include(CheckCXXCompilerFlag)
include(CheckCXXSourceCompiles)

# Check for oneAPI compiler (some older CMake versions detect as Clang)
if (CMAKE_C_COMPILER_ID STREQUAL "Clang")
  check_cxx_source_compiles("#if (defined(__INTEL_CLANG_COMPILER) || defined(__INTEL_LLVM_COMPILER))
                             int main() { return 0; }
                             #else
                             not oneAPI
                             #endif" OPENMP_HAVE_ONEAPI_COMPILER)
  if (OPENMP_HAVE_ONEAPI_COMPILER)
    # According to CMake documentation, the compiler id should
    # be IntelLLVM when detected oneAPI
    set(CMAKE_C_COMPILER_ID "IntelLLVM")
    set(CMAKE_CXX_COMPILER_ID "IntelLLVM")
  endif()
endif()

check_cxx_compiler_flag(-Wall OPENMP_HAVE_WALL_FLAG)
check_cxx_compiler_flag(-Werror OPENMP_HAVE_WERROR_FLAG)
check_cxx_compiler_flag(-fcolor-diagnostics OPENMP_HAVE_COLOR_DIAGNOSTICS)

# Additional warnings that are not enabled by -Wall.
check_cxx_compiler_flag(-Wcast-qual OPENMP_HAVE_WCAST_QUAL_FLAG)
check_cxx_compiler_flag(-Wformat-pedantic OPENMP_HAVE_WFORMAT_PEDANTIC_FLAG)
check_cxx_compiler_flag(-Wimplicit-fallthrough OPENMP_HAVE_WIMPLICIT_FALLTHROUGH_FLAG)
check_cxx_compiler_flag(-Wsign-compare OPENMP_HAVE_WSIGN_COMPARE_FLAG)

# Warnings that we want to disable because they are too verbose or fragile.

# GCC silently accepts any -Wno-<foo> option, but warns about those options
# being unrecognized only if the compilation triggers other warnings to be
# printed. Therefore, check for whether the compiler supports options in the
# form -W<foo>, and if supported, add the corresponding -Wno-<foo> option.

check_cxx_compiler_flag(-Wextra OPENMP_HAVE_WEXTRA_FLAG)
check_cxx_compiler_flag(-Wpedantic OPENMP_HAVE_WPEDANTIC_FLAG)
check_cxx_compiler_flag(-Wmaybe-uninitialized OPENMP_HAVE_WMAYBE_UNINITIALIZED_FLAG)

# Additional flags for optimizing created libraries.

check_cxx_compiler_flag(-fno-semantic-interposition OPENMP_HAVE_NO_SEMANTIC_INTERPOSITION)
check_cxx_compiler_flag(-ffunction-section OPENMP_HAVE_FUNCTION_SECTIONS)
check_cxx_compiler_flag(-fdata-sections OPENMP_HAVE_DATA_SECTIONS)