if (NOT FAT_RUNTIME)
    if (BUILD_SVE2_BITPERM)
        message (STATUS "SVE2_BITPERM implies SVE2, enabling BUILD_SVE2")
        set(BUILD_SVE2 ON)
    endif ()
    if (BUILD_SVE2)
        message (STATUS "SVE2 implies SVE, enabling BUILD_SVE")
        set(BUILD_SVE ON)
    endif ()
endif ()

if (ARCH_AARCH64)
    if (NOT FAT_RUNTIME)
        if (BUILD_SVE2_BITPERM AND NOT SVE2_BITPERM_FOUND)
            set(GNUCC_ARCH "${GNUCC_ARCH}+sve2-bitperm")
        elseif (BUILD_SVE2 AND NOT SVE2_FOUND)
            set(GNUCC_ARCH "${GNUCC_ARCH}+sve2")
        elseif (BUILD_SVE AND NOT SVE_FOUND)
            set(GNUCC_ARCH "${GNUCC_ARCH}+sve")
        endif ()
    else()
        set(ARCH_C_FLAGS "")
        set(ARCH_CXX_FLAGS "")
    endif()
endif(ARCH_AARCH64)

CHECK_INCLUDE_FILE_CXX(arm_neon.h HAVE_C_ARM_NEON_H)
if (BUILD_SVE OR BUILD_SVE2 OR BUILD_SVE2_BITPERM OR FAT_RUNTIME)
  if (CMAKE_COMPILER_IS_CLANG)
    set(CMAKE_REQUIRED_FLAGS "-${ARCH_FLAG}=armv8-a+sve")
  else()
    set(CMAKE_REQUIRED_FLAGS ${ARCH_CXX_FLAGS})
  endif()
  CHECK_INCLUDE_FILE_CXX(arm_sve.h HAVE_C_ARM_SVE_H)
  if (NOT HAVE_C_ARM_SVE_H)
    message(FATAL_ERROR "arm_sve.h is required to build for SVE.")
  endif()
endif()

if (HAVE_C_EC_H)
    set (INTRIN_INC_H "altivec.h")
else()
    message (FATAL_ERROR "No intrinsics header found for VSX")
endif ()

if (ARCH_ARM32 OR ARCH_AARCH64)
    CHECK_C_SOURCE_COMPILES("#include <${INTRIN_INC_H}>
int main() {
    int32x4_t a = vdupq_n_s32(1);
    (void)a;
}" HAVE_NEON)
endif ()

set(PREV_FLAGS "${CMAKE_C_FLAGS}")
if (BUILD_SVE2_BITPERM)
    set(CMAKE_C_FLAGS "-march=${GNUCC_ARCH} ${CMAKE_C_FLAGS}")
    CHECK_C_SOURCE_COMPILES("#include <arm_sve.h>
    int main() {
        svuint8_t a = svbext(svdup_u8(1), svdup_u8(2));
        (void)a;
    }" HAVE_SVE2_BITPERM)
	if (HAVE_SVE2_BITPERM AND NOT FAT_RUNTIME)
            add_definitions(-DHAVE_SVE2_BITPERM)
        endif ()
    endif()
    if (BUILD_SVE2)
        set(CMAKE_C_FLAGS "-march=${GNUCC_ARCH} ${CMAKE_C_FLAGS}")
        CHECK_C_SOURCE_COMPILES("#include <arm_sve.h>
        int main() {
            svuint8_t a = svbsl(svdup_u8(1), svdup_u8(2), svdup_u8(3));
            (void)a;
        }" HAVE_SVE2)
    endif()
    if ((HAVE_SVE2 OR HAVE_SVE2_BITPERM) AND NOT FAT_RUNTIME)
        add_definitions(-DHAVE_SVE2)
    endif ()
    if (BUILD_SVE)
        set(CMAKE_C_FLAGS "-march=${GNUCC_ARCH} ${CMAKE_C_FLAGS}")
        CHECK_C_SOURCE_COMPILES("#include <arm_sve.h>
        int main() {
            svuint8_t a = svdup_u8(1);
            (void)a;
        }" HAVE_SVE)
    endif ()
    if ((HAVE_SVE OR HAVE_SVE2 OR HAVE_SVE2_BITPERM) AND NOT FAT_RUNTIME)
        add_definitions(-DHAVE_SVE)
    endif ()
    set(CMAKE_C_FLAGS "${PREV_FLAGS}")
endif()

if (FAT_RUNTIME)
    if ((ARCH_IA32 OR ARCH_X86_64) AND NOT HAVE_SSE42)
        message(FATAL_ERROR "SSE4.2 support required to build fat runtime")
    endif ()
    if ((ARCH_IA32 OR ARCH_X86_64) AND BUILD_AVX2 AND NOT HAVE_AVX2)
        message(FATAL_ERROR "AVX2 support required to build fat runtime")
    endif ()
    if ((ARCH_IA32 OR ARCH_X86_64) AND BUILD_AVX512 AND NOT HAVE_AVX512)
        message(FATAL_ERROR "AVX512 support requested but not supported")
    endif ()
    if ((ARCH_IA32 OR ARCH_X86_64) AND BUILD_AVX512VBMI AND NOT HAVE_AVX512VBMI)
        message(FATAL_ERROR "AVX512VBMI support requested but not supported")
    endif ()
else (NOT FAT_RUNTIME)
    if (ARCH_AARCH64 AND NOT BUILD_SVE)
        message(STATUS "Building without SVE support")
    endif ()
    if (ARCH_AARCH64 AND NOT BUILD_SVE2)
        message(STATUS "Building without SVE2 support")
    endif ()
    if ((ARCH_ARM32 OR ARCH_AARCH64) AND NOT HAVE_NEON)
        message(FATAL_ERROR "Neon/ASIMD support required for Arm support")
    endif ()
endif ()

    string(FIND "${GNUCC_ARCH}" "sve" POS_SVE)
    string(FIND "${GNUCC_ARCH}" "sve2" POS_SVE2)
    string(FIND "${GNUCC_ARCH}" "sve2-bitperm" POS_SVE2_BITPERM)
    if(NOT POS_SVE2_BITPERM EQUAL 0)
        set(SVE2_BITPERM_FOUND 1)
        set(SVE2_FOUND 1)
        set(SVE_FOUND 1)
    elseif(NOT POS_SVE2 EQUAL 0)
        set(SVE2_FOUND 1)
        set(SVE_FOUND 1)
    elseif (NOT POS_SVE EQUAL 0)
        set(SVE_FOUND 1)
        set(SVE2_BITPERM_FOUND 1)
    endif()