mode 100644
index 0000000..0ad2f0d
--- /dev/null
+++ b/Modules/Compiler/IntelLLVM-C.cmake
@@ -0,0 +1,63 @@
+include(Compiler/IntelLLVM)
+__compiler_intel_llvm(C)
+
+if("x${CMAKE_C_COMPILER_FRONTEND_VARIANT}" STREQUAL "xMSVC")
+  set(CMAKE_C_COMPILE_OPTIONS_EXPLICIT_LANGUAGE -TC)
+  set(CMAKE_C_CLANG_TIDY_DRIVER_MODE "cl")
+  if((NOT DEFINED CMAKE_DEPENDS_USE_COMPILER OR CMAKE_DEPENDS_USE_COMPILER)
+      AND CMAKE_GENERATOR MATCHES "Makefiles|WMake"
+      AND CMAKE_DEPFILE_FLAGS_C)
+    set(CMAKE_C_DEPENDS_USE_COMPILER TRUE)
+  endif()
+else()
+  set(CMAKE_C_COMPILE_OPTIONS_EXPLICIT_LANGUAGE -x c)
+  if((NOT DEFINED CMAKE_DEPENDS_USE_COMPILER OR CMAKE_DEPENDS_USE_COMPILER)
+      AND CMAKE_GENERATOR MATCHES "Makefiles|WMake"
+      AND CMAKE_DEPFILE_FLAGS_C)
+    # dependencies are computed by the compiler itself
+    set(CMAKE_C_DEPFILE_FORMAT gcc)
+    set(CMAKE_C_DEPENDS_USE_COMPILER TRUE)
+  endif()
+
+  string(APPEND CMAKE_C_FLAGS_MINSIZEREL_INIT " -DNDEBUG")
+  string(APPEND CMAKE_C_FLAGS_RELEASE_INIT " -DNDEBUG")
+  string(APPEND CMAKE_C_FLAGS_RELWITHDEBINFO_INIT " -DNDEBUG")
+endif()
+
+set(CMAKE_C90_STANDARD__HAS_FULL_SUPPORT ON)
+set(CMAKE_C99_STANDARD__HAS_FULL_SUPPORT ON)
+set(CMAKE_C11_STANDARD__HAS_FULL_SUPPORT ON)
+set(CMAKE_C17_STANDARD__HAS_FULL_SUPPORT ON)
+
+if(NOT "x${CMAKE_C_SIMULATE_ID}" STREQUAL "xMSVC")
+  set(CMAKE_C90_STANDARD_COMPILE_OPTION "-std=c90")
+  set(CMAKE_C90_EXTENSION_COMPILE_OPTION "-std=gnu90")
+
+  set(CMAKE_C99_STANDARD_COMPILE_OPTION "-std=c99")
+  set(CMAKE_C99_EXTENSION_COMPILE_OPTION "-std=gnu99")
+
+  set(CMAKE_C11_STANDARD_COMPILE_OPTION "-std=c11")
+  set(CMAKE_C11_EXTENSION_COMPILE_OPTION "-std=gnu11")
+
+  set(CMAKE_C17_STANDARD_COMPILE_OPTION "-std=c17")
+  set(CMAKE_C17_EXTENSION_COMPILE_OPTION "-std=gnu17")
+else()
+  # clang-cl doesn't have any of these
+  set(CMAKE_C90_STANDARD_COMPILE_OPTION "")
+  set(CMAKE_C90_EXTENSION_COMPILE_OPTION "")
+
+  set(CMAKE_C99_STANDARD_COMPILE_OPTION "")
+  set(CMAKE_C99_EXTENSION_COMPILE_OPTION "")
+
+  set(CMAKE_C11_STANDARD_COMPILE_OPTION "")
+  set(CMAKE_C11_EXTENSION_COMPILE_OPTION "")
+
+  set(CMAKE_C17_STANDARD_COMPILE_OPTION "")
+  set(CMAKE_C17_EXTENSION_COMPILE_OPTION "")
+endif()
+
+if(NOT "x${CMAKE_C_SIMULATE_ID}" STREQUAL "xMSVC")
+  __compiler_check_default_language_standard(C 2020 17)
+else()
+  set(CMAKE_C_STANDARD_DEFAULT "")
+endif()
diff --git a/Modules/Compiler/IntelLLVM-CXX.cmake b/Modules/Compiler/IntelLLVM-CXX.cmake
new file mode 100644
index 0000000..4c0c26e
--- /dev/null
+++ b/Modules/Compiler/IntelLLVM-CXX.cmake
@@ -0,0 +1,69 @@
+include(Compiler/IntelLLVM)
+__compiler_intel_llvm(CXX)
+
+if("x${CMAKE_CXX_COMPILER_FRONTEND_VARIANT}" STREQUAL "xMSVC")
+  set(CMAKE_CXX_COMPILE_OPTIONS_EXPLICIT_LANGUAGE -TP)
+  set(CMAKE_CXX_CLANG_TIDY_DRIVER_MODE "cl")
+  if((NOT DEFINED CMAKE_DEPENDS_USE_COMPILER OR CMAKE_DEPENDS_USE_COMPILER)
+      AND CMAKE_GENERATOR MATCHES "Makefiles|WMake"
+      AND CMAKE_DEPFILE_FLAGS_CXX)
+    set(CMAKE_CXX_DEPENDS_USE_COMPILER TRUE)
+  endif()
+else()
+  set(CMAKE_CXX_COMPILE_OPTIONS_EXPLICIT_LANGUAGE -x c++)
+  if((NOT DEFINED CMAKE_DEPENDS_USE_COMPILER OR CMAKE_DEPENDS_USE_COMPILER)
+      AND CMAKE_GENERATOR MATCHES "Makefiles|WMake"
+      AND CMAKE_DEPFILE_FLAGS_CXX)
+    # dependencies are computed by the compiler itself
+    set(CMAKE_CXX_DEPFILE_FORMAT gcc)
+    set(CMAKE_CXX_DEPENDS_USE_COMPILER TRUE)
+  endif()
+
+  set(CMAKE_CXX_COMPILE_OPTIONS_VISIBILITY_INLINES_HIDDEN "-fvisibility-inlines-hidden")
+
+  string(APPEND CMAKE_CXX_FLAGS_MINSIZEREL_INIT " -DNDEBUG")
+  string(APPEND CMAKE_CXX_FLAGS_RELEASE_INIT " -DNDEBUG")
+  string(APPEND CMAKE_CXX_FLAGS_RELWITHDEBINFO_INIT " -DNDEBUG")
+endif()
+
+set(CMAKE_CXX98_STANDARD__HAS_FULL_SUPPORT ON)
+set(CMAKE_CXX11_STANDARD__HAS_FULL_SUPPORT ON)
+set(CMAKE_CXX14_STANDARD__HAS_FULL_SUPPORT ON)
+
+if(NOT "x${CMAKE_CXX_SIMULATE_ID}" STREQUAL "xMSVC")
+  set(CMAKE_CXX98_STANDARD_COMPILE_OPTION  "-std=c++98")
+  set(CMAKE_CXX98_EXTENSION_COMPILE_OPTION "-std=gnu++98")
+
+  set(CMAKE_CXX11_STANDARD_COMPILE_OPTION  "-std=c++11")
+  set(CMAKE_CXX11_EXTENSION_COMPILE_OPTION "-std=gnu++11")
+
+  set(CMAKE_CXX14_STANDARD_COMPILE_OPTION  "-std=c++14")
+  set(CMAKE_CXX14_EXTENSION_COMPILE_OPTION "-std=gnu++14")
+
+  set(CMAKE_CXX17_STANDARD_COMPILE_OPTION  "-std=c++17")
+  set(CMAKE_CXX17_EXTENSION_COMPILE_OPTION "-std=gnu++17")
+
+  set(CMAKE_CXX20_STANDARD_COMPILE_OPTION  "-std=c++20")
+  set(CMAKE_CXX20_EXTENSION_COMPILE_OPTION "-std=gnu++20")
+else()
+  set(CMAKE_CXX98_STANDARD_COMPILE_OPTION  "")
+  set(CMAKE_CXX98_EXTENSION_COMPILE_OPTION "")
+
+  set(CMAKE_CXX11_STANDARD_COMPILE_OPTION  "-Qstd=c++11")
+  set(CMAKE_CXX11_EXTENSION_COMPILE_OPTION "-Qstd=c++11")
+
+  set(CMAKE_CXX14_STANDARD_COMPILE_OPTION  "-Qstd=c++14")
+  set(CMAKE_CXX14_EXTENSION_COMPILE_OPTION "-Qstd=c++14")
+
+  set(CMAKE_CXX17_STANDARD_COMPILE_OPTION  "-Qstd=c++17")
+  set(CMAKE_CXX17_EXTENSION_COMPILE_OPTION "-Qstd=c++17")
+
+  set(CMAKE_CXX20_STANDARD_COMPILE_OPTION  "-Qstd=c++20")
+  set(CMAKE_CXX20_EXTENSION_COMPILE_OPTION "-Qstd=c++20")
+endif()
+
+if(NOT "x${CMAKE_CXX_SIMULATE_ID}" STREQUAL "xMSVC")
+  __compiler_check_default_language_standard(CXX 2020 14)
+else()
+  set(CMAKE_CXX_STANDARD_DEFAULT "")
+endif()
diff --git a/Modules/Compiler/IntelLLVM-DetermineCompiler.cmake b/Modules/Compiler/IntelLLVM-DetermineCompiler.cmake
new file mode 100644
index 0000000..124dafe
--- /dev/null
+++ b/Modules/Compiler/IntelLLVM-DetermineCompiler.cmake
@@ -0,0 +1,41 @@
+
+set(_compiler_id_pp_test "(defined(__clang__) && defined(__INTEL_CLANG_COMPILER)) || defined(__INTEL_LLVM_COMPILER)")
+
+set(_compiler_id_version_compute "
+/* __INTEL_LLVM_COMPILER = VVVVRP prior to 2021.2.0, VVVVRRPP for 2021.2.0 and
+ * later.  Look for 6 digit vs. 8 digit version number to decide encoding.
+ * VVVV is no smaller than the current year when a versio is released.
+ */
+#if __INTEL_LLVM_COMPILER < 1000000L
+# define @PREFIX@COMPILER_VERSION_MAJOR @MACRO_DEC@(__INTEL_LLVM_COMPILER/100)
+# define @PREFIX@COMPILER_VERSION_MINOR @MACRO_DEC@(__INTEL_LLVM_COMPILER/10 % 10)
+# define @PREFIX@COMPILER_VERSION_PATCH @MACRO_DEC@(__INTEL_LLVM_COMPILER    % 10)
+#else
+# define @PREFIX@COMPILER_VERSION_MAJOR @MACRO_DEC@(__INTEL_LLVM_COMPILER/10000)
+# define @PREFIX@COMPILER_VERSION_MINOR @MACRO_DEC@(__INTEL_LLVM_COMPILER/100 % 100)
+# define @PREFIX@COMPILER_VERSION_PATCH @MACRO_DEC@(__INTEL_LLVM_COMPILER     % 100)
+#endif
+#if defined(_MSC_VER)
+  /* _MSC_VER = VVRR */
+# define @PREFIX@SIMULATE_VERSION_MAJOR @MACRO_DEC@(_MSC_VER / 100)
+# define @PREFIX@SIMULATE_VERSION_MINOR @MACRO_DEC@(_MSC_VER % 100)
+#endif
+#if defined(__GNUC__)
+# define @PREFIX@SIMULATE_VERSION_MAJOR @MACRO_DEC@(__GNUC__)
+#elif defined(__GNUG__)
+# define @PREFIX@SIMULATE_VERSION_MAJOR @MACRO_DEC@(__GNUG__)
+#endif
+#if defined(__GNUC_MINOR__)
+# define @PREFIX@SIMULATE_VERSION_MINOR @MACRO_DEC@(__GNUC_MINOR__)
+#endif
+#if defined(__GNUC_PATCHLEVEL__)
+# define @PREFIX@SIMULATE_VERSION_PATCH @MACRO_DEC@(__GNUC_PATCHLEVEL__)
+#endif")
+
+set(_compiler_id_simulate "
+#if defined(_MSC_VER)
+# define @PREFIX@SIMULATE_ID \"MSVC\"
+#endif
+#if defined(__GNUC__)
+# define @PREFIX@SIMULATE_ID \"GNU\"
+#endif")
diff --git a/Modules/Compiler/IntelLLVM-Fortran.cmake b/Modules/Compiler/IntelLLVM-Fortran.cmake
new file mode 100644
index 0000000..3dfa099
--- /dev/null
+++ b/Modules/Compiler/IntelLLVM-Fortran.cmake
@@ -0,0 +1,19 @@
+include(Compiler/IntelLLVM)
+__compiler_intel_llvm(Fortran)
+
+set(CMAKE_Fortran_SUBMODULE_SEP "@")
+set(CMAKE_Fortran_SUBMODULE_EXT ".smod")
+
+set(CMAKE_Fortran_MODDIR_FLAG "-module ")
+set(CMAKE_Fortran_FORMAT_FIXED_FLAG "-fixed")
+set(CMAKE_Fortran_FORMAT_FREE_FLAG "-free")
+
+set(CMAKE_Fortran_COMPILE_WITH_DEFINES 1)
+
+set(CMAKE_Fortran_CREATE_PREPROCESSED_SOURCE "<CMAKE_Fortran_COMPILER> <DEFINES> <INCLUDES> <FLAGS> -E <SOURCE> > <PREPROCESSED_SOURCE>")
+set(CMAKE_Fortran_CREATE_ASSEMBLY_SOURCE "<CMAKE_Fortran_COMPILER> <DEFINES> <INCLUDES> <FLAGS> -S <SOURCE> -o <ASSEMBLY_SOURCE>")
+
+set(CMAKE_Fortran_PREPROCESS_SOURCE
+  "<CMAKE_Fortran_COMPILER> -fpp <DEFINES> <INCLUDES> <FLAGS> -E <SOURCE> > <PREPROCESSED_SOURCE>")
+set(CMAKE_Fortran_COMPILE_OPTIONS_PREPROCESS_ON "-fpp")
+set(CMAKE_Fortran_COMPILE_OPTIONS_PREPROCESS_OFF "-nofpp")
diff --git a/Modules/Compiler/IntelLLVM.cmake b/Modules/Compiler/IntelLLVM.cmake
new file mode 100644
index 0000000..43eb13a
--- /dev/null
+++ b/Modules/Compiler/IntelLLVM.cmake
@@ -0,0 +1,93 @@
+# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
+
+# This module is shared by multiple languages; use include blocker.
+if(__COMPILER_LLVM_INTEL)
+  return()
+endif()
+set(__COMPILER_LLVM_INTEL 1)
+
+include(Compiler/CMakeCommonCompilerMacros)
+
+set(__pch_header_C "c-header")
+set(__pch_header_CXX "c++-header")
+set(__pch_header_OBJC "objective-c-header")
+set(__pch_header_OBJCXX "objective-c++-header")
+
+if(CMAKE_HOST_WIN32)
+  # MSVC-like
+  macro(__compiler_intel_llvm lang)
+    set(CMAKE_INCLUDE_SYSTEM_FLAG_${lang} "-imsvc ")
+    if(NOT "x${lang}" STREQUAL "xFortran")
+      set(CMAKE_${lang}_COMPILE_OPTIONS_INVALID_PCH -Winvalid-pch)
+    endif()
+  endmacro()
+else()
+  # GNU-like
+  macro(__compiler_intel_llvm lang)
+    set(CMAKE_${lang}_VERBOSE_FLAG "-v")
+
+    string(APPEND CMAKE_${lang}_FLAGS_INIT " ")
+    string(APPEND CMAKE_${lang}_FLAGS_DEBUG_INIT " -g")
+    string(APPEND CMAKE_${lang}_FLAGS_MINSIZEREL_INIT " -Os")
+    string(APPEND CMAKE_${lang}_FLAGS_RELEASE_INIT " -O3")
+    string(APPEND CMAKE_${lang}_FLAGS_RELWITHDEBINFO_INIT " -O2 -g")
+
+    set(_CMAKE_${lang}_PIE_MAY_BE_SUPPORTED_BY_LINKER YES)
+    set(CMAKE_${lang}_COMPILE_OPTIONS_PIC "-fPIC")
+    set(CMAKE_${lang}_COMPILE_OPTIONS_PIE "-fPIE")
+    set(CMAKE_${lang}_LINK_OPTIONS_PIE ${CMAKE_${lang}_COMPILE_OPTIONS_PIE} "-pie")
+    set(CMAKE_${lang}_LINK_OPTIONS_NO_PIE "-no-pie")
+
+    set(CMAKE_SHARED_LIBRARY_${lang}_FLAGS "-fPIC")
+    set(CMAKE_SHARED_LIBRARY_CREATE_${lang}_FLAGS "-shared")
+
+    set(CMAKE_${lang}_LINKER_WRAPPER_FLAG "-Wl,")
+    set(CMAKE_${lang}_LINKER_WRAPPER_FLAG_SEP ",")
+
+    # distcc does not transform -o to -MT when invoking the preprocessor
+    # internally, as it ought to.  Work around this bug by setting -MT here
+    # even though it isn't strictly necessary.
+    set(CMAKE_DEPFILE_FLAGS_${lang} "-MD -MT <DEP_TARGET> -MF <DEP_FILE>")
+
+    set(CMAKE_INCLUDE_SYSTEM_FLAG_${lang} "-isystem ")
+    set(CMAKE_${lang}_COMPILE_OPTIONS_VISIBILITY "-fvisibility=")
+    set(CMAKE_${lang}_COMPILE_OPTIONS_TARGET "--target=")
+    set(CMAKE_${lang}_COMPILE_OPTIONS_SYSROOT "--sysroot=")
+    set(CMAKE_${lang}_COMPILE_OPTIONS_EXTERNAL_TOOLCHAIN "--gcc-toolchain=")
+    set(CMAKE_${lang}_LINKER_WRAPPER_FLAG "-Xlinker" " ")
+    set(CMAKE_${lang}_LINKER_WRAPPER_FLAG_SEP)
+
+    set(_CMAKE_${lang}_IPO_SUPPORTED_BY_CMAKE YES)
+    set(_CMAKE_${lang}_IPO_MAY_BE_SUPPORTED_BY_COMPILER YES)
+    set(CMAKE_${lang}_COMPILE_OPTIONS_IPO "-flto=thin")
+    set(CMAKE_${lang}_ARCHIVE_CREATE_IPO "\"${CMAKE_${lang}_COMPILER_AR}\" cr <TARGET> <LINK_FLAGS> <OBJECTS>")
+    set(CMAKE_${lang}_ARCHIVE_APPEND_IPO "\"${CMAKE_${lang}_COMPILER_AR}\" r <TARGET> <LINK_FLAGS> <OBJECTS>")
+    set(CMAKE_${lang}_ARCHIVE_FINISH_IPO "\"${CMAKE_${lang}_COMPILER_RANLIB}\" <TARGET>")
+
+    set(CMAKE_${lang}_CREATE_PREPROCESSED_SOURCE "<CMAKE_${lang}_COMPILER> <DEFINES> <INCLUDES> <FLAGS> -E <SOURCE> > <PREPROCESSED_SOURCE>")
+    set(CMAKE_${lang}_CREATE_ASSEMBLY_SOURCE "<CMAKE_${lang}_COMPILER> <DEFINES> <INCLUDES> <FLAGS> -S <SOURCE> -o <ASSEMBLY_SOURCE>")
+
+    set(CMAKE_${lang}_COMPILER_PREDEFINES_COMMAND "${CMAKE_${lang}_COMPILER}")
+    if(CMAKE_${lang}_COMPILER_ARG1)
+      separate_arguments(_COMPILER_ARGS NATIVE_COMMAND "${CMAKE_${lang}_COMPILER_ARG1}")
+      list(APPEND CMAKE_${lang}_COMPILER_PREDEFINES_COMMAND ${_COMPILER_ARGS})
+      unset(_COMPILER_ARGS)
+    endif()
+    list(APPEND CMAKE_${lang}_COMPILER_PREDEFINES_COMMAND "-dM" "-E" "-c" "${CMAKE_ROOT}/Modules/CMakeCXXCompilerABI.cpp")
+    if(CMAKE_${lang}_COMPILER_TARGET)
+      list(APPEND CMAKE_${lang}_COMPILER_PREDEFINES_COMMAND "--target=${CMAKE_${lang}_COMPILER_TARGET}")
+    endif()
+
+    if(NOT "x${lang}" STREQUAL "xFortran")
+      # Precompile Headers
+      set(CMAKE_PCH_EXTENSION .pch)
+      set(CMAKE_PCH_PROLOGUE "#pragma clang system_header")
+      set(CMAKE_${lang}_COMPILE_OPTIONS_INSTANTIATE_TEMPLATES_PCH -fpch-instantiate-templates)
+      set(CMAKE_${lang}_COMPILE_OPTIONS_INVALID_PCH -Winvalid-pch)
+      set(CMAKE_${lang}_COMPILE_OPTIONS_USE_PCH -Xclang -include-pch -Xclang <PCH_FILE> -Xclang -include -Xclang <PCH_HEADER>)
+      set(CMAKE_${lang}_COMPILE_OPTIONS_CREATE_PCH -Xclang -emit-pch -Xclang -include -Xclang <PCH_HEADER> -x ${__pch_header_${lang}})
+    endif()
+  endmacro()
+endif()
diff --git a/Modules/FindBLAS.cmake b/Modules/FindBLAS.cmake
index 01d0236..4cf812b 100644
--- a/Modules/FindBLAS.cmake
+++ b/Modules/FindBLAS.cmake
@@ -842,6 +842,9 @@ if(BLA_VENDOR MATCHES "ACML" OR BLA_VENDOR STREQUAL "All")
     if(CMAKE_Fortran_COMPILER_ID STREQUAL "Intel")
       set(_ACML_COMPILER32 "ifort32")
       set(_ACML_COMPILER64 "ifort64")
+    elseif(CMAKE_Fortran_COMPILER_ID STREQUAL "IntelLLVM")
+      # 32-bit not supported
+      set(_ACML_COMPILER64 "ifx")
     elseif(CMAKE_Fortran_COMPILER_ID STREQUAL "SunPro")
       set(_ACML_COMPILER32 "sun32")
       set(_ACML_COMPILER64 "sun64")
diff --git a/Modules/FindBoost.cmake b/Modules/FindBoost.cmake
index e41e864..6ee425b 100644
--- a/Modules/FindBoost.cmake
+++ b/Modules/FindBoost.cmake
@@ -853,7 +853,8 @@ endfunction()
 # Guesses Boost's compiler prefix used in built library names
 # Returns the guess by setting the variable pointed to by _ret
 function(_Boost_GUESS_COMPILER_PREFIX _ret)
-  if("x${CMAKE_CXX_COMPILER_ID}" STREQUAL "xIntel")
+  if("x${CMAKE_CXX_COMPILER_ID}" STREQUAL "xIntel"
+      OR "x${CMAKE_CXX_COMPILER_ARCHITECTURE_ID}" STREQUAL "xIntelLLVM")
     if(WIN32)
       set (_boost_COMPILER "-iw")
     else()
@@ -1891,7 +1892,8 @@ endif()
 if(WIN32 AND Boost_USE_DEBUG_RUNTIME)
   if("x${CMAKE_CXX_COMPILER_ID}" STREQUAL "xMSVC"
           OR "x${CMAKE_CXX_COMPILER_ID}" STREQUAL "xClang"
-          OR "x${CMAKE_CXX_COMPILER_ID}" STREQUAL "xIntel")
+          OR "x${CMAKE_CXX_COMPILER_ID}" STREQUAL "xIntel"
+          OR "x${CMAKE_CXX_COMPILER_ID}" STREQUAL "xIntelLLVM")
     string(APPEND _boost_DEBUG_ABI_TAG "g")
   endif()
 endif()
diff --git a/Modules/FindMPI.cmake b/Modules/FindMPI.cmake
index 8476823..8cc39ac 100644
--- a/Modules/FindMPI.cmake
+++ b/Modules/FindMPI.cmake
@@ -294,6 +294,11 @@ if(WIN32)
   set(_MPI_Intel_CXX_COMPILER_NAMES          mpiicpc.bat)
   set(_MPI_Intel_Fortran_COMPILER_NAMES      mpiifort.bat mpif77.bat mpif90.bat)
 
+  # Intel MPI compiler names
+  set(_MPI_IntelLLVM_C_COMPILER_NAMES            mpiicc.bat)
+  set(_MPI_IntelLLVM_CXX_COMPILER_NAMES          mpiicpc.bat)
+  set(_MPI_IntelLLVM_Fortran_COMPILER_NAMES      mpiifort.bat mpif77.bat mpif90.bat)
+
   # Intel MPI compiler names for MSMPI
   set(_MPI_MSVC_C_COMPILER_NAMES             mpicl.bat)
   set(_MPI_MSVC_CXX_COMPILER_NAMES           mpicl.bat)
@@ -302,6 +307,11 @@ else()
   set(_MPI_Intel_C_COMPILER_NAMES            mpiicc)
   set(_MPI_Intel_CXX_COMPILER_NAMES          mpiicpc  mpiicxx mpiic++)
   set(_MPI_Intel_Fortran_COMPILER_NAMES      mpiifort mpiif95 mpiif90 mpiif77)
+
+  # Intel compiler names
+  set(_MPI_IntelLLVM_C_COMPILER_NAMES            mpiicc)
+  set(_MPI_IntelLLVM_CXX_COMPILER_NAMES          mpiicpc  mpiicxx mpiic++)
+  set(_MPI_IntelLLVM_Fortran_COMPILER_NAMES      mpiifort mpiif95 mpiif90 mpiif77)
 endif()
 
 # PGI compiler names
@@ -327,7 +337,7 @@ set(_MPI_XL_Fortran_COMPILER_NAMES         mpixlf95   mpixlf95_r mpxlf95 mpxlf95
 # pick up the right settings for it.
 foreach (LANG IN ITEMS C CXX Fortran)
   set(_MPI_${LANG}_COMPILER_NAMES "")
-  foreach (id IN ITEMS GNU Intel MSVC PGI XL)
+  foreach (id IN ITEMS GNU Intel IntelLLVM MSVC PGI XL)
     if (NOT CMAKE_${LANG}_COMPILER_ID OR CMAKE_${LANG}_COMPILER_ID STREQUAL id)
       foreach(_COMPILER_NAME IN LISTS _MPI_${id}_${LANG}_COMPILER_NAMES)
         list(APPEND _MPI_${LANG}_COMPILER_NAMES ${_COMPILER_NAME}${MPI_EXECUTABLE_SUFFIX})
diff --git a/Modules/FindOpenMP.cmake b/Modules/FindOpenMP.cmake
index 11c6050..a1ffc25 100644
--- a/Modules/FindOpenMP.cmake
+++ b/Modules/FindOpenMP.cmake
@@ -113,6 +113,7 @@ function(_OPENMP_FLAG_CANDIDATES LANG)
     else()
       set(OMP_FLAG_Intel "-qopenmp")
     endif()
+    set(OMP_FLAG_IntelLLVM "-fiopenmp")
     set(OMP_FLAG_MSVC "-openmp")
     set(OMP_FLAG_PathScale "-openmp")
     set(OMP_FLAG_NAG "-openmp")
diff --git a/Modules/GenerateExportHeader.cmake b/Modules/GenerateExportHeader.cmake
index 2c4572f..a9a9c59 100644
--- a/Modules/GenerateExportHeader.cmake
+++ b/Modules/GenerateExportHeader.cmake
@@ -221,7 +221,7 @@ macro(_test_compiler_hidden_visibility)
     set(GCC_TOO_OLD TRUE)
   elseif(CMAKE_COMPILER_IS_GNUCC AND CMAKE_C_COMPILER_VERSION VERSION_LESS "4.2")
     set(GCC_TOO_OLD TRUE)
-  elseif(CMAKE_CXX_COMPILER_ID MATCHES Intel AND CMAKE_CXX_COMPILER_VERSION VERSION_LESS "12.0")
+  elseif(CMAKE_CXX_COMPILER_ID STREQUAL "Intel" AND CMAKE_CXX_COMPILER_VERSION VERSION_LESS "12.0")
     set(_INTEL_TOO_OLD TRUE)
   endif()
 
diff --git a/Modules/InstallRequiredSystemLibraries.cmake b/Modules/InstallRequiredSystemLibraries.cmake
index a39393dc..2d08e08 100644
--- a/Modules/InstallRequiredSystemLibraries.cmake
+++ b/Modules/InstallRequiredSystemLibraries.cmake
@@ -71,7 +71,7 @@ cmake_policy(SET CMP0054 NEW) # if() quoted variables not dereferenced
 set(_IRSL_HAVE_Intel FALSE)
 set(_IRSL_HAVE_MSVC FALSE)
 foreach(LANG IN ITEMS C CXX Fortran)
-  if("${CMAKE_${LANG}_COMPILER_ID}" STREQUAL "Intel")
+  if("${CMAKE_${LANG}_COMPILER_ID}" MATCHES "Intel")
     if(NOT _IRSL_HAVE_Intel)
       get_filename_component(_Intel_basedir "${CMAKE_${LANG}_COMPILER}" PATH)
       if(CMAKE_SIZEOF_VOID_P EQUAL 8)
@@ -637,10 +637,10 @@ if(_IRSL_HAVE_Intel)
 
       list(APPEND __install_libs "${_Intel_redistdir}/${__Intel_lib}")
     endforeach()
-    if(CMAKE_C_COMPILER_ID STREQUAL Intel OR CMAKE_CXX_COMPILER_ID STREQUAL Intel)
+    if(CMAKE_C_COMPILER_ID MATCHES Intel OR CMAKE_CXX_COMPILER_ID MATCHES Intel)
       list(APPEND __install_libs "${_Intel_redistdir}/libgfxoffload.dll")
     endif()
-    if(CMAKE_Fortran_COMPILER_ID STREQUAL Intel)
+    if(CMAKE_Fortran_COMPILER_ID MATCHES Intel)
       foreach(__Intel_lib IN ITEMS ifdlg100.dll libicaf.dll libifcoremd.dll libifcoremdd.dll libifcorert.dll libifcorertd.dll libifportmd.dll)
 
         list(APPEND __install_libs "${_Intel_redistdir}/${__Intel_lib}")
@@ -650,12 +650,12 @@ if(_IRSL_HAVE_Intel)
     foreach(__Intel_lib IN ITEMS libchkp.dylib libcilkrts.5.dylib libcilkrts.dylib libimf.dylib libintlc.dylib libirc.dylib libirng.dylib libsvml.dylib)
       list(APPEND __install_libs "${_Intel_redistdir}/${__Intel_lib}")
     endforeach()
-    if(CMAKE_C_COMPILER_ID STREQUAL Intel OR CMAKE_CXX_COMPILER_ID STREQUAL Intel)
+    if(CMAKE_C_COMPILER_ID MATCHES Intel OR CMAKE_CXX_COMPILER_ID MATCHES Intel)
       if(_Intel_compiler_ver VERSION_LESS 17)
         list(APPEND __install_libs "${_Intel_redistdir}/libistrconv.dylib")
       endif()
     endif()
-    if(CMAKE_Fortran_COMPILER_ID STREQUAL Intel)
+    if(CMAKE_Fortran_COMPILER_ID MATCHES Intel)
       foreach(__Intel_lib IN ITEMS libifcore.dylib libifcoremt.dylib libifport.dylib libifportmt.dylib)
 
         list(APPEND __install_libs "${_Intel_redistdir}/${__Intel_lib}")
@@ -672,7 +672,7 @@ if(_IRSL_HAVE_Intel)
         list(APPEND __install_libs "${_Intel_redistdir}/${__Intel_lib}")
       endforeach()
     endif()
-    if(CMAKE_C_COMPILER_ID STREQUAL Intel OR CMAKE_CXX_COMPILER_ID STREQUAL Intel)
+    if(CMAKE_C_COMPILER_ID MATCHES Intel OR CMAKE_CXX_COMPILER_ID MATCHES Intel)
       set(__install_dirs "${_Intel_redistdir}/irml")
       list(APPEND __install_libs "${_Intel_redistdir}/cilk_db.so")
       if(_Intel_compiler_ver VERSION_GREATER_EQUAL 15)
@@ -691,7 +691,7 @@ if(_IRSL_HAVE_Intel)
         list(APPEND __install_libs "${_Intel_redistdir}/${__Intel_lib}")
       endforeach()
     endif()
-    if(CMAKE_Fortran_COMPILER_ID STREQUAL Intel)
+    if(CMAKE_Fortran_COMPILER_ID MATCHES Intel)
       foreach(__Intel_lib IN ITEMS libicaf.so libifcore.so libifcore.so.5 libifcoremt.so libifcoremt.so.5 libifport.so libifport.so.5)
 
         list(APPEND __install_libs "${_Intel_redistdir}/${__Intel_lib}")
diff --git a/Modules/Platform/Apple-IntelLLVM-C.cmake b/Modules/Platform/Apple-IntelLLVM-C.cmake
new file mode 100644
index 0000000..8e74729
--- /dev/null
+++ b/Modules/Platform/Apple-IntelLLVM-C.cmake
@@ -0,0 +1,2 @@
+include(Platform/Apple-IntelLLVM)
+__apple_compiler_intel_llvm(C)
diff --git a/Modules/Platform/Apple-IntelLLVM-CXX.cmake b/Modules/Platform/Apple-IntelLLVM-CXX.cmake
new file mode 100644
index 0000000..38640e1
--- /dev/null
+++ b/Modules/Platform/Apple-IntelLLVM-CXX.cmake
@@ -0,0 +1,2 @@
+include(Platform/Apple-IntelLLVM)
+__apple_compiler_intel_llvm(CXX)
diff --git a/Modules/Platform/Apple-IntelLLVM-Fortran.cmake b/Modules/Platform/Apple-IntelLLVM-Fortran.cmake
new file mode 100644
index 0000000..d0486ed
--- /dev/null
+++ b/Modules/Platform/Apple-IntelLLVM-Fortran.cmake
@@ -0,0 +1,8 @@
+# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
+include(Platform/Apple-IntelLLVM)
+__apple_compiler_intel_llvm(Fortran)
+
+set(CMAKE_Fortran_OSX_COMPATIBILITY_VERSION_FLAG "-compatibility_version ")
+set(CMAKE_Fortran_OSX_CURRENT_VERSION_FLAG "-current_version ")
diff --git a/Modules/Platform/Apple-IntelLLVM.cmake b/Modules/Platform/Apple-IntelLLVM.cmake
new file mode 100644
index 0000000..2f9f0ca
--- /dev/null
+++ b/Modules/Platform/Apple-IntelLLVM.cmake
@@ -0,0 +1,17 @@
+# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
+
+# This module is shared by multiple languages; use include blocker.
+include_guard()
+
+macro(__apple_compiler_intel_llvm lang)
+  set(CMAKE_${lang}_VERBOSE_FLAG "-v -Wl,-v") # also tell linker to print verbose output
+  set(CMAKE_SHARED_LIBRARY_CREATE_${lang}_FLAGS "-dynamiclib -Wl,-headerpad_max_install_names")
+  set(CMAKE_SHARED_MODULE_CREATE_${lang}_FLAGS "-bundle -Wl,-headerpad_max_install_names")
+
+  set(CMAKE_${lang}_LINKER_WRAPPER_FLAG "-Wl,")
+  set(CMAKE_${lang}_LINKER_WRAPPER_FLAG_SEP ",")
+
+  set(CMAKE_${lang}_COMPILE_OPTIONS_VISIBILITY "-fvisibility=")
+endmacro()
diff --git a/Modules/Platform/Linux-IntelLLVM-C.cmake b/Modules/Platform/Linux-IntelLLVM-C.cmake
new file mode 100644
index 0000000..5356c4f
--- /dev/null
+++ b/Modules/Platform/Linux-IntelLLVM-C.cmake
@@ -0,0 +1,3 @@
+include(Platform/Linux-IntelLLVM)
+__linux_compiler_intel_llvm(C)
+set(CMAKE_INCLUDE_SYSTEM_FLAG_C "-isystem ")
diff --git a/Modules/Platform/Linux-IntelLLVM-CXX.cmake b/Modules/Platform/Linux-IntelLLVM-CXX.cmake
new file mode 100644
index 0000000..44ce0e8
--- /dev/null
+++ b/Modules/Platform/Linux-IntelLLVM-CXX.cmake
@@ -0,0 +1,3 @@
+include(Platform/Linux-IntelLLVM)
+__linux_compiler_intel_llvm(CXX)
+set(CMAKE_INCLUDE_SYSTEM_FLAG_CXX "-isystem ")
diff --git a/Modules/Platform/Linux-IntelLLVM-Fortran.cmake b/Modules/Platform/Linux-IntelLLVM-Fortran.cmake
new file mode 100644
index 0000000..1cd9b1f
--- /dev/null
+++ b/Modules/Platform/Linux-IntelLLVM-Fortran.cmake
@@ -0,0 +1,4 @@
+include(Platform/Linux-IntelLLVM)
+__linux_compiler_intel_llvm(Fortran)
+string(APPEND CMAKE_SHARED_LIBRARY_CREATE_Fortran_FLAGS " -nofor-main")
+set(CMAKE_SHARED_LIBRARY_LINK_Fortran_FLAGS "")
diff --git a/Modules/Platform/Linux-IntelLLVM.cmake b/Modules/Platform/Linux-IntelLLVM.cmake
new file mode 100644
index 0000000..1363b44
--- /dev/null
+++ b/Modules/Platform/Linux-IntelLLVM.cmake
@@ -0,0 +1,55 @@
+# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
+
+# This module is shared by multiple languages; use include blocker.
+if(__LINUX_COMPILER_INTEL_LLVM)
+  return()
+endif()
+set(__LINUX_COMPILER_INTEL_LLVM 1)
+
+if(NOT XIAR)
+  set(_intel_xiar_hints)
+  foreach(lang C CXX Fortran)
+    if(IS_ABSOLUTE "${CMAKE_${lang}_COMPILER}")
+      get_filename_component(_hint "${CMAKE_${lang}_COMPILER}" PATH)
+      list(APPEND _intel_xiar_hints ${_hint})
+    endif()
+  endforeach()
+  find_program(XIAR NAMES xiar HINTS ${_intel_xiar_hints})
+  mark_as_advanced(XIAR)
+endif()
+
+macro(__linux_compiler_intel_llvm lang)
+  set(CMAKE_${lang}_COMPILE_OPTIONS_PIC "-fPIC")
+  set(CMAKE_${lang}_COMPILE_OPTIONS_PIE "-fPIE")
+  set(_CMAKE_${lang}_PIE_MAY_BE_SUPPORTED_BY_LINKER NO)
+  set(_CMAKE_${lang}_PIE_MAY_BE_SUPPORTED_BY_LINKER YES)
+  set(CMAKE_${lang}_LINK_OPTIONS_PIE ${CMAKE_${lang}_COMPILE_OPTIONS_PIE} "-pie")
+  set(CMAKE_${lang}_LINK_OPTIONS_NO_PIE "-no-pie")
+  set(CMAKE_SHARED_LIBRARY_${lang}_FLAGS "-fPIC")
+  set(CMAKE_SHARED_LIBRARY_CREATE_${lang}_FLAGS "-shared")
+
+  # We pass this for historical reasons.  Projects may have
+  # executables that use dlopen but do not set ENABLE_EXPORTS.
+  set(CMAKE_SHARED_LIBRARY_LINK_${lang}_FLAGS "-rdynamic")
+
+  set(CMAKE_${lang}_LINKER_WRAPPER_FLAG "-Wl,")
+  set(CMAKE_${lang}_LINKER_WRAPPER_FLAG_SEP ",")
+
+  set(_CMAKE_${lang}_IPO_SUPPORTED_BY_CMAKE YES)
+
+  if(XIAR)
+    # INTERPROCEDURAL_OPTIMIZATION
+    set(CMAKE_${lang}_COMPILE_OPTIONS_IPO -ipo)
+    set(CMAKE_${lang}_CREATE_STATIC_LIBRARY_IPO
+      "${XIAR} cr <TARGET> <LINK_FLAGS> <OBJECTS> "
+      "${XIAR} -s <TARGET> ")
+    set(_CMAKE_${lang}_IPO_MAY_BE_SUPPORTED_BY_COMPILER YES)
+    set(_CMAKE_${lang}_IPO_LEGACY_BEHAVIOR YES)
+  else()
+    set(_CMAKE_${lang}_IPO_MAY_BE_SUPPORTED_BY_COMPILER NO)
+  endif()
+
+  set(CMAKE_${lang}_COMPILE_OPTIONS_VISIBILITY "-fvisibility=")
+endmacro()
diff --git a/Modules/Platform/Windows-IntelLLVM-ASM.cmake b/Modules/Platform/Windows-IntelLLVM-ASM.cmake
new file mode 100644
index 0000000..f355e49
--- /dev/null
+++ b/Modules/Platform/Windows-IntelLLVM-ASM.cmake
@@ -0,0 +1,2 @@
+include(Platform/Windows-IntelLLVM)
+__windows_compiler_intel(ASM)
diff --git a/Modules/Platform/Windows-IntelLLVM-C.cmake b/Modules/Platform/Windows-IntelLLVM-C.cmake
new file mode 100644
index 0000000..93c3364
--- /dev/null
+++ b/Modules/Platform/Windows-IntelLLVM-C.cmake
@@ -0,0 +1,2 @@
+include(Platform/Windows-IntelLLVM)
+__windows_compiler_intel(C)
diff --git a/Modules/Platform/Windows-IntelLLVM-CXX.cmake b/Modules/Platform/Windows-IntelLLVM-CXX.cmake
new file mode 100644
index 0000000..4667895
--- /dev/null
+++ b/Modules/Platform/Windows-IntelLLVM-CXX.cmake
@@ -0,0 +1,3 @@
+include(Platform/Windows-IntelLLVM)
+set(_COMPILE_CXX " /TP")
+__windows_compiler_intel(CXX)
diff --git a/Modules/Platform/Windows-IntelLLVM-Fortran.cmake b/Modules/Platform/Windows-IntelLLVM-Fortran.cmake
new file mode 100644
index 0000000..06d0a00
--- /dev/null
+++ b/Modules/Platform/Windows-IntelLLVM-Fortran.cmake
@@ -0,0 +1,44 @@
+include(Platform/Windows-IntelLLVM)
+set(CMAKE_BUILD_TYPE_INIT Debug)
+set(_COMPILE_Fortran " /fpp")
+set(CMAKE_Fortran_MODDIR_FLAG "-module:")
+set(CMAKE_Fortran_STANDARD_LIBRARIES_INIT "user32.lib")
+__windows_compiler_intel(Fortran)
+if(CMAKE_MSVC_RUNTIME_LIBRARY_DEFAULT)
+  set(_LIBSDLL "")
+  set(_DBGLIBS "")
+  set(_THREADS "")
+else()
+  set(_LIBSDLL " /libs:dll")
+  set(_DBGLIBS " /dbglibs")
+  set(_THREADS " /threads")
+endif()
+
+cmake_policy(GET CMP0092 _cmp0092)
+if(NOT _cmp0092 STREQUAL "NEW")
+  string(APPEND CMAKE_Fortran_FLAGS_INIT " /W1")
+endif()
+unset(_cmp0092)
+
+string(APPEND CMAKE_Fortran_FLAGS_INIT " /nologo /fpp${_LIBSDLL}${_THREADS}")
+string(APPEND CMAKE_Fortran_FLAGS_DEBUG_INIT " /Od /debug:full${_DBGLIBS}")
+string(APPEND CMAKE_Fortran_FLAGS_MINSIZEREL_INIT " /O1 /DNDEBUG")
+string(APPEND CMAKE_Fortran_FLAGS_RELEASE_INIT " /O2 /DNDEBUG")
+string(APPEND CMAKE_Fortran_FLAGS_RELWITHDEBINFO_INIT " /O2 /debug:full /DNDEBUG")
+unset(_LIBSDLL)
+unset(_DBGLIBS)
+unset(_THREADS)
+
+set(CMAKE_Fortran_COMPILE_OPTIONS_MSVC_RUNTIME_LIBRARY_MultiThreaded         -threads -libs:static)
+set(CMAKE_Fortran_COMPILE_OPTIONS_MSVC_RUNTIME_LIBRARY_MultiThreadedDLL      -threads -libs:dll)
+set(CMAKE_Fortran_COMPILE_OPTIONS_MSVC_RUNTIME_LIBRARY_MultiThreadedDebug    -threads -libs:static -dbglibs)
+set(CMAKE_Fortran_COMPILE_OPTIONS_MSVC_RUNTIME_LIBRARY_MultiThreadedDebugDLL -threads -libs:dll    -dbglibs)
+
+# Intel Fortran for Windows supports single-threaded RTL but it is
+# not implemented by the Visual Studio integration.
+if(NOT CMAKE_GENERATOR MATCHES "Visual Studio")
+  set(CMAKE_Fortran_COMPILE_OPTIONS_MSVC_RUNTIME_LIBRARY_SingleThreaded                 -libs:static)
+  set(CMAKE_Fortran_COMPILE_OPTIONS_MSVC_RUNTIME_LIBRARY_SingleThreadedDLL              -libs:dll)
+  set(CMAKE_Fortran_COMPILE_OPTIONS_MSVC_RUNTIME_LIBRARY_SingleThreadedDebug            -libs:static -dbglibs)
+  set(CMAKE_Fortran_COMPILE_OPTIONS_MSVC_RUNTIME_LIBRARY_SingleThreadedDebugDLL         -libs:dll    -dbglibs)
+endif()
diff --git a/Modules/Platform/Windows-IntelLLVM.cmake b/Modules/Platform/Windows-IntelLLVM.cmake
new file mode 100644
index 0000000..b9ea037
--- /dev/null
+++ b/Modules/Platform/Windows-IntelLLVM.cmake
@@ -0,0 +1,17 @@
+# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
+
+# This module is shared by multiple languages; use include blocker.
+if(__WINDOWS_INTEL)
+  return()
+endif()
+set(__WINDOWS_INTEL 1)
+
+include(Platform/Windows-MSVC)
+macro(__windows_compiler_intel lang)
+  __windows_compiler_msvc(${lang})
+
+  set(CMAKE_DEPFILE_FLAGS_${lang} "-QMMD -QMT <DEP_TARGET> -QMF <DEP_FILE>")
+  set(CMAKE_${lang}_DEPFILE_FORMAT gcc)
+endmacro()
diff --git a/Source/CMakeLists.txt b/Source/CMakeLists.txt
index dca94ee..b3d8369 100644
--- a/Source/CMakeLists.txt
+++ b/Source/CMakeLists.txt
@@ -46,6 +46,8 @@ if(NOT CMake_DEFAULT_RECURSION_LIMIT)
     set(CMake_DEFAULT_RECURSION_LIMIT 100)
   elseif(MINGW)
     set(CMake_DEFAULT_RECURSION_LIMIT 400)
+  elseif(WIN32 AND CMAKE_C_COMPILER_ID STREQUAL "IntelLLVM")
+    set(CMake_DEFAULT_RECURSION_LIMIT 600)
   else()
     set(CMake_DEFAULT_RECURSION_LIMIT 1000)
   endif()
diff --git a/Source/CursesDialog/form/CMakeLists.txt b/Source/CursesDialog/form/CMakeLists.txt
index 21c499e..8f26b9a 100644
--- a/Source/CursesDialog/form/CMakeLists.txt
+++ b/Source/CursesDialog/form/CMakeLists.txt
@@ -5,7 +5,7 @@ project(CMAKE_FORM)
 
 # Disable warnings to avoid changing 3rd party code.
 if(CMAKE_C_COMPILER_ID MATCHES
-    "^(GNU|Clang|AppleClang|XLClang|XL|VisualAge|SunPro|HP|Intel)$")
+    "^(GNU|Clang|AppleClang|XLClang|XL|VisualAge|SunPro|HP|Intel|IntelLLVM)$")
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -w")
 elseif(CMAKE_C_COMPILER_ID STREQUAL "PathScale")
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -woffall")
diff --git a/Tests/Assembler/CMakeLists.txt b/Tests/Assembler/CMakeLists.txt
index a574c4e..0a2c819 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 STREQUAL "Intel"  AND  UNIX)
+  if((CMAKE_C_COMPILER_ID MATCHES "^(GNU|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 "${CMAKE_C_FLAGS}")
     separate_arguments(C_FLAGS)
diff --git a/Tests/CMakeLists.txt b/Tests/CMakeLists.txt
index d28d89f..4ed902c 100644
--- a/Tests/CMakeLists.txt
+++ b/Tests/CMakeLists.txt
@@ -429,6 +429,10 @@ if(BUILD_TESTING)
         set(CMAKE_SKIP_VSGNUFortran TRUE)
       endif()
     endif()
+    if(CMAKE_Fortran_COMPILER_ID STREQUAL IntelLLVM)
+      message(STATUS "Skip VSGNUFortran for ifx until DLLEXPORT support is implemented")
+      set(CMAKE_SKIP_VSGNUFortran TRUE)
+    endif()
     if((CMAKE_C_COMPILER MATCHES lsb)
         AND (CMAKE_Fortran_COMPILER MATCHES ifort))
       message(STATUS "Skip VSGNUFortran for ifort and lsb compilers")
@@ -1948,7 +1952,7 @@ if(BUILD_TESTING)
     if(NOT CMAKE_C_COMPILER_ID STREQUAL "Clang" OR NOT "x${CMAKE_C_COMPILER_FRONTEND_VARIANT}" STREQUAL "xGNU")
       ADD_TEST_MACRO(ForceInclude foo)
     endif()
-    if(NOT CMAKE_C_COMPILER_ID STREQUAL "Clang")
+    if(NOT CMAKE_C_COMPILER_ID STREQUAL "Clang" AND NOT CMAKE_C_COMPILER_ID STREQUAL "IntelLLVM")
       ADD_TEST_MACRO(PrecompiledHeader foo)
     endif()
     set(MSVCRuntimeLibrary_BUILD_OPTIONS -DCMake_TEST_CUDA=${CMake_TEST_CUDA})
@@ -2014,12 +2018,19 @@ if(BUILD_TESTING)
         endif()
       endif()
 
-      # For the Watcom WMake generator, avoid the MFC test by default.
       if(CTEST_RUN_MFC)
+        # For the Watcom WMake generator, avoid the MFC test by default.
         if("${CMAKE_GENERATOR}" MATCHES "WMake")
           message(STATUS
             "using the Watcom WMake generator, avoiding MFC test")
           set(CTEST_RUN_MFC OFF)
+        elseif("${CMAKE_CXX_COMPILER_ID}" STREQUAL "IntelLLVM")
+          # clang-cl cannot deal with implicit dependencies in UTF16 files
+          # (see #18311).  IntelLLVM inherits this behavior from Clang.
+          # TODO: maybe clang should also skip the MFC test
+          message(STATUS
+            "using generator other than Visual Studio with clang-cl, avoiding MFC test")
+          set(CTEST_RUN_MFC OFF)
         endif()
       endif()
 
diff --git a/Tests/CTestCoverageCollectGCOV/test.cmake.in b/Tests/CTestCoverageCollectGCOV/test.cmake.in
index 1818888..a36f374 100644
--- a/Tests/CTestCoverageCollectGCOV/test.cmake.in
+++ b/Tests/CTestCoverageCollectGCOV/test.cmake.in
@@ -29,6 +29,20 @@ set(expected_out
   uncovered/uncovered2.cpp
 )
 
+# A symbolic link in the path can cause tar to put an equivalent, but not
+# minimal file name to some files in the tar file.  Convert paths to absolute
+# then back to relative to get them in canonical form (or maybe this is a bug
+# in how the tarball is generated?)
+function(to_relative_paths real_paths paths)
+  foreach(file ${paths})
+    file(REAL_PATH "${file}" real_path BASE_DIRECTORY "${CTEST_BINARY_DIRECTORY}")
+    file(RELATIVE_PATH relative_path "${CTEST_BINARY_DIRECTORY}" "${real_path}")
+    list(APPEND local_real_paths "${relative_path}")
+    message(DEBUG "${file} -> ${real_path} -> ${relative_path}")
+  endforeach()
+  set("${real_paths}" "${local_real_paths}" PARENT_SCOPE)
+endfunction()
+
 #------------------------------------------------------------------------------#
 # Test 1: with standard arguments
 #------------------------------------------------------------------------------#
@@ -50,6 +64,7 @@ execute_process(COMMAND
 )
 
 string(REPLACE "\n" ";" out "${out}")
+to_relative_paths(out "${out}")
 list(SORT out)
 
 if("${out}" STREQUAL "${expected_out}")
@@ -80,6 +95,7 @@ execute_process(COMMAND
 )
 
 string(REPLACE "\n" ";" out "${out}")
+to_relative_paths(out "${out}")
 list(SORT out)
 
 if("${out}" STREQUAL "${expected_out}")
@@ -110,6 +126,7 @@ execute_process(COMMAND
 )
 
 string(REPLACE "\n" ";" out "${out}")
+to_relative_paths(out "${out}")
 list(SORT out)
 
 if("${out}" STREQUAL "${expected_out}")
@@ -140,6 +157,7 @@ execute_process(COMMAND
 )
 
 string(REPLACE "\n" ";" out "${out}")
+to_relative_paths(out "${out}")
 list(SORT out)
 
 if("${out}" STREQUAL "${expected_out}")
@@ -170,6 +188,7 @@ execute_process(COMMAND
 )
 
 string(REPLACE "\n" ";" out "${out}")
+to_relative_paths(out "${out}")
 list(SORT out)
 
 if("${out}" STREQUAL "${expected_out}")
diff --git a/Tests/CTestUpdateCVS.cmake.in b/Tests/CTestUpdateCVS.cmake.in
index 5389bdf..8e0b611 100644
--- a/Tests/CTestUpdateCVS.cmake.in
+++ b/Tests/CTestUpdateCVS.cmake.in
@@ -17,21 +17,11 @@ message("Using CVS tools:")
 set(CVS "@CVS_EXECUTABLE@")
 message(" cvs = ${CVS}")
 
-set(REPO ${TOP}/repo)
-
-# The MSYS cvs tool interprets "c:/" as a "machine:" name for SSH.
-# Detect the MSYS cvs and convert the repo path to an MSYS path.
-if(WIN32)
-  if(EXISTS "${CVS}")
-    file(STRINGS "${CVS}" cvs_is_msys LIMIT_COUNT 1 REGEX "[Mm][Ss][Yy][Ss]")
-    if(cvs_is_msys)
-      message("  '${CVS}' is from MSYS (contains '${cvs_is_msys}')")
-      string(REGEX REPLACE "^([A-Za-z]):" "/\\1" REPO "${REPO}")
-    endif()
-  endif()
-endif()
+# Pre-pending :local: prevents cvs from trying to interpret Windows drive
+# letters, like "C:", as host names.
+set(REPO ":local:${TOP}/repo")
 
-set(CVSCMD ${CVS} -d${REPO})
+set(CVSCMD ${CVS} -d "${REPO}")
 
 # CVSNT requires an extra option to 'cvs init'.
 set(CVS_INIT_OPT)
diff --git a/Tests/CompileFeatures/CMakeLists.txt b/Tests/CompileFeatures/CMakeLists.txt
index 922e07f..cff98e3 100644
--- a/Tests/CompileFeatures/CMakeLists.txt
+++ b/Tests/CompileFeatures/CMakeLists.txt
@@ -4,9 +4,12 @@ cmake_policy(SET CMP0057 NEW)
 
 project(CompileFeatures)
 
+set(ext_C c)
+set(ext_CXX cpp)
+
 macro(run_test feature lang)
   if (${feature} IN_LIST CMAKE_${lang}_COMPILE_FEATURES)
-    add_library(test_${feature} OBJECT ${feature})
+    add_library(test_${feature} OBJECT ${feature}.${ext_${lang}})
     set_property(TARGET test_${feature}
       PROPERTY COMPILE_FEATURES "${feature}"
     )
@@ -15,7 +18,7 @@ macro(run_test feature lang)
   endif()
 endmacro()
 
-if(NOT CMAKE_C_COMPILER_ID MATCHES "^(Cray|PGI|NVHPC|XL|XLClang)$")
+if(NOT CMAKE_C_COMPILER_ID MATCHES "^(Cray|PGI|NVHPC|XL|XLClang|IntelLLVM)$")
   get_property(c_features GLOBAL PROPERTY CMAKE_C_KNOWN_FEATURES)
   list(FILTER c_features EXCLUDE REGEX "^c_std_[0-9][0-9]")
   foreach(feature ${c_features})
@@ -23,7 +26,7 @@ if(NOT CMAKE_C_COMPILER_ID MATCHES "^(Cray|PGI|NVHPC|XL|XLClang)$")
   endforeach()
 endif()
 
-if(NOT CMAKE_CXX_COMPILER_ID MATCHES "^(Cray|PGI|NVHPC|XL|XLClang)$")
+if(NOT CMAKE_CXX_COMPILER_ID MATCHES "^(Cray|PGI|NVHPC|XL|XLClang|IntelLLVM)$")
   get_property(cxx_features GLOBAL PROPERTY CMAKE_CXX_KNOWN_FEATURES)
   list(FILTER cxx_features EXCLUDE REGEX "^cxx_std_[0-9][0-9]")
   foreach(feature ${cxx_features})
diff --git a/Tests/ExternalProject/CMakeLists.txt b/Tests/ExternalProject/CMakeLists.txt
index 132abf4..59e3bcc 100644
--- a/Tests/ExternalProject/CMakeLists.txt
+++ b/Tests/ExternalProject/CMakeLists.txt
@@ -161,7 +161,7 @@ if(do_cvs_tests)
   #
   set(proj TutorialStep1-CVS-20090626)
   ExternalProject_Add(${proj}
-    CVS_REPOSITORY "${local_cvs_repo}"
+    CVS_REPOSITORY ":local:${local_cvs_repo}"
     CVS_MODULE "TutorialStep1"
     CVS_TAG "-D2009-06-26 16:50:00 UTC"
     UPDATE_COMMAND ""
@@ -176,7 +176,7 @@ if(do_cvs_tests)
   #
   set(proj TutorialStep1-CVS-testtag1)
   ExternalProject_Add(${proj}
-    CVS_REPOSITORY "${local_cvs_repo}"
+    CVS_REPOSITORY ":local:${local_cvs_repo}"
     CVS_MODULE "TutorialStep1"
     CVS_TAG -rtesttag1
     UPDATE_COMMAND ""
@@ -191,7 +191,7 @@ if(do_cvs_tests)
   #
   set(proj TutorialStep1-CVS-HEAD)
   ExternalProject_Add(${proj}
-    CVS_REPOSITORY "${local_cvs_repo}"
+    CVS_REPOSITORY ":local:${local_cvs_repo}"
     CVS_MODULE "TutorialStep1"
     CMAKE_GENERATOR "${CMAKE_GENERATOR}"
     CMAKE_ARGS -DCMAKE_INSTALL_PREFIX:PATH=<INSTALL_DIR>
diff --git a/Tests/Fortran/CMakeLists.txt b/Tests/Fortran/CMakeLists.txt
index 929fa4d..1868892 100644
--- a/Tests/Fortran/CMakeLists.txt
+++ b/Tests/Fortran/CMakeLists.txt
@@ -120,7 +120,7 @@ endfunction()
 # if the id's match or the compilers are compatible, then
 # call the test_fortran_c_interface_module function
 if("${CMAKE_Fortran_COMPILER_ID}:${CMAKE_C_COMPILER_ID}" MATCHES
-    "(Intel:MSVC|Absoft:GNU)"
+    "(Intel(LLVM)?:MSVC|Absoft:GNU)"
     OR ("${CMAKE_Fortran_COMPILER_ID}" STREQUAL "${CMAKE_C_COMPILER_ID}" ))
   test_fortran_c_interface_module()
 else()
diff --git a/Tests/Fortran/myc.c b/Tests/Fortran/myc.c
index efd9b68..1a4d5a4 100644
--- a/Tests/Fortran/myc.c
+++ b/Tests/Fortran/myc.c
@@ -1,6 +1,6 @@
 #include "foo.h"
-extern F_test_mod_sub(void);
-extern F_mysub(void);
+extern void F_test_mod_sub(void);
+extern void F_mysub(void);
 int myc(void)
 {
   F_mysub();
diff --git a/Tests/FortranOnly/CMakeLists.txt b/Tests/FortranOnly/CMakeLists.txt
index b40f05e..b5b5e56 100644
--- a/Tests/FortranOnly/CMakeLists.txt
+++ b/Tests/FortranOnly/CMakeLists.txt
@@ -111,7 +111,7 @@ endif()
 
 # Test that with Intel Fortran we always compile with preprocessor
 # defines even if splitting the preprocessing and compilation steps.
-if(CMAKE_Fortran_COMPILER_ID STREQUAL "Intel")
+if(CMAKE_Fortran_COMPILER_ID MATCHES "Intel")
   add_executable(IntelIfDef IntelIfDef.f)
   set_property(TARGET IntelIfDef PROPERTY Fortran_FORMAT FIXED)
   target_compile_definitions(IntelIfDef PRIVATE SOME_DEF)
@@ -152,7 +152,7 @@ if(test_pp_flags AND NOT CMAKE_Fortran_COMPILER_ID MATCHES "(Flang|NAG|PGI|NVHPC
   add_library(no_preprocess_source STATIC no_preprocess_source_upper.F)
   target_compile_options(no_preprocess_source PRIVATE -DINTEGER=nonsense)
   if(NOT CMAKE_Fortran_COMPILER_ID STREQUAL "Cray"
-      AND NOT "${CMAKE_Fortran_COMPILER_ID};${CMAKE_Fortran_SIMULATE_ID}" STREQUAL "Intel;MSVC")
+      AND NOT "${CMAKE_Fortran_COMPILER_ID};${CMAKE_Fortran_SIMULATE_ID}" MATCHES "Intel(LLVM)?;MSVC")
     target_sources(no_preprocess_target PRIVATE no_preprocess_target_fpp.fpp)
     target_sources(no_preprocess_source PRIVATE no_preprocess_source_fpp.fpp)
   endif()
diff --git a/Tests/MSVCRuntimeLibrary/Fortran/CMakeLists.txt b/Tests/MSVCRuntimeLibrary/Fortran/CMakeLists.txt
index 27838a4..41bd6f5 100644
--- a/Tests/MSVCRuntimeLibrary/Fortran/CMakeLists.txt
+++ b/Tests/MSVCRuntimeLibrary/Fortran/CMakeLists.txt
@@ -6,8 +6,9 @@ foreach(t MultiThreaded SingleThreaded)
   foreach(dbg "" Debug)
     foreach(dll "" DLL)
       set(var "CMAKE_Fortran_COMPILE_OPTIONS_MSVC_RUNTIME_LIBRARY_${t}${dbg}${dll}")
-      if(CMAKE_Fortran_COMPILER_ID STREQUAL "Intel")
-        # ifort does not actually define these, so inject them
+      if(CMAKE_Fortran_COMPILER_ID STREQUAL "Intel"
+        OR CMAKE_Fortran_COMPILER_ID STREQUAL "IntelLLVM")
+        # ifort and ifx do not actually define these, so inject them
         string(REPLACE "-threads" "-threads;-D_MT" "${var}" "${${var}}")
         string(REPLACE "-dbglibs" "-dbglibs;-D_DEBUG" "${var}" "${${var}}")
       elseif(CMAKE_Fortran_COMPILER_ID STREQUAL "Flang")
diff --git a/Tests/Module/WriteCompilerDetectionHeader/CMakeLists.txt b/Tests/Module/WriteCompilerDetectionHeader/CMakeLists.txt
index 7339222..0cf74bf 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)$")
+  if(NOT CMAKE_C_COMPILER_ID MATCHES "^(Cray|PGI|NVHPC|XL|XLClang|IntelLLVM)$")
     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)$")
+  if(NOT CMAKE_CXX_COMPILER_ID MATCHES "^(Cray|PGI|NVHPC|XL|XLClang|IntelLLVM)$")
     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/PDBDirectoryAndName/CMakeLists.txt b/Tests/PDBDirectoryAndName/CMakeLists.txt
index 95aa351..5aa2459 100644
--- a/Tests/PDBDirectoryAndName/CMakeLists.txt
+++ b/Tests/PDBDirectoryAndName/CMakeLists.txt
@@ -9,8 +9,9 @@ endif()
 
 # Intel 11.1 does not support /Fd but Intel 14.0 does.
 # TODO: Did a version in between these add it?
-if(CMAKE_C_COMPILER_ID STREQUAL Intel AND
-   CMAKE_C_COMPILER_VERSION VERSION_LESS 14.0)
+if((CMAKE_C_COMPILER_ID STREQUAL Intel AND
+    CMAKE_C_COMPILER_VERSION VERSION_LESS 14.0) OR
+   CMAKE_C_COMPILER_ID STREQUAL "IntelLLVM")
   set(NO_COMPILE_PDB 1)
 endif()
 
diff --git a/Tests/Preprocess/CMakeLists.txt b/Tests/Preprocess/CMakeLists.txt
index bce1b3f..bf2af64 100644
--- a/Tests/Preprocess/CMakeLists.txt
+++ b/Tests/Preprocess/CMakeLists.txt
@@ -147,8 +147,13 @@ endif()
 #  - NMake is okay with just \\\"
 #  - The XL compiler does not re-escape \\\" when launching an
 #    internal tool to do preprocessing .
+#  - The IntelLLVM C and C++ compiler drivers do not re-escape the \\\" when
+#    launching the underlying compiler. FIXME: this bug is expected to be fixed
+#    in a future release.
 if((PP_NMAKE OR PP_UMAKE) AND
-    NOT CMAKE_C_COMPILER_ID STREQUAL "XL")
+    NOT CMAKE_C_COMPILER_ID STREQUAL "XL" AND
+    NOT CMAKE_C_COMPILER_ID STREQUAL "IntelLLVM" AND
+    NOT CMAKE_CXX_COMPILER_ID STREQUAL "IntelLLVM")
   string(APPEND STRING_EXTRA "\\\"")
 endif()
 
diff --git a/Tests/RunCMake/CPack/VerifyResult.cmake b/Tests/RunCMake/CPack/VerifyResult.cmake
index 345b37f..0ab545a 100644
--- a/Tests/RunCMake/CPack/VerifyResult.cmake
+++ b/Tests/RunCMake/CPack/VerifyResult.cmake
@@ -79,6 +79,11 @@ if(NOT EXPECTED_FILES_COUNT EQUAL 0)
           "which does not match:${msg_expected}\n"
           "${output_error_message}")
       endif()
+    elseif(foundFilescount_ EQUAL 0)
+      message(FATAL_ERROR
+        "Found no files for file No. '${file_no_}'!"
+        " Globbing expression: '${EXPECTED_FILE_${file_no_}}'"
+        "${output_error_message}")
     else()
       message(FATAL_ERROR
         "Found more than one file for file No. '${file_no_}'!"
diff --git a/Tests/RunCMake/CPack/tests/DEBUGINFO/test.cmake b/Tests/RunCMake/CPack/tests/DEBUGINFO/test.cmake
index 04b44f6..9ff1f8a 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 "^(PGI|NVHPC)$")
+if(CMAKE_CXX_COMPILER_ID MATCHES "^(IntelLLVM|PGI|NVHPC)$")
   string(APPEND CMAKE_EXE_LINKER_FLAGS "-Wl,--build-id")
   string(APPEND CMAKE_SHARED_LINKER_FLAGS "-Wl,--build-id")
 endif()
diff --git a/Tests/RunCMake/DependencyGraph/RunCMakeTest.cmake b/Tests/RunCMake/DependencyGraph/RunCMakeTest.cmake
index cb0d541..891e138 100644
--- a/Tests/RunCMake/DependencyGraph/RunCMakeTest.cmake
+++ b/Tests/RunCMake/DependencyGraph/RunCMakeTest.cmake
@@ -10,7 +10,8 @@ function(check_files dir)
   set(actual)
   foreach(i IN LISTS glob)
     if(NOT i MATCHES "(\\.manifest$)|(\\.exp$)|(\\.tds$)")
-      list(APPEND actual ${i})
+      get_filename_component(real_path ${i} REALPATH)
+      list(APPEND actual ${real_path})
     endif()
   endforeach()
   list(REMOVE_DUPLICATES actual)
diff --git a/Tests/RunCMake/FileAPI/codemodel-v2-check.py b/Tests/RunCMake/FileAPI/codemodel-v2-check.py
index c66757f..df2410a 100644
--- a/Tests/RunCMake/FileAPI/codemodel-v2-check.py
+++ b/Tests/RunCMake/FileAPI/codemodel-v2-check.py
@@ -608,7 +608,7 @@ def gen_check_targets(c, g, inSource):
         read_codemodel_json_data("targets/generated_exe.json"),
     ]
 
-    if cxx_compiler_id in ['Clang', 'AppleClang', 'GNU', 'Intel', 'MSVC', 'Embarcadero'] and g["name"] != "Xcode":
+    if cxx_compiler_id in ['Clang', 'AppleClang', '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/GenerateExportHeader/GEH.cmake b/Tests/RunCMake/GenerateExportHeader/GEH.cmake
index ae9a84c..431d1ce 100644
--- a/Tests/RunCMake/GenerateExportHeader/GEH.cmake
+++ b/Tests/RunCMake/GenerateExportHeader/GEH.cmake
@@ -103,7 +103,7 @@ add_executable(GenerateExportHeader exportheader_test.cpp)
 
 target_link_libraries(GenerateExportHeader ${link_libraries})
 if (WIN32 OR CYGWIN)
-  if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND
+  if((CMAKE_CXX_COMPILER_ID STREQUAL "Clang" OR CMAKE_CXX_COMPILER_ID STREQUAL "IntelLLVM") AND
     CMAKE_CXX_SIMULATE_ID STREQUAL "MSVC")
     set(_platform Win32-Clang)
   elseif(MSVC AND COMPILER_HAS_DEPRECATED)
diff --git a/Utilities/cmbzip2/CMakeLists.txt b/Utilities/cmbzip2/CMakeLists.txt
index cb4a038..9b53b0f 100644
--- a/Utilities/cmbzip2/CMakeLists.txt
+++ b/Utilities/cmbzip2/CMakeLists.txt
@@ -2,7 +2,7 @@ project(bzip2)
 
 # Disable warnings to avoid changing 3rd party code.
 if(CMAKE_C_COMPILER_ID MATCHES
-    "^(GNU|Clang|AppleClang|XLClang|XL|VisualAge|SunPro|HP|Intel)$")
+    "^(GNU|Clang|AppleClang|XLClang|XL|VisualAge|SunPro|HP|Intel|IntelLLVM)$")
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -w")
 elseif(CMAKE_C_COMPILER_ID STREQUAL "PathScale")
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -woffall")
diff --git a/Utilities/cmcurl/CMakeLists.txt b/Utilities/cmcurl/CMakeLists.txt
index ecdf3af..327c829 100644
--- a/Utilities/cmcurl/CMakeLists.txt
+++ b/Utilities/cmcurl/CMakeLists.txt
@@ -95,7 +95,7 @@ endif(APPLE)
 
 # Disable warnings to avoid changing 3rd party code.
 if(CMAKE_C_COMPILER_ID MATCHES
-    "^(GNU|Clang|AppleClang|XLClang|XL|VisualAge|SunPro|HP|Intel)$")
+    "^(GNU|Clang|AppleClang|XLClang|XL|VisualAge|SunPro|HP|Intel|IntelLLVM)$")
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -w")
 elseif(CMAKE_C_COMPILER_ID STREQUAL "PathScale")
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -woffall")
diff --git a/Utilities/cmexpat/CMakeLists.txt b/Utilities/cmexpat/CMakeLists.txt
index cf31556..b8dc4e8 100644
--- a/Utilities/cmexpat/CMakeLists.txt
+++ b/Utilities/cmexpat/CMakeLists.txt
@@ -1,6 +1,6 @@
 # Disable warnings to avoid changing 3rd party code.
 IF(CMAKE_C_COMPILER_ID MATCHES
-    "^(GNU|Clang|AppleClang|XLClang|XL|VisualAge|SunPro|HP|Intel)$")
+    "^(GNU|Clang|AppleClang|XLClang|XL|VisualAge|SunPro|HP|Intel|IntelLLVM)$")
   SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -w")
 ELSEIF(CMAKE_C_COMPILER_ID STREQUAL "PathScale")
   SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -woffall")
diff --git a/Utilities/cmjsoncpp/CMakeLists.txt b/Utilities/cmjsoncpp/CMakeLists.txt
index 764be8d..74e9988 100644
--- a/Utilities/cmjsoncpp/CMakeLists.txt
+++ b/Utilities/cmjsoncpp/CMakeLists.txt
@@ -2,7 +2,7 @@ project(JsonCpp CXX)
 
 # Disable warnings to avoid changing 3rd party code.
 if(CMAKE_CXX_COMPILER_ID MATCHES
-    "^(GNU|Clang|AppleClang|XLClang|XL|VisualAge|SunPro|HP|Intel)$")
+    "^(GNU|Clang|AppleClang|XLClang|XL|VisualAge|SunPro|HP|Intel|IntelLLVM)$")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -w")
 elseif(CMAKE_CXX_COMPILER_ID STREQUAL "PathScale")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -woffall")
diff --git a/Utilities/cmlibarchive/CMakeLists.txt b/Utilities/cmlibarchive/CMakeLists.txt
index 6d6c1fb..689d98a 100644
--- a/Utilities/cmlibarchive/CMakeLists.txt
+++ b/Utilities/cmlibarchive/CMakeLists.txt
@@ -94,7 +94,7 @@ SET(CMAKE_REQUIRED_FLAGS)
 
 # Disable warnings to avoid changing 3rd party code.
 IF(CMAKE_C_COMPILER_ID MATCHES
-    "^(GNU|Clang|AppleClang|XLClang|XL|VisualAge|SunPro|HP|Intel)$")
+    "^(GNU|Clang|AppleClang|XLClang|XL|VisualAge|SunPro|HP|Intel|IntelLLVM)$")
   SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -w")
 ELSEIF(CMAKE_C_COMPILER_ID STREQUAL "PathScale")
   SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -woffall")
diff --git a/Utilities/cmliblzma/CMakeLists.txt b/Utilities/cmliblzma/CMakeLists.txt
index 6b6fae6..32a14dc 100644
--- a/Utilities/cmliblzma/CMakeLists.txt
+++ b/Utilities/cmliblzma/CMakeLists.txt
@@ -148,7 +148,7 @@ INCLUDE_DIRECTORIES(
 
 # Disable warnings to avoid changing 3rd party code.
 IF(CMAKE_C_COMPILER_ID MATCHES
-    "^(GNU|Clang|AppleClang|XLClang|XL|VisualAge|SunPro|HP|Intel)$")
+    "^(GNU|Clang|AppleClang|XLClang|XL|VisualAge|SunPro|HP|Intel|IntelLLVM)$")
   SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -w")
 ELSEIF(CMAKE_C_COMPILER_ID STREQUAL "PathScale")
   SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -woffall")
diff --git a/Utilities/cmlibrhash/CMakeLists.txt b/Utilities/cmlibrhash/CMakeLists.txt
index 1b025fc..37e2399 100644
--- a/Utilities/cmlibrhash/CMakeLists.txt
+++ b/Utilities/cmlibrhash/CMakeLists.txt
@@ -2,7 +2,7 @@ project(librhash C)
 
 # Disable warnings to avoid changing 3rd party code.
 if(CMAKE_C_COMPILER_ID MATCHES
-    "^(GNU|Clang|AppleClang|XLClang|XL|VisualAge|SunPro|HP|Intel)$")
+    "^(GNU|Clang|AppleClang|XLClang|XL|VisualAge|SunPro|HP|Intel|IntelLLVM)$")
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -w")
 elseif(CMAKE_C_COMPILER_ID STREQUAL "PathScale")
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -woffall")
diff --git a/Utilities/cmlibuv/CMakeLists.txt b/Utilities/cmlibuv/CMakeLists.txt
index 92d2411..f8b47af 100644
--- a/Utilities/cmlibuv/CMakeLists.txt
+++ b/Utilities/cmlibuv/CMakeLists.txt
@@ -2,7 +2,7 @@ project(libuv C)
 
 # Disable warnings to avoid changing 3rd party code.
 if(CMAKE_C_COMPILER_ID MATCHES
-    "^(GNU|Clang|AppleClang|XLClang|XL|VisualAge|SunPro|HP|Intel)$")
+    "^(GNU|Clang|AppleClang|XLClang|XL|VisualAge|SunPro|HP|Intel|IntelLLVM)$")
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -w")
 elseif(CMAKE_C_COMPILER_ID STREQUAL "PathScale")
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -woffall")
diff --git a/Utilities/cmnghttp2/CMakeLists.txt b/Utilities/cmnghttp2/CMakeLists.txt
index 3a11ace..17cc6dd 100644
--- a/Utilities/cmnghttp2/CMakeLists.txt
+++ b/Utilities/cmnghttp2/CMakeLists.txt
@@ -1,6 +1,6 @@
 # Disable warnings to avoid changing 3rd party code.
 if(CMAKE_C_COMPILER_ID MATCHES
-    "^(GNU|Clang|AppleClang|XLClang|XL|VisualAge|SunPro|HP|Intel)$")
+    "^(GNU|Clang|AppleClang|XLClang|XL|VisualAge|SunPro|HP|Intel|IntelLLVM)$")
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -w")
 elseif(CMAKE_C_COMPILER_ID STREQUAL "PathScale")
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -woffall")
diff --git a/Utilities/cmzlib/CMakeLists.txt b/Utilities/cmzlib/CMakeLists.txt
index 0584c55..d266af9 100644
--- a/Utilities/cmzlib/CMakeLists.txt
+++ b/Utilities/cmzlib/CMakeLists.txt
@@ -2,7 +2,7 @@ PROJECT(CMZLIB)
 
 # Disable warnings to avoid changing 3rd party code.
 if(CMAKE_C_COMPILER_ID MATCHES
-    "^(GNU|Clang|AppleClang|XLClang|XL|VisualAge|SunPro|HP|Intel)$")
+    "^(GNU|Clang|AppleClang|XLClang|XL|VisualAge|SunPro|HP|Intel|IntelLLVM)$")
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -w")
 elseif(CMAKE_C_COMPILER_ID STREQUAL "PathScale")
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -woffall")
diff --git a/Utilities/cmzstd/CMakeLists.txt b/Utilities/cmzstd/CMakeLists.txt
index 4f4f91f..323151c 100644
--- a/Utilities/cmzstd/CMakeLists.txt
+++ b/Utilities/cmzstd/CMakeLists.txt
@@ -2,7 +2,7 @@ project(zstd C)
 
 # Disable warnings to avoid changing 3rd party code.
 if(CMAKE_C_COMPILER_ID MATCHES
-    "^(GNU|Clang|AppleClang|XLClang|XL|VisualAge|SunPro|HP|Intel)$")
+    "^(GNU|Clang|AppleClang|XLClang|XL|VisualAge|SunPro|HP|Intel|IntelLLVM)$")
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -w")
 elseif(CMAKE_C_COMPILER_ID STREQUAL "PathScale")
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -woffall")