diff options
Diffstat (limited to 'wsutil/CMakeLists.txt')
| -rw-r--r-- | wsutil/CMakeLists.txt | 40 |
1 files changed, 26 insertions, 14 deletions
diff --git a/wsutil/CMakeLists.txt b/wsutil/CMakeLists.txt index fe2d662eac..6741ce4c8c 100644 --- a/wsutil/CMakeLists.txt +++ b/wsutil/CMakeLists.txt @@ -104,24 +104,36 @@ else() endif() if(COMPILER_CAN_HANDLE_SSE4_2) # - # Make sure we have the necessary header for the SSE4.2 intrinsics - # and that we can use it. + # Make sure we have the necessary headers for the SSE4.2 intrinsics + # and that we can use them. # - + # First, check whether we have emmintrin.h and can use it + # *without* the SSE 4.2 flag. # - # Does this add the SSE4.2 flags to the beginning of CFLAGS? + check_include_file("emmintrin.h" EMMINTRIN_H_WORKS) + # - # Note that if there's a mix of "enable SSE 4.2" and"disable - # SSE 4.2" flags, this may not indicate that we can use the - # header. That's not a bug, that's a feature; the other flags - # may have been forced by the build process, e.g. in Gentoo - # Linux, and we want to check this with whatever flags will - # actually be used when building (see bug 10792). + # OK, if that works, see whether we have nmmintrin.h and + # can use it *with* the SSE 4.2 flag. # - cmake_push_check_state() - set(CMAKE_REQUIRED_FLAGS "${SSE4_2_FLAG}") - check_include_file("nmmintrin.h" HAVE_SSE4_2) - cmake_pop_check_state() + if(EMMINTRIN_H_WORKS) + # + # Does this add the SSE4.2 flags to the beginning of + # CFLAGS? + # + # Note that if there's a mix of "enable SSE 4.2" and + # "disable SSE 4.2" flags, this may not indicate that + # we can use the header. That's not a bug, that's a + # feature; the other flags may have been forced by + # the build process, e.g. in Gentoo Linux, and we want + # to check this with whatever flags will actually be + # used when building (see bug 10792). + # + cmake_push_check_state() + set(CMAKE_REQUIRED_FLAGS "${SSE4_2_FLAG}") + check_include_file("nmmintrin.h" HAVE_SSE4_2) + cmake_pop_check_state() + endif() endif() if(HAVE_SSE4_2) set(WSUTIL_FILES ${WSUTIL_FILES} ws_mempbrk_sse42.c) |