CMake module that detect SSE support

FindSSE.cmake

# Check if SSE instructions are available on the machine where 
# the project is compiled.

MACRO (FindSSE)

IF(CMAKE_SYSTEM_NAME MATCHES "Linux")
   EXEC_PROGRAM(cat ARGS "/proc/cpuinfo" OUTPUT_VARIABLE CPUINFO)

   STRING(REGEX REPLACE "^.*(sse2).*$" "¥¥1" SSE_THERE ${CPUINFO})
   STRING(COMPARE EQUAL "sse2" "${SSE_THERE}" SSE2_TRUE)
   IF (SSE2_TRUE)
      set(SSE2_FOUND true CACHE BOOL "SSE2 available on host")
   ELSE (SSE2_TRUE)
      set(SSE2_FOUND false CACHE BOOL "SSE2 available on host")
   ENDIF (SSE2_TRUE)

   # /proc/cpuinfo apparently omits sse3 :(
   STRING(REGEX REPLACE "^.*[^s](sse3).*$" "¥¥1" SSE_THERE ${CPUINFO})
   STRING(COMPARE EQUAL "sse3" "${SSE_THERE}" SSE3_TRUE)
   IF (NOT SSE3_TRUE)
      STRING(REGEX REPLACE "^.*(T2300).*$" "¥¥1" SSE_THERE ${CPUINFO})
      STRING(COMPARE EQUAL "T2300" "${SSE_THERE}" SSE3_TRUE)
   ENDIF (NOT SSE3_TRUE)

   STRING(REGEX REPLACE "^.*(ssse3).*$" "¥¥1" SSE_THERE ${CPUINFO})
   STRING(COMPARE EQUAL "ssse3" "${SSE_THERE}" SSSE3_TRUE)
   IF (SSE3_TRUE OR SSSE3_TRUE)
      set(SSE3_FOUND true CACHE BOOL "SSE3 available on host")
   ELSE (SSE3_TRUE OR SSSE3_TRUE)
      set(SSE3_FOUND false CACHE BOOL "SSE3 available on host")
   ENDIF (SSE3_TRUE OR SSSE3_TRUE)
   IF (SSSE3_TRUE)
      set(SSSE3_FOUND true CACHE BOOL "SSSE3 available on host")
   ELSE (SSSE3_TRUE)
      set(SSSE3_FOUND false CACHE BOOL "SSSE3 available on host")
   ENDIF (SSSE3_TRUE)

   STRING(REGEX REPLACE "^.*(sse4_1).*$" "¥¥1" SSE_THERE ${CPUINFO})
   STRING(COMPARE EQUAL "sse4_1" "${SSE_THERE}" SSE41_TRUE)
   IF (SSE41_TRUE)
      set(SSE4_1_FOUND true CACHE BOOL "SSE4.1 available on host")
   ELSE (SSE41_TRUE)
      set(SSE4_1_FOUND false CACHE BOOL "SSE4.1 available on host")
   ENDIF (SSE41_TRUE)

   STRING(REGEX REPLACE "^.*(sse4_2).*$" "¥¥1" SSE_THERE ${CPUINFO})
   STRING(COMPARE EQUAL "sse4_2" "${SSE_THERE}" SSE42_TRUE)
   IF (SSE42_TRUE)
      set(SSE4_2_FOUND true CACHE BOOL "SSE4.2 available on host")
   ELSE (SSE42_TRUE)
      set(SSE4_2_FOUND false CACHE BOOL "SSE4.2 available on host")
   ENDIF (SSE42_TRUE)

ELSEIF(CMAKE_SYSTEM_NAME MATCHES "Darwin")
   EXEC_PROGRAM("/usr/sbin/sysctl -n machdep.cpu.features" OUTPUT_VARIABLE
      CPUINFO)

   STRING(REGEX REPLACE "^.*[^S](SSE2).*$" "¥¥1" SSE_THERE ${CPUINFO})
   STRING(COMPARE EQUAL "SSE2" "${SSE_THERE}" SSE2_TRUE)
   IF (SSE2_TRUE)
      set(SSE2_FOUND true CACHE BOOL "SSE2 available on host")
   ELSE (SSE2_TRUE)
      set(SSE2_FOUND false CACHE BOOL "SSE2 available on host")
   ENDIF (SSE2_TRUE)

   STRING(REGEX REPLACE "^.*[^S](SSE3).*$" "¥¥1" SSE_THERE ${CPUINFO})
   STRING(COMPARE EQUAL "SSE3" "${SSE_THERE}" SSE3_TRUE)
   IF (SSE3_TRUE)
      set(SSE3_FOUND true CACHE BOOL "SSE3 available on host")
   ELSE (SSE3_TRUE)
      set(SSE3_FOUND false CACHE BOOL "SSE3 available on host")
   ENDIF (SSE3_TRUE)

   STRING(REGEX REPLACE "^.*(SSSE3).*$" "¥¥1" SSE_THERE ${CPUINFO})
   STRING(COMPARE EQUAL "SSSE3" "${SSE_THERE}" SSSE3_TRUE)
   IF (SSSE3_TRUE)
      set(SSSE3_FOUND true CACHE BOOL "SSSE3 available on host")
   ELSE (SSSE3_TRUE)
      set(SSSE3_FOUND false CACHE BOOL "SSSE3 available on host")
   ENDIF (SSSE3_TRUE)

   STRING(REGEX REPLACE "^.*(SSE4.1).*$" "¥¥1" SSE_THERE ${CPUINFO})
   STRING(COMPARE EQUAL "SSE4.1" "${SSE_THERE}" SSE41_TRUE)
   IF (SSE41_TRUE)
      set(SSE4_1_FOUND true CACHE BOOL "SSE4.1 available on host")
   ELSE (SSE41_TRUE)
      set(SSE4_1_FOUND false CACHE BOOL "SSE4.1 available on host")
   ENDIF (SSE41_TRUE)

   STRING(REGEX REPLACE "^.*(SSE4.2).*$" "¥¥1" SSE_THERE ${CPUINFO})
   STRING(COMPARE EQUAL "SSE4.2" "${SSE_THERE}" SSE42_TRUE)
   IF (SSE42_TRUE)
      set(SSE4_2_FOUND true CACHE BOOL "SSE4.2 available on host")
   ELSE (SSE42_TRUE)
      set(SSE4_2_FOUND false CACHE BOOL "SSE4.2 available on host")
   ENDIF (SSE42_TRUE)

ELSEIF(CMAKE_SYSTEM_NAME MATCHES "Windows")
   # TODO
   set(SSE2_FOUND   true  CACHE BOOL "SSE2 available on host")
   set(SSE3_FOUND   false CACHE BOOL "SSE3 available on host")
   set(SSSE3_FOUND  false CACHE BOOL "SSSE3 available on host")
   set(SSE4_1_FOUND false CACHE BOOL "SSE4.1 available on host")
   set(SSE4_2_FOUND false CACHE BOOL "SSE4.2 available on host")
ELSE(CMAKE_SYSTEM_NAME MATCHES "Linux")
   set(SSE2_FOUND   true  CACHE BOOL "SSE2 available on host")
   set(SSE3_FOUND   false CACHE BOOL "SSE3 available on host")
   set(SSSE3_FOUND  false CACHE BOOL "SSSE3 available on host")
   set(SSE4_1_FOUND false CACHE BOOL "SSE4.1 available on host")
   set(SSE4_2_FOUND false CACHE BOOL "SSE4.2 available on host")
ENDIF(CMAKE_SYSTEM_NAME MATCHES "Linux")

IF(CMAKE_COMPILER_IS_GNUCXX)
    EXECUTE_PROCESS(COMMAND ${CMAKE_CXX_COMPILER} -dumpversion OUTPUT_VARIABLE GCC_VERSION)
    IF(GCC_VERSION VERSION_LESS 4.2)
        set(SSE4_1_FOUND false CACHE BOOL "SSE4.1 available on host" FORCE)
        set(SSE4_2_FOUND false CACHE BOOL "SSE4.2 available on host" FORCE)
    ENDIF()
ENDIF(CMAKE_COMPILER_IS_GNUCXX)

if(NOT SSE2_FOUND)
      MESSAGE(STATUS "Could not find support for SSE2 on this machine.")
endif(NOT SSE2_FOUND)
if(NOT SSE3_FOUND)
      MESSAGE(STATUS "Could not find support for SSE3 on this machine.")
endif(NOT SSE3_FOUND)
if(NOT SSSE3_FOUND)
      MESSAGE(STATUS "Could not find support for SSSE3 on this machine.")
endif(NOT SSSE3_FOUND)
if(NOT SSE4_1_FOUND)
      MESSAGE(STATUS "Could not find support for SSE4.1 on this machine.")
endif(NOT SSE4_1_FOUND)
if(NOT SSE4_2_FOUND)
      MESSAGE(STATUS "Could not find support for SSE4.2 on this machine.")
endif(NOT SSE4_2_FOUND)

mark_as_advanced(SSE2_FOUND SSE3_FOUND SSSE3_FOUND SSE4_1_FOUND SSE4_2_FOUND)

ENDMACRO(FindSSE)

Hi! I found this as first hit on google. I only copied parts of it to test for our supported targets AVX and SSE3. On an AMD machine I then had problems with the SSE3 detection, because as it turns out, SSE3 shows up as pni in /proc/cpuinfo. See this link for reference. Maybe you can fix your comment in line 17 with this information :)